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General Discussion => Welcome and General Discussion => Topic started by: sol on June 28, 2014, 09:40:26 PM

Title: solar panel installation
Post by: sol on June 28, 2014, 09:40:26 PM
Since it recently came up in this other thread (http://forum.mrmoneymustache.com/welcome-to-the-forum/what-was-your-largest-single-purchase-of-the-last-12-months/), I thought I'd detail our solar panel installation in Washington State.  NWEdible has a very similar cost breakdown posted over at her blog (http://www.nwedible.com/2014/05/solar-in-seattle.html), and hers is already up and running.

The summary is that we're installing twenty eight 270 watt panels on our south-facing roof, at a cost of $32,400 up front, to replace an estimated 75% of our home energy usage.  (edit 2015: turns out they replace more than 100% of our home energy use.)  This system should more than pay for itself before 2020, after which we will essentially be getting free energy (edit 2019: it paid for itself in August of 2018, after four years of operation).

The Equipment:
In order to get the Washington State production incentives of 54 cents/kWh produced, we have to use all made-in-Washington components.   The 28 panels (http://www.itekenergy.com/products/) are each about 40x65 inches and produce 270 watts, or 275 watts if I wanted to wait an additional month to get the newer panels.  We're using two Eltek THEIA string inverters to convert DC to AC for the house.  Our circuit breaker is already rated for 220 amps and it has plenty of unused slots, so we won't have to pay for any additional house wiring.  Included in our total cost is about $500 for permitting and inspection fees, and the installation of a production meter from our local utility company that will measure how much power we generate, which is used to determine how much to pay us for having solar panels through our net metering agreement.  The total system size should be 7560 kW, and in this part of the world that size of an array should produce about 1:1 on an annual basis.  So we should generate about 7500 kWh of power over the course of the year, most of which will be May through September with only about 3% of the yearly total in December.  At more southerly latitudes, the seasonal variation is less pronounced.

The Installation:
One of the reasons we bought the house was the unobstructed view of the south-facing roof.  Our 28 panels will go in a 4x7 grid, wired together and sent through the roof into our crawlspace/attic, across the house, out one of the birdholes on the side of the house above the garage and straight down to the production meter.  The inverters will be on the interior of the garage on the same wall, behind the power meter.  The panels will take up most of our available roof space, and be mounted flush to the roof on 4 inch standoffs that allow installation over top of shower fan vents and the sewer vent stacks that would otherwise be in the way.  Normally they want you to hose the panels down twice a year, but our roof is higher than all surrounding trees so I expect less maintenance than usual.

The Financial Payback:
The federal tax credit is good until Dec31 2016 and offers a 30% tax credit.  That means we'll get an extra $9720 back on our taxes next April.
If the system produces the expected amount of power, we expect our utility company to cut us a check for about $4200/year every July for the next six years.
Our local production then offsets our local consumption of power, so we buy less power from the power company.  Electricity is only about 8 cents/kWh in this part of the country, so unless you're a real power hog this isn't a major component of the payback, about $50/month.

Add those numbers up and we're expecting about $38520 in payments between now and July 2020 for our $32400 in up front cost.  In my mind, this works out to locking in a return of about 3% per year on $32.4k for the next six years, in exchange for getting most of our power for free after that.  The math is a bit more complicated than that because almost half of that cost comes back to me within a year.

Paying for the system was a complicated mixture of using a 0%-for-9-months credit card with 1% cash back and selling some investments from our taxable account in a way that tried to minimize our capital gains taxes.  We've also turned our W-2 withholding down to $0 for the remainder of the tax year in anticipation of that $9720 tax credit.  I see no point in letting Uncle Sam hold all that money for me.

One Wrinkle
We live in a development with an HOA.  I had to fill out a form notifying the architectural committee of my intentions to install solar panels.  I gave them a schematic drawing of the proposed array and a copy of the state law (http://apps.leg.wa.gov/rcw/default.aspx?cite=64.38.055) that makes it illegal for an HOA to prevent a homeowner from doing something that both the state and the federal government are trying to incentivize.   We'll see if they try to protest.

I'll update thread with details as the system is installed, permitted, turned on, and starts paying me.

Title: Re: solar panel installation
Post by: Zombie Burger on June 28, 2014, 10:03:18 PM
That is pretty awesome! I can't wait to hear how this works out. 
Title: Re: solar panel installation
Post by: Rural on June 29, 2014, 03:03:48 AM
Very cool. I'm excited for you, and my turn is coming...
Title: Re: solar panel installation
Post by: TomTX on June 29, 2014, 06:19:25 AM
I'm actually very surprised at how short the payback period is.  This is awesome.  Six years is nothing. 

What's the expected life of the panels?   And what costs are you expecting for maintenance and upkeep?

State incentives will do that.

One caveat: I believe the federal solar tax credit is NON refundable. It will take your taxes to zero, but won't result in Uncle Sam cutting you a check. If we do this, we plan to look at doing a Traditional-> Roth conversion
Title: Re: solar panel installation
Post by: Phy to FI on June 29, 2014, 07:00:01 AM
This is really cool. Thanks for all the details.
Title: Re: solar panel installation
Post by: teen persuasion on June 29, 2014, 08:05:12 AM
I'm actually very surprised at how short the payback period is.  This is awesome.  Six years is nothing. 

What's the expected life of the panels?   And what costs are you expecting for maintenance and upkeep?

State incentives will do that.

One caveat: I believe the federal solar tax credit is NON refundable. It will take your taxes to zero, but won't result in Uncle Sam cutting you a check. If we do this, we plan to look at doing a Traditional-> Roth conversion

The non refundable credits is the reason we have not done this.  Low income families that owe no income tax to fed or state effectively cannot take advantage of the credits.
Title: Re: solar panel installation
Post by: sol on June 29, 2014, 08:30:38 AM
The tax credit can be carried over to multipe years if you can't use it all this year, so even lower income folks can benefit.  If you're low enough income to never pay any taxes at all then the credit would be wasted.

Expected lifetime is decades. Panels are warrantied for 25 years but there are panels built in the 70s still going strong.  It's not like they have any moving parts, so as long as you don't throw rocks at them they should be fine.  The inverters are also all solid state and apparently they fail under warranty in the first month or not at all.

Maintenance and upkeep should be negligible since we have no nearby trees to shed on them.  I'll hose them off when I clean my gutters annually, sooner if I see the performance dropping.
Title: Re: solar panel installation
Post by: sol on July 25, 2014, 06:28:36 PM
Our solar panels went up today.

Installation took 2 days and went exactly as described above.  28 panels for a total of 7560 watts. 

My power meter is currently running backwards, generating approximately $20/day in free money for the month of August.

Pictures attached are our roof before, during, and after the installation.
Title: Re: solar panel installation
Post by: dragoncar on July 25, 2014, 07:32:32 PM
Sweet... so they rerouted the thingamajiggers (technical term) coming out of the roof?  Like the vent pipes and you lost the skylights?

I haven't even moved into my new house yet, but I'm considering solar.  California doesn't have incentives as sweet as yours, but I think the payback period is still pretty darn good.  But we'd likely have to go w/ net metering and thus would not want to oversize the system.  So my question is this:  Should I wait a whole year to determine our annual electricity usage in order to size the panel?  Or just go by a few months of data?  Any thoughts?

I also plan to have some skylights installed, and would probably want to do both projects at the same/similar time.  Would that make sense?
Title: Re: solar panel installation
Post by: sol on July 25, 2014, 07:40:45 PM
Sweet... so they rerouted the thingamajiggers (technical term) coming out of the roof?  Like the vent pipes and you lost the skylights?

We didn't have any skylights to lose.  The vent pipes are just for burping your plumbing when you flush so you don't get sewer gas backup, and thus they only need to be open to the atmosphere.  They were shortened, and are still there under the panels.  The square things near the roof ridge are attic vents, they didn't move at all.  The panels go right over them.

They put one new hole in our roof to route the power cable into and across our attic, out a bird hole, and down the far side of the house to the inverters and meters.

We are going to put in a solatube over our main staircase, but those things are pretty flexible.  It will just come out on a different roof surface.

Quote
Should I wait a whole year to determine our annual electricity usage in order to size the panel?  Or just go by a few months of data?  Any thoughts?

Our power company provides a whole year of records online.  We sized this system based on our summertime power consumption at our old house, because that house had some electric heating that this house doesn't.  When our first bimonthly power bill at the new house came in at 867kWh for our family of five, I thought maybe we had installed too many panels.  But then I realized our winter consumption is going to be way higher because we don't really use lights in the summer, and the furnace blower isn't on.  And we'll get an electric car in a year or two, so that will use up a bunch of our solar production.  And even if we don't use it on site, the power company still pays us for whatever we produce and it gets used by our immediate neighbors instead.  Net metering solves all problems.

Quote
I also plan to have some skylights installed, and would probably want to do both projects at the same/similar time.  Would that make sense?

Unless the skylights and the solar panels are going to compete for roof space, I don't think it matters.  The condition of your roof matters, though.  If the roof is going to need to be replaced in the next five or ten years, I'd consider doing that first.
Title: Re: solar panel installation
Post by: Roland of Gilead on July 25, 2014, 07:56:39 PM
Very nice.   We have four of those same 270 watt panels that we are going to install on our truck camper.  No tax credit but generating electricity with a gasoline generator is $$$.
Title: Re: solar panel installation
Post by: dragoncar on July 25, 2014, 08:07:05 PM
We sized this system based on our summertime power consumption at our old house, because that house had some electric heating that this house doesn't.
...
Unless the skylights and the solar panels are going to compete for roof space, I don't think it matters.  The condition of your roof matters, though.  If the roof is going to need to be replaced in the next five or ten years, I'd consider doing that first.

Yeah, I'm now wondering how solar power compares to a gas furnace, and whether it would make sense to oversize and use any extra to do some resistive heating during winter (for example, a space heater just in the master bedroom, and lowering the thermostat for the rest of the house).

Unfortunately, the skylights and solar panels both want to be on my south facing slope.  But I have potential shadow sources, so it's not clear cut if that's the best option.  I'll have to observe....

edit: or run a hot tub off electric vs. a more expensive to install gas option, electric car in the future, etc. etc.  For all I know, I have plenty of space for both, it all really comes down to the details.
Title: Re: solar panel installation
Post by: monarda on July 25, 2014, 10:29:17 PM
Congrats, sol!

We have a much smaller system on one of our rentals, 8 panels for 1920 watts, installed in 2012. We'll add 9 more panels someday, but not for a couple of years.  We have Enphase microinverters on our system.  I know there are several different options for inverters,  (string inverters?). I know that microinverters can get expensive for large systems.  I'm curious about the options your installer presented to you.

dragoncar, skylights work really well on north-facing slopes. Don't rule that out...
Title: Re: solar panel installation
Post by: dragoncar on July 25, 2014, 10:41:03 PM
dragoncar, skylights work really well on north-facing slopes. Don't rule that out...

Sorry sol, I never met a thread I wouldn't hijack. 

Thanks for the note, monarda.  Didn't even think about that, although the north slope already has a skylight and that area gets enough light.  But maybe there's a way to build/paint the light wells on the north slope so that it gets reflected back down to the south side, which is pretty dark.  Or, more likely, there's enough room anyways.  I'm sure later on I'll post pictures and solicit contractor recommendations for the bay area.  There's a lot to learn about frugal home ownership.
Title: Re: solar panel installation
Post by: Thegoblinchief on July 26, 2014, 07:33:47 PM
Very cool. Wondering what the payback will look like in 5-10 years when we're on house number two. Too much uncertainty right now about how long we are staying here to put panels on this house.
Title: Re: solar panel installation
Post by: Lizzy B. on October 08, 2014, 01:04:12 PM
I know I'm bringing this thread back from the dead, but thanks very much for all these details. We're in the process of weighing our options and running the numbers on a solar instal and this breakdown was very helpful, even though we're in a different state with different incentives.

Now that you've lived with the system for a few months, what do you think of it? Any surprises?
Title: Re: solar panel installation
Post by: sol on October 12, 2014, 01:25:23 PM
Now that you've lived with the system for a few months, what do you think of it? Any surprises?

Living with solar panels has become very mundane.  They just work.  There is no maintenance, no hassle, no problems.  At least not yet.  It's just like having regular electricity, except that now I can sit on my deck drinking a beer that has been cooled by the sun.

They've been running for 72 days and have generated approximately 2700 kWh of power, a bit more than I was expecting based on my initial calculations.  Multiplied by the $0.54/kWh production incentive rate, I've already earned almost $1500.  About $20/day average even as the days have been getting shorter.

Our first power bill came in a while back.  We get billed every two months, and we had our panels up and running for about six weeks of the billing period for a net surplus of 1402 kWh produced in excess of what we used.  Our semi-monthly power bill went from $83 to -$103 dollars after the $11 "customer connection charge" is included.

The $103 credit on our bill was applied against our water bill, lowering our total bill even further.  Not quite to zero, though. 

The real question will be what happens with the costs next year.   Our early tax forms suggest we should qualify for $9720 in tax rebate next April and I'm expecting about $4200 in incentive payment from the utility next July/August.  I'll report back when we get there.


Title: Re: solar panel installation
Post by: TomTX on October 12, 2014, 03:07:23 PM
Washington has some really impressive incentives.
Title: Re: solar panel installation
Post by: hwstar on October 12, 2014, 06:33:57 PM
I've got a small 1kW battery backup/UPS system not connected to the grid I designed and installed myself just to see what was involved in self-installation. It powers my computers and electronics in the house on a dedicated circuit.

The biggest risk was is getting the brackets for the panels installed into the rafters. It requires precise measuring skills.

I think that having a system installed by a professional almost triples the total system cost. There are lots of contractors on my area running full page ads in the newspapers. To cover the cost of running those ads, you know they are charging way more than necessary.

Looking on the web, I see 3kW grid tie Enphase kits selling for $6.5k. If you are electrically and mechanically inclined, I would check out what is being offered,
but make sure you don't have issues with insurance or permits before purchasing a system.

Title: Re: solar panel installation
Post by: sol on February 18, 2015, 08:51:41 PM
An update on our solar panels as winter draws to a close...

My 7560W of rooftop solar panels have produced about 4300 kWh of electricity since going live July 30.  That's 6.5 months through the dark northwest winter. 

The insolation maps predict that the 7 months of August through February should produce 43% of our annual energy.  Doing the math on what my system has produced, I expect our 7500W are going to produce close to 10,000 kWh in the first year, which at 54 cents/kWh produced means we're going to exceed the $5000/year maximum state production incentive payment. 

I'm not really complaining about leaving money on the table.  In fact I'm thrilled they're producing so much more than expected.  Maybe because it's been such an unusually sunny and dry winter?

If my math holds up, this higher-than-expected production value means that by the time our incentive payments stop in 2020 we will have collected $30k in payments plus $8800 in reduced power costs for an effective rate of return of 3.7 percent (on my $32.4k outlay) over six years instead of the 2.95% I was previously expecting.  I'm thinking of this like buying a 3.7% tax free bond with a six year duration, and in exchange I get free power for the remaining life of my system.  Which I'm hoping is 20+years.

A second side effect of this new higher production is that combined with some efficiency improvements, I'm pretty sure my house is going to end up with a net negative electricity consumption for the year.  Do I get a sticker?
Title: Re: solar panel installation
Post by: gimp on February 18, 2015, 11:39:31 PM
Yeah you get a fucking sticker. Awesome.

The EE in me wonders about future wiring for houses - quite a lot of our devices operate on DC power, solar panels generate DC power, but it gets converted to AC and back since all our sockets, wiring, fuses, etc etc, operates on AC. I wonder if in the future we'll have an amount of pure DC sockets, with simple compatibility for simple devices (like heating elements). For example, if a house has an electric heating system, building it to operate on AC or DC would be a major efficiency boost since it's one of the biggest electric costs. Ditto boiler / water heater, oven, fridge - the big expensive energy-slurping devices. Bit more up-front expense on designing the proper home electrical system, and the proper dual-type electrical devices, but hopefully over the long term it would be worth it with efficiency gains.

I also think we will shortly need to rethink the way we bill power - there should be two line items: fixed costs for grid maintenance, expansion, and operation; and variable costs for energy usage. Some places already do this, but some will need to. No matter how much power we generate with solar panels, we still have to pay for the grid! (Especially since time-variable power sources like wind and solar require a somewhat different approach to storage and on-demand generation.)

Anyways, cool stuff. The more we can generate off rooftop power, the less we have to rely on single sources of power. The more we buy, the cheaper it gets. I'm looking forward to control microprocessors embedded into each solar cell on each solar panel.
Title: Re: solar panel installation
Post by: Dexterous on February 19, 2015, 12:40:31 AM
Thanks for all the detailed information Sol.  I plan to install solar in the distant future, so it was interesting to read your experience. 

What's awesome is that solar technology has a lot of room for improvement, so we'll be able to generate even more power in smaller spaces each few years.
Title: Re: solar panel installation
Post by: Roland of Gilead on February 19, 2015, 06:25:12 AM
$0.54 per Kwh?   We pay about $0.10 per Kwh for our electricity in the NW.


At $0.54 per Kwh I could make money by running a gasoline generator using $2 a gallon gas (get about 10kwh out of a gallon)

A 10kw generator running for an hour would cost $2 and generate a profit of $3.40.

1000 hours = $3400.


Hmmm...
Title: Re: solar panel installation
Post by: brooklynguy on February 19, 2015, 06:45:50 AM
I'm thinking of this like buying a 3.7% tax free bond with a six year duration, and in exchange I get free power for the remaining life of my system.

What about the market value of the solar panel system itself?  Does it materially enhance the value of your home (or perhaps detract from it)?

What's awesome is that solar technology has a lot of room for improvement, so we'll be able to generate even more power in smaller spaces each few years.

How quickly is solar panel technology expected to advance?  If this technology is going to follow the path of the personal computer and allow a pocket-sized panel to power a city in the near future, I wouldn't want to be an early adopter stuck with today's lumbering panels on my roof.  It was an easier decision for sol because WA's generous incentives speed up the breakeven point, but the last time I looked into the possibility of solar power the math didn't work out in my favor.  And my initial layman's assessment was that my small roof doesn't have sufficient space for the panels between the skylights and other obstructions.  Also, the possibility of installing solar panels competes in my mind with the possibility of installing a living green roof, unless it is possible for those two systems to coexist on my roof.
Title: Re: solar panel installation
Post by: Thegoblinchief on February 19, 2015, 06:46:52 AM
$0.54 per Kwh?   We pay about $0.10 per Kwh for our electricity in the NW.


At $0.54 per Kwh I could make money by running a gasoline generator using $2 a gallon gas (get about 10kwh out of a gallon)

A 10kw generator running for an hour would cost $2 and generate a profit of $3.40.

1000 hours = $3400.


Hmmm...

The $0.54 rate is the inflated reimbursement rate because it's renewable electricity.
Title: Re: solar panel installation
Post by: dragoncar on February 19, 2015, 11:29:46 AM
I'm thinking of this like buying a 3.7% tax free bond with a six year duration, and in exchange I get free power for the remaining life of my system.

What about the market value of the solar panel system itself?  Does it materially enhance the value of your home (or perhaps detract from it)?

What's awesome is that solar technology has a lot of room for improvement, so we'll be able to generate even more power in smaller spaces each few years.

How quickly is solar panel technology expected to advance?  If this technology is going to follow the path of the personal computer and allow a pocket-sized panel to power a city in the near future, I wouldn't want to be an early adopter stuck with today's lumbering panels on my roof.  It was an easier decision for sol because WA's generous incentives speed up the breakeven point, but the last time I looked into the possibility of solar power the math didn't work out in my favor.  And my initial layman's assessment was that my small roof doesn't have sufficient space for the panels between the skylights and other obstructions.  Also, the possibility of installing solar panels competes in my mind with the possibility of installing a living green roof, unless it is possible for those two systems to coexist on my roof.

I'm with you - although solar appeals to me, I expect to reap the benefits through reduced grid prices once solar becomes cheap enough.  The only thing making it attractive now is external incentives (which aren't so hot anymore in my area).  I'll still run the numbers once a year.
Title: Re: solar panel installation
Post by: gimp on February 19, 2015, 01:44:25 PM
Quote
How quickly is solar panel technology expected to advance?  If this technology is going to follow the path of the personal computer and allow a pocket-sized panel to power a city in the near future, I wouldn't want to be an early adopter stuck with today's lumbering panels on my roof.

Computers have advanced because they benefit from moore's law - and let me belabor the point a little because so many people get this wrong.

Moore's law is an observation, that guides R&D spending for the big dogs; the observation is this: every ~2 years, give or take, the number of transistors you can place cheaply in a certain area doubles. That is, if today's chip has 1 billion transistors in 100 square millimeters, two years from now the same price buys you either 2 billion transistors, or half the silicon area (price) buys you the same 1 billion. This is only a law while it lasts, but it has lasted about 40-45 years, and will probably last a while yet - all doom and gloom predictions have thus far failed to materialize (though undoubtedly there are limits to the way we do things now, we change the way we do things as time goes on; traditional planar scaling ended at 90nm about 5 generations / ~10 years ago, but you haven't noticed.)

What does not really go down is the price of silicon itself. In fact, the price of silicon wafers only really goes down when wafers transition sizes - 8 inch to 12, or the upcoming 12 to 18. Interesting side note: each transition has knocked out about half the competition, because dealing with bigger wafers means massive expenses.

So you see, moore's law benefiting computers is economics more so than physics.

Solar panels, however, don't benefit from smaller transistors. Solar panels are silicon but the cost of silicon is... well, the cost of obtaining, purifying, growing, cutting, processing, and shipping sand, more or less.

Efficiency gains in solar panel energy production don't follow moore's law - entirely different beast. (If they did, we'd have nearly infinite energy in a couple decades, just as we now have seemingly infinite compute power compared to two decades ago.)

Advancement in solar panels is as follows, roughly speaking:

- Efficiency, small improvements, using different materials and geometries. There're black solar panels, which are far more efficient than your usual panels, but also prohibitively expensive for all but the most critical applications (space).
- Cost reduction; high volume manufacturing means cost all along the supply chain can reduce; time and money make this happen.
- Weight reduction: cutting panels thinner makes them weigh less; less material means less cost, and you also get less cost since they're easier to transport and install.
- Power conversion efficiency in surrounding systems - that is, better and cheaper inverters that last longer.
- Sun-following and weather-predicting gets more power and helps grids balance better.
- Form factors for different needs. For example, foldable flexible solar panel sheets that can be rolled up and carried in a backpack. Downside: far less power generated.
- We'll most likely start putting controllers right into the solar panel silicon - microchips embedded into each cell to improve efficiency by rerouting power around poorly-performing cells (also see solar tracking and weather prediction.)

The short of it all is this: if you put a solar panel up on the roof today, the panels in 20 years will be cheaper, lighter, smarter, but not nearly efficient enough to make your old panels useless.
Title: Re: solar panel installation
Post by: dragoncar on February 19, 2015, 03:30:58 PM
Quote
How quickly is solar panel technology expected to advance?  If this technology is going to follow the path of the personal computer and allow a pocket-sized panel to power a city in the near future, I wouldn't want to be an early adopter stuck with today's lumbering panels on my roof.

Computers have advanced because they benefit from moore's law - and let me belabor the point a little because so many people get this wrong.

Moore's law is an observation, that guides R&D spending for the big dogs; the observation is this: every ~2 years, give or take, the number of transistors you can place cheaply in a certain area doubles. That is, if today's chip has 1 billion transistors in 100 square millimeters, two years from now the same price buys you either 2 billion transistors, or half the silicon area (price) buys you the same 1 billion. This is only a law while it lasts, but it has lasted about 40-45 years, and will probably last a while yet - all doom and gloom predictions have thus far failed to materialize (though undoubtedly there are limits to the way we do things now, we change the way we do things as time goes on; traditional planar scaling ended at 90nm about 5 generations / ~10 years ago, but you haven't noticed.)

What does not really go down is the price of silicon itself. In fact, the price of silicon wafers only really goes down when wafers transition sizes - 8 inch to 12, or the upcoming 12 to 18. Interesting side note: each transition has knocked out about half the competition, because dealing with bigger wafers means massive expenses.

So you see, moore's law benefiting computers is economics more so than physics.

Solar panels, however, don't benefit from smaller transistors. Solar panels are silicon but the cost of silicon is... well, the cost of obtaining, purifying, growing, cutting, processing, and shipping sand, more or less.

Efficiency gains in solar panel energy production don't follow moore's law - entirely different beast. (If they did, we'd have nearly infinite energy in a couple decades, just as we now have seemingly infinite compute power compared to two decades ago.)

Advancement in solar panels is as follows, roughly speaking:

- Efficiency, small improvements, using different materials and geometries. There're black solar panels, which are far more efficient than your usual panels, but also prohibitively expensive for all but the most critical applications (space).
- Cost reduction; high volume manufacturing means cost all along the supply chain can reduce; time and money make this happen.
- Weight reduction: cutting panels thinner makes them weigh less; less material means less cost, and you also get less cost since they're easier to transport and install.
- Power conversion efficiency in surrounding systems - that is, better and cheaper inverters that last longer.
- Sun-following and weather-predicting gets more power and helps grids balance better.
- Form factors for different needs. For example, foldable flexible solar panel sheets that can be rolled up and carried in a backpack. Downside: far less power generated.
- We'll most likely start putting controllers right into the solar panel silicon - microchips embedded into each cell to improve efficiency by rerouting power around poorly-performing cells (also see solar tracking and weather prediction.)

The short of it all is this: if you put a solar panel up on the roof today, the panels in 20 years will be cheaper, lighter, smarter, but not nearly efficient enough to make your old panels useless.

Moore's law is actually about the number of transistors per package at which manufacturing cost is minimum.  This can (and has) meant larger total chip area, so it's not necessarily density per se.

Everyone interested should read the original paper, which is only about 3 pages of actual text.
http://www.monolithic3d.com/uploads/6/0/5/5/6055488/gordon_moore_1965_article.pdf
Title: Re: solar panel installation
Post by: Sunny on February 19, 2015, 03:55:33 PM
It was wonderful to read about your installation and success.  My installation in Illinois was completed in late August 2014.  Despite issues with ComEd installing the proper meter five months late, our production has been great.   Today's I checked at 4 pm and we had produced 45.50 KWH.   Solar around here is rare and I'm planning to start a blog as I educate myself about what a residential solar homeowner needs to know.

I am currently getting used to real-time pricing, which solar owners are encouraged to use.

Illinois offers a 25% renewable energy rebate and the 2014 awards are being held up by our new Governor Rauner. 

Just heads up too, regarding the 30% federal tax credit presently ends with the 2016 tax year.  It is impossible to say at this point If it will be renewed. 
Title: Re: solar panel installation
Post by: Mrs. PoP on February 19, 2015, 05:53:22 PM
Missed this when it was first posted, but the timing is great as our system is scheduled to begin installation next week. 

Ours will be very similar in size to Sol's, 28 panels arranged 2x14 on our south facing back roof deck with excellent exposure to the sun in S FL.  The system will be rated for ~7.56kW, but should produce over 10,000 kWh of power throughout the year, enough to power 100% of our power needs. 

Our upfront costs are ~$30K, $9K of which will be coming back to us on our 2015 federal taxes, and ~$15K of which will be coming  back to us a couple of months after we finish the installation in the form of FPL (our utility company) rebates to the tune of $2/watt that we successfully applied for in January. 

Our net out of pocket will be $6K, which equates to just about 5 years worth of energy cost based on the past couple of years worth of usage (~$100/mo average). 

I'm really excited to have them go up!  Fingers crossed the installation goes smoothly. 
Title: Re: solar panel installation
Post by: gimp on February 19, 2015, 09:36:05 PM
Quote
Moore's law is actually about the number of transistors per package at which manufacturing cost is minimum.  This can (and has) meant larger total chip area, so it's not necessarily density per se.

Splitting hairs. I have both his paper and speech hosted on my website as well. Considering that the cost of wafers hasn't changed much over the past couple generations for given requirements, having the same cost per piece of silicon almost necessitates having a very similar area. All the other factors - margin for profit, margin to pay for R&D, margin to pay for tooling and fabs - are also a different topic.

Quote
The complexity for minimum component costs has increased at a rate of roughly a factor of two per year (see graph on next page). Certainly over the short term this rate can be expected to continue, if not to increase.

Quote
The new slope might approximate a doubling every two years, rather than every year, by the end of the decade.

We can also chat about packaging costs, which people seem to forget - but between generations, they also don't change much (at least not for single chips, certainly in aggregate a 30 cent difference matters.)

Anyways. We can agree solar panels don't do these things.
Title: Re: solar panel installation
Post by: sol on February 20, 2015, 06:57:58 PM
At $0.54 per Kwh I could make money by running a gasoline generator using $2 a gallon gas (get about 10kwh out of a gallon)

Yea, that crazy 54 cent number is because Washington is trying to encourage people to install panels and inverters made in Washington by Washington companies.  If you use out-of-state equipment the incentive payments are less attractive.

So naturally the locally made equipment costs more.  It's basically a subsidy to the local companies by the state legislature, by way of intermediate consumers like me.  But those companies are smart enough to figure out what to charge so that consumers will opt to pay more for local equipment and get the higher incentive payments.

What about the market value of the solar panel system itself?  Does it materially enhance the value of your home (or perhaps detract from it)?

As a ballpark, I think the panels are worth roughly half of their retail installation cost after one year, but it doesn't matter much to me because we're not planning on selling until the panels are fully depreciated.

What's awesome is that solar technology has a lot of room for improvement, so we'll be able to generate even more power in smaller spaces each few years.

Solar panels are ultimately limited by the energy available in sunlight at your location.  They might get two or three times better over the coming century, but they won't ever get 10 times better. 

I think the biggest risk, for a homeowner looking at a solar installation, isn't that the panels will be made more efficient but that they'll be made obsolete by some other power technology that essentially solves the energy crisis.  We'll all feel pretty silly about paying $30k for residential solar panels if power costs drop to to 1 cent per kWh plus grid maintenance costs.  I don't think anyone expects that to happen in the next 20 years, but over the century timescale I think it's possible.
Title: Re: solar panel installation
Post by: sol on February 20, 2015, 07:13:46 PM
Thinking about this today has made me think I've done my math wrong because I neglected the 30% federal tax credit in the above analysis in post 19 (http://forum.mrmoneymustache.com/welcome-to-the-forum/solar-panel-installation/msg561301/#msg561301).

My up front cost was 32,400.  That money is gone, so I'm $32,400 in the hole on day one.  Over the next six years I'll collect $30,000 in incentive payments, $9720 in tax rebate, and about $800/year in reduced power bills for a six year total of $44,520.

My $32,400 initial investment would have to grow at 6.56% per year to be worth $44,520 after six years, assuming annual compounding.

And my return should actually be a little better than that, because I'm getting about a third of that total ($9720+$5000+$800) back in the first year, not at the end.  So I can reinvest it elsewhere for the remaining five years of the six year cycle.  Also power costs might go up over that six years, slightly increasing my return a bit more.

Someone check my math on this?  I feel like I'm missing something important here.  My original estimate was to expect about 3.2% return (in original post (http://forum.mrmoneymustache.com/welcome-to-the-forum/solar-panel-installation/msg329655/#msg329655) up top) based on 7560 kWh of production per year, and my new estimate is about 6.5% return based on 10,000 kWh of production. 

It amazes me that a 30% higher than expected production number has almost doubled my ROI on these solar panels, but between the 54 cents/kWh incentive and the 8.5 cents/kWh reduction in power purchased, it adds up in a hurry.  Of course, that 30% apparent increase in production is just based off of six dark months so far, so we'll have to see how it actually pans out after a full year.
Title: Re: solar panel installation
Post by: ChrisLansing on February 20, 2015, 07:45:38 PM
Yeah you get a fucking sticker. Awesome.

The EE in me wonders about future wiring for houses - quite a lot of our devices operate on DC power, solar panels generate DC power, but it gets converted to AC and back since all our sockets, wiring, fuses, etc etc, operates on AC. I wonder if in the future we'll have an amount of pure DC sockets, with simple compatibility for simple devices (like heating elements). For example, if a house has an electric heating system, building it to operate on AC or DC would be a major efficiency boost since it's one of the biggest electric costs. Ditto boiler / water heater, oven, fridge - the big expensive energy-slurping devices. Bit more up-front expense on designing the proper home electrical system, and the proper dual-type electrical devices, but hopefully over the long term it would be worth it with efficiency gains.

I also think we will shortly need to rethink the way we bill power - there should be two line items: fixed costs for grid maintenance, expansion, and operation; and variable costs for energy usage. Some places already do this, but some will need to. No matter how much power we generate with solar panels, we still have to pay for the grid! (Especially since time-variable power sources like wind and solar require a somewhat different approach to storage and on-demand generation.)

Anyways, cool stuff. The more we can generate off rooftop power, the less we have to rely on single sources of power. The more we buy, the cheaper it gets. I'm looking forward to control microprocessors embedded into each solar cell on each solar panel.

Before rural electrification a lot of farms had wind turbines that produced DC power.   The outlets/lights were DC.    32 volts, if memory serves.   

Maybe you would know this - can LED lights work on DC?   
Title: Re: solar panel installation
Post by: gimp on February 20, 2015, 08:08:22 PM
I did not know that about rural areas using DC. Turbines / generators can be built to produce either DC or AC, without much issue (different geometries, not bulky / expensive / lossy converters.) Just how you can have DC and AC motors. 32 volts, very interesting. Good information!

LEDs work on DC. LED lights in place of lightbulbs take your AC from the socket and rectify it back into DC. Actual light bulbs don't give a shit whether it's AC or DC, they just heat a filament till it produces light regardless of how the electrons are wiggling or moving.

LEDs work on DC because LEDs - light emitting diodes - are diodes, meaning they pass current one way. (Okay, ignore breakdown voltages and zener diodes.) They are very simple devices to use.

Cool LED facts:

They're a bit of an art to make - certainly science, but a bit of an art as well, due to things like color variation.

White LEDs are actually blue. It's actually more complicated than that but that's a decent summary. A more expensive way to do it is to mix two colors (eg, blue and yellow) or three (red-green-blue). Fancy LED bulbs can have controllable color - simply grab a remote and make it more yellow, or more red, or more white, or whatever you want.

Superbright LEDs are complicated to design because they take so much power. A light bulb might be a 60W device, but it's very simple - metal contacts, glass shell, filament, no air inside. Everything is designed to deal with the heat properly, and it's a known design, and trivial now. A superbright LED that takes 3W, on the other hand, sits on a circuit board which unlike a piece of metal does not like heat nearly as much. So a 12W LED bulb might have several LEDs, which much be arranged in a careful pattern, with proper heat sinks. Not only that, but they have to be mindful that heat builds up and has nowhere to go; they don't stick fans on these things, and especially if the bulb is on the ceiling upside-down... the heat builds up. So the bulbs have the be designed very carefully to not fail due to heat in reasonable operating conditions. This was, and still is, a large reason for the high cost of LED bulbs. I can buy superbrights for a few cents each, and the rectifier and other circuitry might be a dollar in low volume... but the enclosure, and spacing, and layout, all took quite a bit of R&D to get right, and that has to be paid for. For this reason, LED bulbs get cheaper every year; I would not be surprised to see them in the $2 range within a few years at hardware stores.
Title: Re: solar panel installation
Post by: ChrisLansing on February 21, 2015, 06:21:36 AM
@ gimp   Thank you, interesting info.   

@ OP  A very inspiring thread.    I'm going to look into the incentives here in MI.     

Question, how do you repair the shingles under the panels?   Do they just get removed when the time comes to re-shingle?   Is it manageable for one or two people to remove the panels?   

A second question,  my house has a gable at the S side, could I mount panels on the S wall instead of on the roof?      I know they can be mounted that way, but I'm wondering about having the correct angle.   
Title: Re: solar panel installation
Post by: brooklynguy on February 21, 2015, 06:23:11 AM

My $32,400 initial investment would have to grow at 6.56% per year to be worth $44,520 after six years, assuming annual compounding.

...

Someone check my math on this?  I feel like I'm missing something important here.  My original estimate was to expect about 3.2% return (in original post (http://forum.mrmoneymustache.com/welcome-to-the-forum/solar-panel-installation/msg329655/#msg329655) up top) based on 7560 kWh of production per year, and my new estimate is about 6.5% return based on 10,000 kWh of production. 

If you're trying to figure out your rate of return with annual compounding, your arithmetic is off.  Your expected return using your original numbers should have been 2.93%.  Your expected return using your updated numbers is 5.44%.  However, none of this changes either of your overall points, that (i) this is a great return on investment (especially considering that, as you said, the return is actually higher because some of your return of capital is front-loaded, your energy savings may be higher than projected (but of course this could cut the other way too, if power rates go down), and you are ignoring for purposes of this calculation the almost-free energy you will be getting for the remaining life of the system after the six year period) and (ii) the higher-than-expected energy production almost doubled your return on investment. 

That said, the ROI figures you quotes are closer to the actual ROI without compounding (which are actually 3.1%, using the original numbers, and 6.2%, using the updated numbers).  For your analysis, I think it makes more sense to ignore compounding (treating your investment like a bond that pays interest annually, rather than a zero-coupon bond that compounds interest).  As stated above, by using annually compounded rate of return as your metric and ignoring the effect of the early return of capital, you are materially understating your return.  Because so much of your return of capital is front-loaded, you are correct that your true return is even higher than the nominal 6.2% figure (even if you continue to ignore the other factors identified above that make your actual return higher still).

An even better analysis would treat your investment as a bond that makes payments exactly when you will actually be receiving your payments so we don't have to ignore the effect of front-loaded payments, but I'm way too lazy to attempt to calculate ROI that way.
Title: Re: solar panel installation
Post by: NaturallyHappier on February 21, 2015, 06:54:55 PM
Great investment.   Here is a summary of my solar journey.


Initial Install                       $90,136.00
PA Grant                              -$22,500.00
Federal rebate                      -$27,014.00
Expansion                               $33,610.00
Federal rebate                      -$10,083.00
Total Out of Pocket               $64,149.00
   
Srec Sales 2010   -$2,580.00
Srec Sales 2011   -$4,070.00
Srec Sales 2012   -$4,810.00
Srec Sales 2013   -$10,070.00
Srec Sales 2014   -$10,832.50
Srec Sales 2015   $0.00
Total Srec          -$32,362.50
   
Power Saved/Income 2010   -$1,757.45
Power Saved/Income 2011   -$2,300.66
Power Saved/Income 2012   -$2,455.59
Power Saved/Income 2013   -$3,265.91
Power Saved/Income 2014   -$3,406.98
Power Saved/Income 2015   $209.73
Total Power Saved.Income   -$12,976.87
   
Remaining Payoff    $18,809.63
   
Projected Yearly Income   $14,200.00
Years left for payback            1.32462202112676
Payoff Date                           5/21/2016
Title: Re: solar panel installation
Post by: monarda on February 22, 2015, 10:25:47 AM
Nice numbers, FranklinBuffett!

What's the size of your system?  It seems to be that the larger the system, the quicker the payback.
Title: Re: solar panel installation
Post by: NaturallyHappier on February 22, 2015, 10:53:00 AM
It was 11.5 KW when I initially installed it in April of 2010.  I expanded it in April of 2013 to 17.5 KW. 

I got somewhat lucky.  When I installed the system in 2010 Solar Renewable Energy Credits (SRECs) in PA were bring $325.00 per MW generated.  The market crashed and then went down to $5.00.  In 2010 PA residents could sell SRECs in Washington DC and Ohio as well as PA.  When the PA market crashed DC revised their laws to exclude out of state SRECs except if the system was registered prior to JAN 2011.  Now I sell my SRECs to DC for $480.00 each.  PA SRECs are currently only selling for $50.00 each.

I capitalized on my good luck and expanded the system in 2013, or it would be paid off already.
Title: Re: solar panel installation
Post by: MrFrugalChicago on February 22, 2015, 01:25:15 PM
I heard the solar panels lose a little bit of efficiency each year, and after 10 or so years are only making half the power.  Is this no longer true? Or do they lose power faster?
Title: Re: solar panel installation
Post by: sol on February 22, 2015, 01:35:54 PM
I heard the solar panels lose a little bit of efficiency each year, and after 10 or so years are only making half the power.  Is this no longer true? Or do they lose power faster?

Not quite that fast.  Most of the estimates for new panels are less than 1% per year, with the fastest degradation happening in places where it is sunny and hot, like Arizona.  Solar panels are more efficient and last longer in cooler temperatures.

Here in Washington we tend to get a lot of sunny but cooler days, so the panels shouldn't degrade quite so quickly.  We also benefit from regular rain to wash of the dust and grime that degrades panels in other parts of the country.
Title: Re: solar panel installation
Post by: NaturallyHappier on February 22, 2015, 02:38:06 PM
I heard the solar panels lose a little bit of efficiency each year, and after 10 or so years are only making half the power.  Is this no longer true? Or do they lose power faster?

Not quite that fast.  Most of the estimates for new panels are less than 1% per year, with the fastest degradation happening in places where it is sunny and hot, like Arizona.  Solar panels are more efficient and last longer in cooler temperatures.

Here in Washington we tend to get a lot of sunny but cooler days, so the panels shouldn't degrade quite so quickly.  We also benefit from regular rain to wash of the dust and grime that degrades panels in other parts of the country.

I have not observed any degradation of output after 5 years, but I have to admit that it would be very hard to tell because of the variability of the weather.

If I had to guess, I would say they will eventually fail like a window would fail in your home.  The seal will break between the glass and the frame and moisture will get into the panel.

I have had to replace 4 panels and an inverter because I had a lightning strike, but this was covered by my homeowners insurance.  I also replaced one panel because it blew off the racking.  This was caused by it not being installed correctly.
Title: Re: solar panel installation
Post by: gimp on February 24, 2015, 02:13:35 PM
I heard the solar panels lose a little bit of efficiency each year, and after 10 or so years are only making half the power.  Is this no longer true? Or do they lose power faster?

The entire system loses efficiency over time. Solar panels get less efficient, and also inverters, batteries, and anything else you have, gets less efficient with age as well. This is different from outright failure going from full to zero after a hailstorm or something.

The current figures are something like: 25 years should still see at least 80% of the original efficiency. Some do better. http://energyinformative.org/lifespan-solar-panels/

If you get one of those deals, like from solarcity, where someone else pays for the solar panels and takes your federal/state refund and sells you the resultant energy at a lower cost than the grid, they don't do so in perpetuity - after, for example, 20 years (depending on the contract) your business relationship is finished and you keep the panels. That means you'd estimate about 10 years of free (less maintenance if applicable) generation after 20 years of paid-for power. Generally speaking, modern panels are considered to last 30 years. I assume that they will usually last longer than that.
Title: Re: solar panel installation
Post by: HelloImNotHome on March 01, 2015, 11:28:24 PM
If anyone has questions about how SolarCity financing options work let me know. I can also send a blank copy of the contract if you wanna see the fine print. If you have questions about system size and options I know a few of the little things they don't specifically advertise to customers that can get you a lower effective rate for power depending on the plan and a few details about the home.

I work there as a PV Designer / Energy Consultant.

Also, dunno if people know this but just like Ting (the referral thread being how I found this site) SolarCity has a sweet option that gives you $250 ( you have to agree to be sent a 1099 at the end of the year) for every referral you submit to a Consultant that gets installed.

Happy to help with any questions.
Title: Re: solar panel installation
Post by: HelloImNotHome on March 01, 2015, 11:35:01 PM
Hello Gimp,

Just so you know with SolarCity if you select a plan that allows SolarCity to collect the Tax Credit then you are in effect leasing the system. If you select the lease option you are never give the option to buy the system, after 20 years you can renew for an additional 10 (keeping your same fixed rate). On a power purchase agreement (PPA) at any point past the 5 year mark or when you sell your home you may purchase the system at fair market value as determined by an independent 3rd party. In my opnion the PPA is the best option for people that are not in a tax liability position but want to own the system eventually.

Hope this helps

- Robert
SolarCity PV Designer / Energy Consultant.


I heard the solar panels lose a little bit of efficiency each year, and after 10 or so years are only making half the power.  Is this no longer true? Or do they lose power faster?

The entire system loses efficiency over time. Solar panels get less efficient, and also inverters, batteries, and anything else you have, gets less efficient with age as well. This is different from outright failure going from full to zero after a hailstorm or something.

The current figures are something like: 25 years should still see at least 80% of the original efficiency. Some do better. http://energyinformative.org/lifespan-solar-panels/

If you get one of those deals, like from solarcity, where someone else pays for the solar panels and takes your federal/state refund and sells you the resultant energy at a lower cost than the grid, they don't do so in perpetuity - after, for example, 20 years (depending on the contract) your business relationship is finished and you keep the panels. That means you'd estimate about 10 years of free (less maintenance if applicable) generation after 20 years of paid-for power. Generally speaking, modern panels are considered to last 30 years. I assume that they will usually last longer than that.
Title: Re: solar panel installation
Post by: b4u2 on March 27, 2015, 08:47:39 AM
Being an electronic technician I have always wanted solar power for my house. I have just never figured out how to pay for it. I am still in debt payoff leg of reaching FI. I did build one panel myself from scratch a few years ago. It works but never had enough money to build or buy more. I see these $30k systems being installed and love the idea but just don't know how to pay for it. Iowa does not have, at least to my knowledge, a very good incentive plan for solar. The front of my house faces south with roof and would be ideal, I think, for a solar panel system. I plan on being in this house 10-15 more years but not sure if it would still be worth it for me.
Title: Re: solar panel installation
Post by: gimp on March 27, 2015, 12:32:26 PM
Good to know, solarcity guy.

b4u2, perhaps you should talk to the solarcity guy who posted right above yours.
Title: Re: solar panel installation
Post by: Axecleaver on March 27, 2015, 12:47:22 PM
Related to the discussion on Moore's law and how the price of solar panels is changing... Good article and graph here about solar panel installation prices:

http://www.pv-magazine.com/news/details/beitrag/us-installed-solar-pv-costs-continue-to-fall_100016490/#axzz3Th5jnVCr

Median installed price in 2013 was $4.70/watt. Compare to $12/watt in 1998. Prices today in my area are around $3.50/watt (under 10k watts). The ROI breakeven for us in upstate NY is about 4-5 years, due to weather (bad), being quite a ways north (bad), but high cost of electricity (gov't here is very tax-heavy).
Title: Re: solar panel installation
Post by: brooklynguy on April 07, 2015, 08:19:13 AM
Came across this yesterday and thought it sounded interesting:

http://www.gocloudsolar.com/

It's a start-up that basically allows you to purchase one or more solar panels (or a fractional interest in a single solar panel), then let the company install and maintain your panel(s) in their solar farm and, on your behalf, sell the electricity generated by your panel(s).

A single full panel costs $750, and CloudSolar estimates that the total economic output over a 25-year period is $2,250 (of which CloudSolar will take a 20% cut for their services).  But the website's disclosure is woefully inadequate regarding the details of this estimate.

The website makes a half-hearted attempt to couch this whole enterprise in non-investment terms ("we're selling solar panels and related services, not an investment vehicle")--no doubt primarily to avoid securities law issues--but it's interesting to compare the expected return to what an individual homeowner can expect to achieve.  The stated expected return (which, according to the website's FAQ, seems to include anticipated government tax credits and incentives) falls short of sol's anticipated return (as outlined earlier in this thread), even before reduction for the company's 20% fee.  But it might compare more favorably with the economic performance of a solar system for an individual residing outside Washington State with less generous incentive programs.
Title: Re: solar panel installation
Post by: Roland of Gilead on April 07, 2015, 08:27:29 AM
Horrible deal.   You can buy a government E-bond that is guaranteed to double in value ($750 to $1500) in 20 years.  No fee and essentially zero risk (if you believe the USA will still be around in 20 years)
Title: Re: solar panel installation
Post by: nereo on April 07, 2015, 08:40:40 AM
Quote
Came across this yesterday and thought it sounded interesting:

http://www.gocloudsolar.com/

It's a start-up that basically allows you to purchase one or more solar panels (or a fractional interest in a single solar panel), then let the company install and maintain your panel(s) in their solar farm and, on your behalf, sell the electricity generated by your panel(s).
Horrible deal.   You can buy a government E-bond that is guaranteed to double in value ($750 to $1500) in 20 years.  No fee and essentially zero risk (if you believe the USA will still be around in 20 years)

It may not be a great investment idea, but I dont' think that's the market they are going after.  Seems this company is trying to appeal to people who want to use solar power but can't install them where they live.  Depending on whether you view it cynically or optimistically their customers are engaging in a simple 'feel-good' exercise in green living or they are legitimately offsetting their energy use with increased solar-capacity to the grid.

Is it a smart investment strategy?  I doubt it.  Is it doing the planet a net-good?  maybe.  Does it make certain people feel better about themselves?  Probably.
Title: Re: solar panel installation
Post by: Roland of Gilead on April 07, 2015, 08:45:09 AM
True.  I sometimes forget that people are idiots and it is very easy to take advantage of them.
Title: Re: solar panel installation
Post by: Patrick A on April 07, 2015, 09:03:13 AM
Awesome thread - I am also in PNW and considering doing this when I get a house.  Thanks for all of the interesting information.
Title: Re: solar panel installation
Post by: nereo on April 07, 2015, 09:03:33 AM
True.  I sometimes forget that people are idiots and it is very easy to take advantage of them.
wow.  I mean, just... wow.   Of all the things to call people idiots on, why this?  Seems to me there are worse ways of blowing your money, and if solar power is something you are passionate about but you live in an apartment building, why is this company so awful? 

I agree with you that from an economic standpoint it's a bad economic investment.  Then again, it's about on par with the returns for a 30 year treasury bond (currently 2.57%).  More risk for certain, but again, I don't think the point of this is total economic return.
Title: Re: solar panel installation
Post by: frugalnacho on April 07, 2015, 09:27:46 AM
True.  I sometimes forget that people are idiots and it is very easy to take advantage of them.
wow.  I mean, just... wow.   Of all the things to call people idiots on, why this?  Seems to me there are worse ways of blowing your money, and if solar power is something you are passionate about but you live in an apartment building, why is this company so awful? 

I agree with you that from an economic standpoint it's a bad economic investment.  Then again, it's about on par with the returns for a 30 year treasury bond (currently 2.57%).  More risk for certain, but again, I don't think the point of this is total economic return.

How is this any different than MMM paying an inflated price for his renewable electricity?  It's all connected to the same grid, and he voluntarily pays more to know his electricity is coming from a renewable resource.  We have a similar program in michigan.  You don't buy a solar panel, but you pay the utility company an inflated price and they use that to increase their renewable (wind, solar) energy production.
Title: Re: solar panel installation
Post by: Roland of Gilead on April 07, 2015, 09:37:23 AM
All of these feel good programs assume zero emissions to create, install, and maintain the solar panels.   I do not think that is the case, so you are not "saving" the earth from 10,000 pounds of added CO2 per panel.

If the company folds after a few years (likely), you will probably have actually added to the global CO2 emissions unless someone else steps in to maintain the farm.


Why not have a crowd funding company that buys rain forest land and places it in a trust so it will not be clear cut.   That would be a long term gain on CO2 levels.

*I should point out that this solar company would not be viable without government subsidy, which is essentially taking resources from one pocket and putting them in another, then pointing out how great a deal this is.   Those resources are then not available for other programs, some of which could also be green.
Title: Re: solar panel installation
Post by: KiloRomeo on April 07, 2015, 09:57:06 AM
All of these feel good programs assume zero emissions to create, install, and maintain the solar panels.   I do not think that is the case, so you are not "saving" the earth from 10,000 pounds of added CO2 per panel.

If the company folds after a few years (likely), you will probably have actually added to the global CO2 emissions unless someone else steps in to maintain the farm.


Why not have a crowd funding company that buys rain forest land and places it in a trust so it will not be clear cut.   That would be a long term gain on CO2 levels.

*I should point out that this solar company would not be viable without government subsidy, which is essentially taking resources from one pocket and putting them in another, then pointing out how great a deal this is.   Those resources are then not available for other programs, some of which could also be green.

Why AREN'T there options like this (or are there?). I've always thought that if I won the lottery I would just start buying land and starting parks.
Title: Re: solar panel installation
Post by: MrFancypants on April 07, 2015, 10:04:25 AM
All of these feel good programs assume zero emissions to create, install, and maintain the solar panels.   I do not think that is the case, so you are not "saving" the earth from 10,000 pounds of added CO2 per panel.

Usually the emissions cost to create/install/maintain is assumed, because it's a cost that all forms of energy production have to pay.  It's not like coal power plants just spring up out of the ground.
Title: Re: solar panel installation
Post by: nereo on April 07, 2015, 10:42:49 AM
All of these feel good programs assume zero emissions to create, install, and maintain the solar panels.   I do not think that is the case, so you are not "saving" the earth from 10,000 pounds of added CO2 per panel.

If the company folds after a few years (likely), you will probably have actually added to the global CO2 emissions unless someone else steps in to maintain the farm.
If the program does fold (and I agree that's a possibility), why wouldn't someone else step in?  The vast majority of the cost is in the construction of the farm (including purchasing the panels).  Once it's up and running the annual costs are negligible.  It would seem to be the perfect business to buy up if the original (cloudsolar) becomes insolvent) - all the profit, almost none of the expenses.  Even better if the takeover company has no financial obligation to pay quarterly checks to the original investors...

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Why not have a crowd funding company that buys rain forest land and places it in a trust so it will not be clear cut.   That would be a long term gain on CO2 levels.
There are companies that attempt to do this - main problem is questions of national sovereignty.    It's hard (if not impossible) for a foreign entity to prevent a government from utilizing its own resource.  Also, not cutting rain-forests wouldn't result in a long term gain on CO2 levels (which I interpret to mean a reduction in atmospheric CO2).  Rainforests aren't carbon sinks... in most cases they actually are a small carbon source.  However, clear-cutting them would release a lot of the stored carbon, perhaps that's what you meant?
All said, I still don't understand why you would support a company that buys rain forests for conservation (and presumably returns nothing to the donors), yet oppose one that creates solar panels with the aim of giving a small subsidy back.

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*I should point out that this solar company would not be viable without government subsidy, which is essentially taking resources from one pocket and putting them in another, then pointing out how great a deal this is.   Those resources are then not available for other programs, some of which could also be green.
Which government subsidy?  There's a lot out there, all designed to help out different projects.  Government dollars also build schools, roads and parks, all of which generate jobs and (ideally) generate more revenue.  How is this any different?
Again, I don't understand your logic that we shouldn't support one project that aims to increase total solar energy output and is green because it might take money away from another project that might also be green.  It's like a small hospital with one surgeon saying we shouldn't operate on one patient because a second one might come along "sometime".
Title: Re: solar panel installation
Post by: sol on April 07, 2015, 12:30:41 PM
The stated expected return (which, according to the website's FAQ, seems to include anticipated government tax credits and incentives) falls short of sol's anticipated return (as outlined earlier in this thread), even before reduction for the company's 20% fee. 

I also have a really good roof for solar panels.  Most homes at my location will generate slightly less power than I do due to shading or angle issues, and I've learned that all the profit is in that last few percent of production.

My bimonthly power bill includes an $11 grid connection fee.  In periods when we use more power than we produce, we pay that fee plus we buy power at 8.5 cents/kWh.  In periods when we make more than we use, they pay us 8.5 cents/kWh and apply the surplus against that $11 fee or our water bill.  So the dollar difference between being a little bit under vs a little bit over turns out to be pretty significant.

Solar update: we're on track to max out the $5k state subsidy this year in only 11 months of production.  We already got the $9720 federal tax credit, and will bank another $900 in direct power costs from either reduced purchases or direct per kwh payments.  So total return in year one is looking like about 48% of my outlay, with years two through six returning 18% of my outlay, and then 2.7% return (just the power costs, no subsidies) every year after that as long as the panels last.  Or more than 2.7% if power costs continue to rise.
Title: Re: solar panel installation
Post by: brooklynguy on April 07, 2015, 01:24:54 PM
My bimonthly power bill includes an $11 grid connection fee.

This is a material tidbit of new information.  $5.50 per month represents a meaningful percentage of the average mustachian's total electric bill.  It barely makes a dent in your sweet financial payback, but for those of us without access to comparably generous state incentive programs a fee like that could nickel and dime us right into the red.
Title: Re: solar panel installation
Post by: sol on April 07, 2015, 01:34:45 PM
My bimonthly power bill includes an $11 grid connection fee.

This is a material tidbit of new information.  $5.50 per month represents a meaningful percentage of the average mustachian's total electric bill.  It barely makes a dent in your sweet financial payback, but for those of us without access to comparably generous state incentive programs a fee like that could nickel and dime us right into the red.

I'm not clear on why it's relevant to the payback schedule calculation.  I pay it because of where I live, no matter how much power I use or produce.  It might as well be a property tax.
Title: Re: solar panel installation
Post by: brooklynguy on April 07, 2015, 02:14:50 PM
I'm not clear on why it's relevant to the payback schedule calculation.  I pay it because of where I live, no matter how much power I use or produce.  It might as well be a property tax.

Oh, I thought you meant it was a fee specifically charged to you as a solar power producer who is connected to the grid (which would not otherwise be charged).  My bad.
Title: Re: solar panel installation
Post by: Uncle Scrooge on May 26, 2015, 11:30:58 AM
I have a couple questions I'm hoping someone could answer for me:

1. Someone mentioned early on that you won't get a check for 30% of the solar panels come tax time. I've always had a refund each year of my working life (I know, I know..I should change my withholdings). If I were to get solar panels (which I'm considering) how would I make sure I get my rebate?

2. Does your homeowner's insurance rate go up? I would guess yes because it's more that could break on your house in the event of a storm. If so, did you factor the increase in rate into your breakeven point?
Title: Re: solar panel installation
Post by: sol on May 26, 2015, 12:15:43 PM
The federal tax rebate for our solar panels was claimed on line 53 of our 1040, residential energy credits. You work through form 5695 to figure the amount, and it includes a provision for carrying forward amounts into future years.

We did not adjust our insurance for solar panels.  Didn't even occur to me.  Not sure they would be covered anyway, I suspect they are viewed more like a water heater or furnace than an addition to your house.

p.s.  Our combined water and power bill for the past two months was $2.25, even after the $70 in combined bullshit customer charges and flat fees.
Title: Re: solar panel installation
Post by: Uncle Scrooge on May 26, 2015, 12:27:13 PM
Man, I am so jealous of that water/electricity bill!

We have an electric stove, water heater, and air conditioner. We would really benefit from solar! Hopefully I can join you guys soon.

For tax purposes, let's say I get 2k a year refund normally and I am due to get 8k in solar rebates. Would I get 10k back next year at tax time? Or would it work differently? I am getting mixed answers when reading different articles online.

Thanks!

Title: Re: solar panel installation
Post by: Uncle Scrooge on May 26, 2015, 12:29:34 PM
Oh wait...I read your response incorrectly. You said you could carry it forward in future years.

Sorry about that!
Title: Re: solar panel installation
Post by: nereo on May 26, 2015, 12:30:25 PM

Our combined water and power bill for the past two months was $2.25, even after the $70 in combined bullshit customer charges and flat fees.
Love hearing your updates Sol!   You are coming up on the year mark now - I'd love to see a breakdown of energy production over that timeframe if you care to share it...

One question I've had is whether you've had to do any cleaning/maintenance on the panels yet? Do dirt/leaves/pollen accumulate on and in between the panels?
Title: Re: solar panel installation
Post by: sol on May 26, 2015, 01:41:08 PM
Love hearing your updates Sol!   You are coming up on the year mark now - I'd love to see a breakdown of energy production over that timeframe if you care to share it...

Bimonthly billing means my full year won't be available until September.  If you think you're impatient, imagine how I feel.

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One question I've had is whether you've had to do any cleaning/maintenance on the panels yet? Do dirt/leaves/pollen accumulate on and in between the panels?

No maintenance yet, but I have my first panel inspection penciled in for July.  My house is on a hill so my roof has no trees above it. I'm expecting to find just windblown pollen and dust, and will just hose everything off.  The rain should be doing a fine job of that in the winters.
Title: Re: solar panel installation
Post by: forummm on May 26, 2015, 03:11:48 PM
I'm super jealous, Sol. This is really cool. Unfortunately, GA doesn't have any solar incentives, so the math isn't quite as good. And I have a east-west roof, so it wouldn't be ideal anyway.
Title: Re: solar panel installation
Post by: Mrs. PoP on May 27, 2015, 05:29:59 PM
With homeowner's insurance, we called to make sure that we didn't need any riders on the policy.  But we've decided to up our coverage level to include replacement value of the solar system at our next renewal. 

Also, is the refund because you paid $0 in taxes or because you overpaid your taxes?  If it's the latter, then you should just get a bigger refund up until you have a $0 tax bill for the year and carry forward beyond that, I think. 
Title: Re: solar panel installation
Post by: sol on May 27, 2015, 07:37:08 PM
Also, is the refund because you paid $0 in taxes or because you overpaid your taxes?  If it's the latter, then you should just get a bigger refund up until you have a $0 tax bill for the year and carry forward beyond that, I think.

I'm in the opposite situation from some people here, in that our annual federal tax liability far exceeds the solar panel rebate amount.  We don't have to worry about carrying forward, because the rebate just wipes out part of this year's tax bill.

When I say "refund" I really mean "reduced tax liability".  We're pretty careful about adjusting our W2 withholding throughout the year to zero out our refund in Feb/March, but how much we pay throughout the year as payroll deductions has absolutely no bearing on what our actual tax liability for the year will be, unless we were to overpay and be due a refund.  We never overpay.

But in general, I think your advice is sound for people who don't normally pay much tax.  Take enough of the refund to wipe out any tax liablity for the year, and carry the rest forward for future years.  In my case it all fit into one year.
Title: Re: solar panel installation
Post by: medinaj2160 on May 27, 2015, 08:13:40 PM
Is there any good forums that I can read to see if is worth getting a Solar System?

I live in South Carolina and I am looking for a system to cover my monthly usage of 600 kWh which will cover our electricity 100% (the average usage per year was 400 kWh and the highest usage was 800 kWh). I saw a couple of systems at Costco but they do not come with batteries; I was thinking about maybe using the Tesla Powerwall to cover my night consumption. 

I am a complete noob at this and I am just doing some research to see if is worth it.
Title: Re: solar panel installation
Post by: Axecleaver on May 28, 2015, 08:12:10 AM
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Why AREN'T there options like this (or are there?). I've always thought that if I won the lottery I would just start buying land and starting parks.
Google "land conservancy." It's very popular here in the rural areas where city folks are encroaching. Under land conservancy rules, you sign a permanent agreement that the land will never be improved, in exchange for property tax benefits. The rider follows the property during sale, and is (mostly) irrevocable. So, if you're a city slicker looking for 100 acres of prime farm land to gaze at on the weekends, you execute this and take it permanently off the tax rolls. The problem is, that shifts the tax burden to the working families in the district. It's a big deal in New York with its high tax rates.

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We did not adjust our insurance for solar panels.  Didn't even occur to me.  Not sure they would be covered anyway
It should be covered as a capital improvement, just like an addition to the house would be. You should probably check your policy though and see if you have replacement coverage or actual cash value coverage (depreciated coverage).

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For tax purposes, let's say I get 2k a year refund normally and I am due to get 8k in solar rebates. Would I get 10k back next year at tax time?
Depends on the rebate and your tax liability. Most solar incentives are structured as tax credits. A tax credit allows you to reduce your taxes to zero, and may be carried forward into future years until it's all used up. A tax rebate can give you money back after your taxes are reduced to zero (like the incorrectly named "earned income tax credit" which is actually a rebate). What you get back at tax time is a function of: how much you owe (tax liability) - how much you paid (withholding).

Here's a page that talks about the various federal solar credits available: http://energy.gov/savings and another for state and local incentives: http://www.dsireusa.org/
Title: Re: solar panel installation
Post by: RoadLessTravelled on May 28, 2015, 08:41:54 AM
A program in Ontario, Canada is doing well with a no cost to the homeowner installation setup.  It is government backed and there is no question that it is legit and all as advertised.
http://pureenergies.com/ca/free-solar-panels-program/
Title: Re: solar panel installation
Post by: Uncle Scrooge on May 28, 2015, 08:48:50 AM
With homeowner's insurance, we called to make sure that we didn't need any riders on the policy.  But we've decided to up our coverage level to include replacement value of the solar system at our next renewal. 

Also, is the refund because you paid $0 in taxes or because you overpaid your taxes?  If it's the latter, then you should just get a bigger refund up until you have a $0 tax bill for the year and carry forward beyond that, I think.

That's good advice for homeowner's!

As for our taxes, both my wife and I claim 0 dependents. We overpay each year and then get it back at tax time. I know we should change our withholdings, but I'm so used to the way we've been doing it and it's nice to get that big check each year.
Title: Re: solar panel installation
Post by: NaturallyHappier on May 28, 2015, 07:11:47 PM
Regarding insurance for solar...I checked withmy insurance company when I had the panels installed and the confirmed that they were covereed with no increase in the rate even with the panels being located 250 feet behind the house on pole mounts.  I had a lightning strike on the panels two years ago and my insurance paid to replace 3 panels and one inverter.
Title: Re: solar panel installation
Post by: sol on August 26, 2015, 03:29:42 AM
Checking back into this thread...

It's been just about one year since my solar panels went up.  Over that time, our system has generated more power than we have used by an average of $56 per month.  So in addition to reducing our power bills to zero, we're actually selling $56/month worth of power to the utility company after connection charges.  That's on top of the $5000/year incentive payments.

In the chart below you see our total utility spending by category.  The blue line is our monthly gas bill, which peaks in the winter because we have gas heat.  The red line and the blue stars are fixed costs for sewer and garbage service.  Power (green triangles) and water (purple circles) are billed together bimonthly, and are roughly offsetting each other, as we use more water in the summers when our solar panels are making more power, and we use less water in the rainy winters when our panels make less power. 

The orange line is our total utility bill spending for my family of five in a 2300 sqft house, and averaged $151/month.

The solar panels generates a little over 9200 kWh in 50 weeks of the annual cycle, since they weren't online for the first two weeks.  That's significiantly more than the 7500 kWh we were expecting.  They went live July 30th and our billing cycle starts on the 14th of each month, so that first month of data shown in the graph includes two weeks of an 8 week billing cycle without solar panels.

Overall I'm pretty happy with the performance.  We're just about exactly maxing out our $5000/year state production incentives with our 28 panels.  The system has been entirely maintenance free, other than hosing it off once this summer when it hadn't rained for a while.  The neighbors ask about it periodically, but so far no one else has installed them.
Title: Re: solar panel installation
Post by: nereo on August 26, 2015, 06:35:50 AM

It's been just about one year since my solar panels went up.  Over that time, our system has generated more power than we have used by an average of $56 per month.  So in addition to reducing our power bills to zero, we're actually selling $56/month worth of power to the utility company after connection charges.  That's on top of the $5000/year incentive payments.
...
The solar panels generates a little over 9200 kWh in 50 weeks of the annual cycle, since they weren't online for the first two weeks.  That's significiantly more than the 7500 kWh we were expecting. 
...but, but, but... solar is just too inefficient in the cloudy PNW!  It can't be done!

seriously, thanks for this thread.  I'm curious if you have a graph of power output vs time. 
I do have one question though:  when the panels are rated at 270W each, is that the maximum amount of power one panel can produce on a very sunny day, or an average, or what....?  Can a panel ever produce more than it's rated power output?

Perhaps after a full year's data some of your neighbors will be sold on installing their own solar. 
Title: Re: solar panel installation
Post by: nawhite on August 26, 2015, 07:37:59 AM
... 
I do have one question though:  when the panels are rated at 270W each, is that the maximum amount of power one panel can produce on a very sunny day, or an average, or what....?  Can a panel ever produce more than it's rated power output?


That number is the amount it would generate if the panels are kept cool (usually cooler than they get on top of your roof in the sun) and the sunlight is uniformly intense and and sun is directly overhead of the panels. Generally it is the absolute max you'll ever see but theoretically, if you're at a high elevation (so there is less air to get in the way of the sun), a low latitude (so you're closer to the sun) and your panels track the sun on a pole (so the sun is directly overhead) in a windy area (so the panels stay cool) with brand new panels, then yes you may see a couple percentage points greater than the rated capacity. Generally on a roof, I'd expect to see right around 100% of rated capacity for only a couple minutes a day on the sunniest days.
Title: Re: solar panel installation
Post by: nereo on August 26, 2015, 08:08:16 AM
... 
I do have one question though:  when the panels are rated at 270W each, is that the maximum amount of power one panel can produce on a very sunny day, or an average, or what....?  Can a panel ever produce more than it's rated power output?


That number is the amount it would generate if the panels are kept cool (usually cooler than they get on top of your roof in the sun) and the sunlight is uniformly intense and and sun is directly overhead of the panels. Generally it is the absolute max you'll ever see but theoretically, if you're at a high elevation (so there is less air to get in the way of the sun), a low latitude (so you're closer to the sun) and your panels track the sun on a pole (so the sun is directly overhead) in a windy area (so the panels stay cool) with brand new panels, then yes you may see a couple percentage points greater than the rated capacity. Generally on a roof, I'd expect to see right around 100% of rated capacity for only a couple minutes a day on the sunniest days.
thanks for that explanation.  exactly what i was looking for.
Title: Re: solar panel installation
Post by: b4u2 on August 26, 2015, 08:56:31 AM
If Iowa had incentives I would consider it but we don't. How ever I heard a person I kinda know has them installed on his house so I need to make time to go and check them out. He only lives about a mile from me but he's retired and 5 minutes won't give either of us enough time to talk about them lol
Title: Re: solar panel installation
Post by: nereo on August 26, 2015, 09:08:42 AM
If Iowa had incentives I would consider it but we don't. How ever I heard a person I kinda know has them installed on his house so I need to make time to go and check them out.
Well one thing that you do have in Iowa over Sol's PNW is much better solar radiance levels.  You will be able to harness more power with fewer panels.  The average cost of electricity in Iowa is about 10% more than in Washington, which helps too. 
The lack of incentives is a major blow against, but you still may want to price out the ROI for various-sized solar installations in your area.
Title: Re: solar panel installation
Post by: b4u2 on August 26, 2015, 10:27:05 AM
If Iowa had incentives I would consider it but we don't. How ever I heard a person I kinda know has them installed on his house so I need to make time to go and check them out.
Well one thing that you do have in Iowa over Sol's PNW is much better solar radiance levels.  You will be able to harness more power with fewer panels.  The average cost of electricity in Iowa is about 10% more than in Washington, which helps too. 
The lack of incentives is a major blow against, but you still may want to price out the ROI for various-sized solar installations in your area.

I'm hoping the other guy near me already did the leg work so that I can pick his brain.
Title: Re: solar panel installation
Post by: nereo on August 26, 2015, 11:28:48 AM
If Iowa had incentives I would consider it but we don't. How ever I heard a person I kinda know has them installed on his house so I need to make time to go and check them out.
Well one thing that you do have in Iowa over Sol's PNW is much better solar radiance levels.  You will be able to harness more power with fewer panels.  The average cost of electricity in Iowa is about 10% more than in Washington, which helps too. 
The lack of incentives is a major blow against, but you still may want to price out the ROI for various-sized solar installations in your area.

I'm hoping the other guy near me already did the leg work so that I can pick his brain.
lol, i hope he did - would be interested in hearing what you learn, if only because i'm curious how the equation changes state-to-state.  We don't know where we'll be living next.
We wanted to install solar PVs when we re-did our roof, but since we're living in Quebec presently the math was against us.  We have some of the cheapest electricity rates (as low as 5.68/kwh), poor solar radiance (about 40% of what the coastal PNW gets, and 1/3 what Cedar Rapids receives), very high sales tax (15%) plus no good incentives and no way of getting money back for overproduction (only credits at 5.68/kwh).  Our most optimistic payback period was still ~15 years.
Title: Re: solar panel installation
Post by: monarda on August 26, 2015, 04:08:42 PM
nereo,  FYI
this web site summarizes solar-friendliness in various states
solarpowerrocks.com
Title: Re: solar panel installation
Post by: nereo on August 26, 2015, 04:16:46 PM
nereo,  FYI
this web site summarizes solar-friendliness in various states
solarpowerrocks.com
thanks for the link!
Title: Re: solar panel installation
Post by: PatronWizard11 on August 26, 2015, 04:39:38 PM
I am almost in the exact same situation as you are except my state doesn't have any laws to prevent HOA's to stop home owners from installing solar.  They denied my first application but I do admit, it wasn't turned in with everything I should have turned out in with, like the cad drawings, very detailed explanation of the project, the panel specs, etc.  So we waited a week and took a very good attempt to submit an application they couldn't deny. 

If they deny me again... I quit lol
Title: Re: solar panel installation
Post by: Abe on August 26, 2015, 04:43:52 PM
What is your all's opinion of home battery systems (like Tesla's product, but also conventional battery arrays)? I'm considering installing a solar system in 3-4 years when we finally settle down. Money / return on investment doesn't matter to me as much as reliability. Other than maintenance costs, is there any downside to having a battery array?
Title: Re: solar panel installation
Post by: nereo on August 26, 2015, 05:02:10 PM
What is your all's opinion of home battery systems (like Tesla's product, but also conventional battery arrays)? I'm considering installing a solar system in 3-4 years when we finally settle down. Money / return on investment doesn't matter to me as much as reliability. Other than maintenance costs, is there any downside to having a battery array?
As I understand it, there are almost no maintenance costs except swapping out the cells every decade or so (at least for the Tesla-style build-for-end-consumers)
The major drawback is that they're incredibly expensive for something that will be used only sporadically.  Typically when you are on-the-grid you have a surplus of energy during the daytime which you sell back to the power company, and then you draw power from the grid during the evening or when it is overcast/rainy and you have a large power draw.
If you want to go completely off-grid, then a battery pack is very useful.  There are also many DIY methods that rely on golf-cart battery arrays (or similar), but those tend to require a high level of expertise and can be very cumbersome to have in your home, and require swapping out the batteries more frequently than (supposedly) what Tesla is offering up.

The cheapest solution for the occasional black-out remains a gas-powered portable generator.  For ~$1k you can buy a generator that will put out 5kw-9kw and consume roughly a gallon per hour of gasoline.  Sadly, unless you need to use the generator every week for several hours it's unlikely you will ever recoup the cost of a whole-home battery storage system.  But... on the plus side, battery storage systems are silent.
Title: Re: solar panel installation
Post by: nawhite on August 27, 2015, 07:16:54 AM
What is your all's opinion of home battery systems (like Tesla's product, but also conventional battery arrays)? I'm considering installing a solar system in 3-4 years when we finally settle down. Money / return on investment doesn't matter to me as much as reliability. Other than maintenance costs, is there any downside to having a battery array?
As I understand it, there are almost no maintenance costs except swapping out the cells every decade or so (at least for the Tesla-style build-for-end-consumers)
The major drawback is that they're incredibly expensive for something that will be used only sporadically.  Typically when you are on-the-grid you have a surplus of energy during the daytime which you sell back to the power company, and then you draw power from the grid during the evening or when it is overcast/rainy and you have a large power draw.
If you want to go completely off-grid, then a battery pack is very useful.  There are also many DIY methods that rely on golf-cart battery arrays (or similar), but those tend to require a high level of expertise and can be very cumbersome to have in your home, and require swapping out the batteries more frequently than (supposedly) what Tesla is offering up.

The cheapest solution for the occasional black-out remains a gas-powered portable generator.  For ~$1k you can buy a generator that will put out 5kw-9kw and consume roughly a gallon per hour of gasoline.  Sadly, unless you need to use the generator every week for several hours it's unlikely you will ever recoup the cost of a whole-home battery storage system.  But... on the plus side, battery storage systems are silent.

I've been doing a lot of planning for an off grid RV solar setup and all of what you said is true. One of the biggest issues with home battery systems for off grid use is sizing the home inverter. The inverter is the piece of equipment which converts the DC energy you get out of the battery bank (or out of your solar panels in a grid tied setup) into AC energy for your outlets. As inverters go up in maximum output, the cost goes up exponentially. So if you expect to use your house normally, you might be running the air conditioner, the electric clothes dryer, a vacuum cleaner and all the normal household things. All of a sudden you need an inverter sized for >7KW which approach being as expensive as the battery bank. With grid tie systems, you only need to size the inverter for the maximum output of your solar panels, for an off grid/battery backup system, you need to size the inverter for the maximum usage of the house which is usually much higher; especially if you need to run AC (1.5-4kw) and any other major electric appliances like a water heater(2kw), clothes dryer(2-5kw), stove 1.5-3kw), microwave (1.5kw), hair dryer (1.8kw), vacuum cleaner (0.8-1.8kw) etc.

For instance, I have a grid tie solar system with a 3.0 KW inverter that cost about $1200. My maximum instantaneous home usage is up around 10 KW (AC, clothes dryer, electric stove, fridge cycled on, a couple computers and lights). A similar quality 8KW inverter costs around $4,500.
Title: Re: solar panel installation
Post by: b4u2 on August 31, 2015, 01:55:39 PM
I got to talk with the guy a little bit while at my kids football game. His Grandson and mine go to school and are both on the same football team. Apparently Iowa does have a solar rebate. I'll get with him again to find out more details. I thought he said Iowa has $5000 in rebates and a federal rebate of $9000. The only thing I don't like is it is net free metering. So if he over produces he doesn't get a kick back the electric company gets to keep it for free. So he said he installed enough to make him 85% efficient. He also used the micro inverters which I had researched a ton before I gave up my pursuit of solar.
Title: Re: solar panel installation
Post by: dragoncar on August 31, 2015, 03:59:12 PM
A lot of utilities are changing up their rate schedules and metering agreements.  Hopefully Sol gets grandfathered in, but it's not a sustainable model for utilities and non-solar users to bear the entire grid cost.
Title: Re: solar panel installation
Post by: nereo on August 31, 2015, 07:58:15 PM
Ok, follow up question....
Is the conversion efficiency more or less the same regardless of the current solar irradiance? For example, in optimal conditions Sol's panels will produce ~270w each.  If the irradiance drops by 50% because a cloud goes y, does the efficiency drop by an equivalent amount?  Or is it non-linear?
Title: Re: solar panel installation
Post by: Abe on September 01, 2015, 01:52:03 PM
The efficiency (energy output / energy input) should not vary with the amount of input within normal parameters. However, it does decrease with high input levels (i.e. using mirrors to concentrate incoming sunlight), mostly due to increased thermal energy affecting the efficiency of the cell. You may be asking if the energy output drops in a linear fashion, and that is generally true within normal operating conditions.


Concerns about the the utilities' price gouging for grid maintenance is one of the reasons I would consider an off-grid system. Grid maintenance fees should already be considered in the baseline utility cost and it's not clear to me how solar power producers are resulting in increased capital costs. However it seems that most public utility commissions are not allowing it (Nevada is a recent example), mostly because the utilities cannot answer my question clearly.
Title: Re: solar panel installation
Post by: dragoncar on September 01, 2015, 02:16:44 PM


Concerns about the the utilities' price gouging for grid maintenance is one of the reasons I would consider an off-grid system. Grid maintenance fees should already be considered in the baseline utility cost and it's not clear to me how solar power producers are resulting in increased capital costs. However it seems that most public utility commissions are not allowing it (Nevada is a recent example), mostly because the utilities cannot answer my question clearly.

You generate 5 excess kWh during the day and put it on the grid.  You draw 5kwh from the grid at night.  Net usage is zero, no bill.  You used the grid for free, but the grid needs to be maintained.  You don't see why that is a problem in the long run?  I don't have a problem with this arrangement when they were trying to incentivize solar power and 10 people did it.  It will be a major problem if 50% of people do it...
Title: Re: solar panel installation
Post by: Abe on September 03, 2015, 02:44:29 PM
I'm not sure how your electricity bill is itemized, but mine separates the cost of maintenance (baseline carriage fee everyone pays) from the electricity used (energy fee, which may be billed from a different utility than the one providing the actual grid connection). In this scenario, paying more just for having a solar array isn't fair.
Title: Re: solar panel installation
Post by: sol on September 03, 2015, 08:39:36 PM
Agreed, I pay the same flat fee for having a grid connection as every other user.  In my case, the panels produce so much that the utility's purchase price of my surplus wipes out my grid connection fee too, but it still shows up on every bill.  They're getting more free power from me than the cost of my grid usage.
Title: Re: solar panel installation
Post by: dragoncar on September 04, 2015, 03:13:15 AM
Agreed, I pay the same flat fee for having a grid connection as every other user.  In my case, the panels produce so much that the utility's purchase price of my surplus wipes out my grid connection fee too, but it still shows up on every bill.  They're getting more free power from me than the cost of my grid usage.

That's a good thing, but most states aren't like that.  Do you think your flat fee covers "your portion" of the grid maintenance?  Obviously "your portion" is up for debate -- should the costs be split on a per household basis, per capita, usage based, etc., but I'm curious to know if you think you are a subsidizer, being subsidized, or just right.
Title: Re: solar panel installation
Post by: b4u2 on September 04, 2015, 06:31:48 AM
Executive Summary - cash purchase

Gross cost:   $46,165
Iowa Solar Energy System Tax Credit: Residential 60% of Fed. Tax Credit ($5k max)   -$5,000  link
Federal Tax Credit (30% of Net Cost at Installation)   -$12,350  link
Net Cost of System after rebates and incentives:   $28,815
 
Pay Back Time:   12.34 years
Internal Rate of Return (IRR) on Investment:   8.1%

How the hell am I supposed to afford that? Just curious how others find a way to pay for the system? I would love to go solar but I don't have another $46k laying around now. WHat if I don't stay in this house till I retire?
Title: Re: solar panel installation
Post by: zephyr911 on September 04, 2015, 07:32:07 AM
You generate 5 excess kWh during the day and put it on the grid.  You draw 5kwh from the grid at night.  Net usage is zero, no bill.  You used the grid for free, but the grid needs to be maintained.  You don't see why that is a problem in the long run?  I don't have a problem with this arrangement when they were trying to incentivize solar power and 10 people did it.  It will be a major problem if 50% of people do it...
Incentives would have to taper off in the long run. I'm a big supporter of solar but obviously the math doesn't work in an end-state scenario where most/all ratepayers have net negative bills. The cost of the grid connection will go up, or incentives will drop, or both. But that's OK for the solar industry, because the cost of the systems is still falling steadily. In fact, the more expensive off-grid option (batteries and all) - which is already cheaper than legacy grid power in a few high-cost areas, like HI - will undercut the cost of grid power in most areas within 5-10 years.

Smart utilities will work out business models that sell customers on the added value of the grid tie (reliability, economies of scale via central storage vs. distributed, etc). Others may fail and require bailouts. The entire sector had its credit downgraded (http://www.businessinsider.com/barclays-downgrades-utilities-on-solar-threat-2014-5) over these concerns, lest you think I'm being dramatic. ;)

How the hell am I supposed to afford that? Just curious how others find a way to pay for the system? I would love to go solar but I don't have another $46k laying around now. WHat if I don't stay in this house till I retire?
These guys do up to $40K. (https://www.admiralsbank.com/renewable-energy-lending) I was going to use them for my PV install but USAA (silly them) offered me a year, no advance fee, no interest, on a card with a very high limit (had it since 2000). I parked the cost there and am undecided on what's next - pay down gradually, roll into another 0% card, or move to a HELOC.

Re: your 2nd question, you don't have to stay forever. Research indicates you'll recoup about 40% of the added cost on a typical home sale, so staying for 60% of the payback period is a good idea. I am almost definitely not staying that long myself, but I did it anyway on principle. (dirty hippy idealist, blah blah blah)
Title: Re: solar panel installation
Post by: thd7t on September 04, 2015, 07:38:30 AM
Executive Summary - cash purchase

Gross cost:   $46,165
Iowa Solar Energy System Tax Credit: Residential 60% of Fed. Tax Credit ($5k max)   -$5,000  link
Federal Tax Credit (30% of Net Cost at Installation)   -$12,350  link
Net Cost of System after rebates and incentives:   $28,815
 
Pay Back Time:   12.34 years
Internal Rate of Return (IRR) on Investment:   8.1%

How the hell am I supposed to afford that? Just curious how others find a way to pay for the system? I would love to go solar but I don't have another $46k laying around now. WHat if I don't stay in this house till I retire?
What size system are you looking at?  This seems huge to me.  In terms of paying for the system, you could investigate a HELOC.  It would lower your rate of return (probably to around 5%), but a 5% guaranteed return is pretty good.  Clearly, if you don't think you'll stay in the house, it might not be so good, unless the panels increase your home value substantially.  In addition, should energy prices increase, you may see your rate of return increase as well.
Title: Re: solar panel installation
Post by: nereo on September 04, 2015, 07:45:55 AM
Executive Summary - cash purchase

Gross cost:   $46,165
Iowa Solar Energy System Tax Credit: Residential 60% of Fed. Tax Credit ($5k max)   -$5,000  link
Federal Tax Credit (30% of Net Cost at Installation)   -$12,350  link
Net Cost of System after rebates and incentives:   $28,815
 
Pay Back Time:   12.34 years
Internal Rate of Return (IRR) on Investment:   8.1%

How the hell am I supposed to afford that? Just curious how others find a way to pay for the system? I would love to go solar but I don't have another $46k laying around now. WHat if I don't stay in this house till I retire?

Curious how long it typically takes for the federal and local rebates to come back.  If it's within 12 months that makes it a lot more feasible. 
Agree with Zypher911 that a low interest, short-term loan might make the most sense.  Personally I'd probably use my HELOC, but as I mentioned earlier my payback period and cost is far less rosy than the $46k/12.34 years that you have. 

Also - b4us - did you get a breakdown on the costs?  e.g. how much of that $46k was for the panels, the inverters, installation, grid tie-in etc?  Sol did a really nice breakdown for his.
Title: Re: solar panel installation
Post by: zephyr911 on September 04, 2015, 08:03:20 AM
Yeah, that is a big system. Mine was only $12K + associated costs (tree work, upgrading electrical service to new code, etc).

Nereo, the federal tax credit applies for the calendar year, so generally within 15 months, worst case. I got my system installed in June, activated in July, and will file for the credit (negating 80% of my taxes for this year) around the end of January - that 7-month period is probably about average since mine was mid-year.

That Admirals program I linked to includes an option to get 30% of the cost interest-free for up to 18 months, with the understanding that you'll get the full 30% federal credit back on taxes and use it to repay that portion of the loan.

Other incentives are often faster. I got a local (TVA) rebate of $1000 within weeks of activation.
Title: Re: solar panel installation
Post by: monarda on September 04, 2015, 08:20:22 AM
Curious if others have done solar the way I plan to: small system now and then expand later.

In 2011, we installed a small (1.92 kW) system (on a rental), tied to grid, all the wiring set up for future expansion. Numbers: roughly $12K system - $6.5K total incentives + $1.8K prep for expansion= $7.3K in so far) Expansion is designed. We will just need racks, 8 or 9 more panels, and microinverters.
Now we're waiting a couple of years for our reserves to reach a level where we can afford more panels. Plus the price will go down.
Title: Re: solar panel installation
Post by: forummm on September 04, 2015, 08:42:41 AM
Agreed, I pay the same flat fee for having a grid connection as every other user.  In my case, the panels produce so much that the utility's purchase price of my surplus wipes out my grid connection fee too, but it still shows up on every bill.  They're getting more free power from me than the cost of my grid usage.

That's a good thing, but most states aren't like that.  Do you think your flat fee covers "your portion" of the grid maintenance?  Obviously "your portion" is up for debate -- should the costs be split on a per household basis, per capita, usage based, etc., but I'm curious to know if you think you are a subsidizer, being subsidized, or just right.

Given that they are also paying Sol something outrageously high like 54 cents per kWh for the solar juice, he's being subsidized pretty substantially by the other grid customers. As far as the grid connection fee, he's probably not being subsidized there--yet (although the math is hard to work out). That only starts to become an issue when say a double-digit percent of the total grid load is being provided by solar and the utilities have to do more serious load management and even storage (if the percent gets very high).
Title: Re: solar panel installation
Post by: zephyr911 on September 04, 2015, 09:34:28 AM
Curious if others have done solar the way I plan to: small system now and then expand later.

In 2011, we installed a small (1.92 kW) system (on a rental), tied to grid, all the wiring set up for future expansion. Numbers: roughly $12K system - $6.5K total incentives + $1.8K prep for expansion= $7.3K in so far) Expansion is designed. We will just need racks, 8 or 9 more panels, and microinverters.
Now we're waiting a couple of years for our reserves to reach a level where we can afford more panels. Plus the price will go down.
Yes. I bought 3kW and will most likely double it in a year or two. Not sure though... depends on making up our minds how long we're living here. My local conditions mean shit ROI (like 3-4%) so it was more of a statement buy than anything else.
Title: Re: solar panel installation
Post by: Cadman on September 04, 2015, 09:44:49 AM
I've been following this thread as I've thought about putting in such a system one day, and getting my feet wet on a new building I put up that's too far from the grid but where light during the winter hours would be nice. For that, a couple panels and a battery would suffice.

The way Sol did it is really the only way to go if you want to get ahead financially. Even if you value your time at $0, you'll never break-even on a battery system despite claims to the contrary.

A few random observations:

In our locality, the power company is starting a program called 'Simple Solar'. You pay up front buying a number of credits, and they'll build a unitized solar garden for the community. the more people that buy in, the more panels they'll add. You then get a credit discount on each month's bill, and they handle all costs and maintenance associated with it. I think the break-even point is 10 years out.

I know a retired engineer that put in a massive pole-mount system the last couple of years. His goal was zero energy cost. Of course he heats more efficiently with LP, but the additional panels he installed offset that LP cost.

You can build a more efficient system with series strings of panels to get to a higher voltage and feed that to a smart controller. However, he discovered that despite the panels all having the same rating, under identical conditions, some were worse performers than others. The worst were pulled out and not used because they drag down the entire chain; he moved others around (electrically) to balance his inputs. 

Phantom Loads- Before he spent a dime on the panels, he used a clamp-type ammeter at his breaker panel to find all phantom loads. For things that draw power 24/7, like a thermostat transformer or a doorbell transformer, he'd combine those into one source. For things around the house that drew similar power (wall-warts) those got a special wire run to a toroidal low-loss xformer in the basement.  With those ammeter numbers and a pocket calculator you can find out pretty quick how much you're throwing away.

If you live in a snowy climate, take that into consideration. If the panels are reachable, you'll need to sweep them off occasionally or output will drop. I think I could handle that kind of work post-FIRE. ; )
Title: Re: solar panel installation
Post by: b4u2 on September 04, 2015, 10:14:18 AM
I used http://www.solar-estimate.org/ and they only asked what my average bill was. For some reason this summer our bill has been insanely high. The company they suggest is Able Energy Co. They claim they will come and do a better review of the estimate and explain all the costs.

I assume I would have to pay the 46k with a loan? I have no idea how the tax credits work. DO I even pay enough in taxes for this to work? I have no clue. I guess I would have them come do a better estimate and then figure the rest out once I have a better number for cost. I suppose if my electric bill went from about $180 a month to maybe $0 this would pay for the system? The electricity isn't free since I would still have to pay for the system so the cost is diverted? Doesn't give me that "happy feeling". Yeah I would be "green" but still spending the same amount of dollars?
Title: Re: solar panel installation
Post by: zephyr911 on September 04, 2015, 11:14:32 AM
I used http://www.solar-estimate.org/ and they only asked what my average bill was. For some reason this summer our bill has been insanely high. The company they suggest is Able Energy Co. They claim they will come and do a better review of the estimate and explain all the costs.

I assume I would have to pay the 46k with a loan? I have no idea how the tax credits work. DO I even pay enough in taxes for this to work? I have no clue. I guess I would have them come do a better estimate and then figure the rest out once I have a better number for cost. I suppose if my electric bill went from about $180 a month to maybe $0 this would pay for the system? The electricity isn't free since I would still have to pay for the system so the cost is diverted? Doesn't give me that "happy feeling". Yeah I would be "green" but still spending the same amount of dollars?
If you used your recent (seasonal) average, it probably overstated the system size required, which inflates the cost. However, when you say your bill has gone high recently, all kinds of alarm bells go off. You probably have an insulation problem, a crack or some other kind of leak, OR your AC is not functioning at full efficiency.

Since it sounds like the PV system may be a bridge too far, and you want to do green things with higher ROI, I would strongly suggest you put PV on the back burner, and drop a few hundred bucks on a professional energy audit and an AC checkup. Chances are you'll see vastly higher bang for your buck on those things.

http://www.mrmoneymustache.com/2015/03/25/cut-your-power-bill/
http://www.mrmoneymustache.com/2013/10/15/when-energy-saving-becomes-an-emergency/
http://www.mrmoneymustache.com/2014/05/01/beating-the-stock-market-with-diy-insulation/
http://www.mrmoneymustache.com/2011/05/10/ill-show-you-my-electricity-bill-if-you-show-me-yours/
Title: Re: solar panel installation
Post by: nawhite on October 08, 2015, 05:53:48 AM
Executive Summary - cash purchase

Gross cost:   $46,165
Iowa Solar Energy System Tax Credit: Residential 60% of Fed. Tax Credit ($5k max)   -$5,000  link
Federal Tax Credit (30% of Net Cost at Installation)   -$12,350  link
Net Cost of System after rebates and incentives:   $28,815
 
Pay Back Time:   12.34 years
Internal Rate of Return (IRR) on Investment:   8.1%

How the hell am I supposed to afford that? Just curious how others find a way to pay for the system? I would love to go solar but I don't have another $46k laying around now. WHat if I don't stay in this house till I retire?

How many kwh do you average per month? We average about 450 and are putting in a 5.2 kw system. Total cost  of the  system we are putting in this fall is about $14,000. After rebates we will be out of pocket about $4,000. We are also in Iowa. I think you may need to cut your electricity consumption first.

Yeah if your usage is high enough you need $46k in solar to offset it all, you need to invest in decreasing your usage first. Much more efficient (or gas) clothes dryer, better fridge (or going down to just one fridge), ways to decrease your home AC use like window awnings, sealing windows and doors, better insulation etc. When your usage is that high, every dollar you spend on decreasing demand will have a faster payback than solar.
Title: Re: solar panel installation
Post by: 2lazy2retire on October 08, 2015, 06:46:53 AM
Executive Summary - cash purchase

Gross cost:   $46,165
Iowa Solar Energy System Tax Credit: Residential 60% of Fed. Tax Credit ($5k max)   -$5,000  link
Federal Tax Credit (30% of Net Cost at Installation)   -$12,350  link
Net Cost of System after rebates and incentives:   $28,815
 
Pay Back Time:   12.34 years
Internal Rate of Return (IRR) on Investment:   8.1%

How the hell am I supposed to afford that? Just curious how others find a way to pay for the system? I would love to go solar but I don't have another $46k laying around now. WHat if I don't stay in this house till I retire?

How many kwh do you average per month? We average about 450 and are putting in a 5.2 kw system. Total cost  of the  system we are putting in this fall is about $14,000. After rebates we will be out of pocket about $4,000. We are also in Iowa. I think you may need to cut your electricity consumption first.

Yeah if your usage is high enough you need $46k in solar to offset it all, you need to invest in decreasing your usage first. Much more efficient (or gas) clothes dryer, better fridge (or going down to just one fridge), ways to decrease your home AC use like window awnings, sealing windows and doors, better insulation etc. When your usage is that high, every dollar you spend on decreasing demand will have a faster payback than solar.

Why is everyone quoting the 46k figure when the net cost is 28k, or am I not understanding this - do you have to wait years for the incentives to kick in?
Title: Re: solar panel installation
Post by: nawhite on October 08, 2015, 07:10:30 AM
Executive Summary - cash purchase

Gross cost:   $46,165
Iowa Solar Energy System Tax Credit: Residential 60% of Fed. Tax Credit ($5k max)   -$5,000  link
Federal Tax Credit (30% of Net Cost at Installation)   -$12,350  link
Net Cost of System after rebates and incentives:   $28,815
 
Pay Back Time:   12.34 years
Internal Rate of Return (IRR) on Investment:   8.1%

How the hell am I supposed to afford that? Just curious how others find a way to pay for the system? I would love to go solar but I don't have another $46k laying around now. WHat if I don't stay in this house till I retire?

How many kwh do you average per month? We average about 450 and are putting in a 5.2 kw system. Total cost  of the  system we are putting in this fall is about $14,000. After rebates we will be out of pocket about $4,000. We are also in Iowa. I think you may need to cut your electricity consumption first.

Yeah if your usage is high enough you need $46k in solar to offset it all, you need to invest in decreasing your usage first. Much more efficient (or gas) clothes dryer, better fridge (or going down to just one fridge), ways to decrease your home AC use like window awnings, sealing windows and doors, better insulation etc. When your usage is that high, every dollar you spend on decreasing demand will have a faster payback than solar.

Why is everyone quoting the 46k figure when the net cost is 28k, or am I not understanding this - do you have to wait years for the incentives to kick in?

I quoted that because I always mentally think of my 3.2KW system as costing $12k not $8k after incentives but that is because I have to wait 13 months from after I paid for the system until I file my taxes (paid January 2015, file February-ish 2016). Though even at $28k the same thing applies, decrease demand before you look at solar, it's usually a better payback.
Title: Re: solar panel installation
Post by: b4u2 on October 08, 2015, 09:13:43 AM
I'll try copy and paste to see how this chart works.

Yeah that didn't work. I'll try this
Title: Re: solar panel installation
Post by: nawhite on October 08, 2015, 01:18:23 PM
I'll try copy and paste to see how this chart works.

Yeah that didn't work. I'll try this

Your usage is around 5 times mine. 2 people living in a 1100 sq ft house. Electric stove and electric clothes dryer, gas heat and hot water. We decided to go with solar because we were basically out of other more cost effective home improvements. Sounds like you need to do an energy audit long before you even think about solar.

LED light bulbs have a faster payback than solar panels. Depending on where you live, attic insulation usually has a much faster payback than solar. Weather stripping your windows and doors almost always has a faster payback than solar. Setting your thermostat one degree warmer in the summer has an infinitely faster payback than solar because the cost is $0. Pay for an energy auditor from your area and listen to their advice.
Title: Re: solar panel installation
Post by: nereo on October 08, 2015, 02:59:04 PM
I'll try copy and paste to see how this chart works.

Yeah that didn't work. I'll try this

Your usage is around 5 times mine. 2 people living in a 1100 sq ft house.... Pay for an energy auditor from your area and listen to their advice.
Just to add on... Many municipalities offer either free energy audits or rebates for energy audits. 
Even if you have to pay out of pocket with no reimbursement the cost is usually only a couple hundred dollars... which will can be paid off through energy savings much faster than solar.
Title: Re: solar panel installation
Post by: b4u2 on October 09, 2015, 04:44:19 PM
I'll check around. We are a household of 5 and up to 7 depending on the time of year. This house was built in 2003. Electric dryer, gas heat, electric tankless water heater, dishwasher, electric stove, fridge, small freezer, lots of small stuff.
Title: Re: solar panel installation
Post by: monarda on October 10, 2015, 08:47:51 AM
With 7 people, I wouldn't be surprised if it's your tankless water heater. Our biggest electricity hog is our electric hot water heater (40 gal tank).

We monitored our electric usage- I posted about it here on this thread.  (http://forum.mrmoneymustache.com/real-estate-and-landlording/i-pay-my-tenants-power-bill-how-can-i-get-them-to-be-thrifty/msg803680/#msg803680)

If you ever come to Madison and want to take our TED to borrow for a couple of weeks, you're welcome to.
Title: Re: solar panel installation
Post by: nawhite on October 10, 2015, 11:14:43 AM
With 7 people, I wouldn't be surprised if it's your tankless water heater. Our biggest electricity hog is our electric hot water heater (40 gal tank).

That would be my guess too. Heating water (or really anything) with electricity is really expensive and fairly inefficient if you don't use a heat pump. Though with heat pumps, remember that the heat still has to come from somewhere. In homes which have the heat on more than the AC, heat pump water heaters are just inefficient ways to heat your water with gas. (gas heats air, heat pump takes heat from air and moves it to water = gas heats water). In your case, using solar water heating panels would probably be far more cost effective at decreasing your bills and payback way faster than solar photovoltaic panels.
Title: Re: solar panel installation
Post by: b4u2 on October 12, 2015, 12:43:50 PM
I installed that water heater back in January but my bill only started increasing in July. I also realized I have a huge ($300+) credit on my electric bill now. I wonder if they made a mistake and instead of telling me about it they just credited my account. I might have to dig into this credit and increased usage a little more now that I looked at the data more. I am on a Time of Day meter.
Title: Re: solar panel installation
Post by: RecoveringCarClown on October 14, 2015, 01:38:44 PM
So jealous Sol!  My power company will only give you credit for any excess power, they won't buy it.  Therefore I have not been able to make the numbers work, no matter how bad I want to do solar. I have the perfect roof for it too. :(
Title: Re: solar panel installation
Post by: zephyr911 on October 14, 2015, 01:59:17 PM
I'm not making individual stock investments anymore but one of my current holds is a financier that funds solar, wind, and efficiency projects. They consistently report that the highest ROI is on efficiency.

Like Mr. Miyagi said: "best block, no be there." Likewise, using less energy is almost always easier and more cost-effective than making more. Of course, I support both. But from an MMM perspective you will absolutely get the most bang for your buck on reducing consumption.
Title: Re: solar panel installation
Post by: Faraday on October 14, 2015, 03:59:58 PM
...
The summary is that we're installing twenty eight 270 watt panels on our south-facing roof, at a cost of $32,400 up front, to replace an estimated 75% of our home energy usage.  This system should more than pay for itself before 2020, after which we will essentially be getting free energy.

Hey Sol - any update to tell on your Solar Panel Adventure? I'm planning an installation before the credits run out. Thanks a ton for posting this thread!
Title: Re: solar panel installation
Post by: sol on October 14, 2015, 08:17:22 PM
Hey Sol - any update to tell on your Solar Panel Adventure? I'm planning an installation before the credits run out. Thanks a ton for posting this thread!

I posted a year end summary (http://forum.mrmoneymustache.com/welcome-to-the-forum/solar-panel-installation/msg782855/#msg782855) about a month ago that detailed our final numbers.  It turns out our panels produce significantly more than 100% of our annual power use, and we recently we received and deposited our first state incentive rebate check.  Cold hard cash in the bank.
Title: Re: solar panel installation
Post by: Faraday on October 14, 2015, 09:40:14 PM
I'll try copy and paste to see how this chart works.

Yeah that didn't work. I'll try this

b4u2, you've got something crazy going on there. Look at your "one year later" kwh usage compared to the same time a year earlier. You've nearly DOUBLED your KWH usage EVERY MONTH. Some comments I'll throw your way:

1) You're looking at tens or even low-hundreds of KWH difference year-to-year. That's not going to simply be wall-warts or light bulbs, that's something BIG that sucks a lot of power, or a major appliance that's malfunctioning. If your increase in KWH were somehow turned into 100% heat, you'd be burning down your house.

2) Do you have an electric water heater? How long since you've drained it, had the elements changed out and the anode rod replaced? I'd have a plumber come check it out if you have an electric water heater that's never been serviced/maintained.

3) If you have a heat pump, get one of the "seasonal checkups". If the unit's 10 years old or more, you may have a refrigerant leak from the A-coil. If it's a heat pump, ask the technician who checks it out to see what the "defrost timer" is set to. It should be 30 minutes or more. If it's less than 30 minutes, the defrost cycle may be running far too often and wasting power.

4) Are you on well water? If so, you could have a water leak somewhere and your well pump keeps running. This is a very important one to me - I go around the house and make sure none of the toilets are stuck "flushing" every day before I go to work.

5) You could have a refrigerator that's gone bad, that's possible. It could be cycling back and forth into and out of defrost cycle.

6) If you have been considering a NEST thermostat, get one. They are great.

Those are the quick thoughts I have off the top of my head on things that could be eating large amounts of energy.
Title: Re: solar panel installation
Post by: nawhite on October 15, 2015, 08:50:01 AM
I realized I never posted about the numbers on the system I had installed in April. Let me start with we didn't do it for the financial payback, we did it because we wanted to (we're a little crunchy but not too bad) and having panels makes our house MUCH more desirable in our market when we decide to sell in a year or two. We expect the sale price to more than cover the value of the panels plus help our house sell faster.

3.125KW grid-tie roof-mounted solar from SunRun.

Total cost: $12,175 - $500 gift card for taking the "put your deposit down today" incentive - $350 gift card for a referral = $11,325
Federal Rebate: 30% off of full price = $3652.50

Out of pocket cost: $7672.50 ($2.45 / Watt installed and warrantied)

We put $1000 down, got an interest free loan for the federal rebate portion that lasts until we file our taxes and the remaining $7500 ish is on a 2.99% loan.

We are in Denver, CO and get Net Metering (bank solar credits in summer to pay for usage in winter) + a check every month for $0.03/KWh produced. Electricity from the grid costs $0.11/KWh but then you can pay an additional $0.03 per KWh to get your power from wind which we were doing so our cost was really $0.14/KWh.

On average we were using 350 KWh / month of electricity (~$49) plus a $6/month connection charge for an average bill around $55/month.

Net Metering allows us to effectively generate 100% of our consumption and the $0.03 production incentive is usually around $8-10 per month or a little more than the connection charge so we are net positive on our electric bill. We replaced the electric bill with a fixed loan payment of around $62/month ($7672 @ 2.99%for 12 years). So we end up paying about $3-5 more than our current bill for 12 years but, after 12 years we don't have to pay for electricity again, and as electricity rates go up, our payment is fixed. (And in our housing market, "solar panels included" is worth more on the sale price than the panels themselves).

The other way of looking at the cost is we earn $49+$9 = $58/month and paid $7672 = 11 year payback = 9.1% return -2.99% interest on the loan = 6.1% return. It's not great, but we're ok with that. Its right around the long term post inflation CAGR of the stock market and way less volatile.

If anyone is thinking about solar, SunRun worked pretty well for us and they have an amazing referral program (value varies but it has been as high as I get $500 you get $500 if you use them as your installer). Let me know if you're interested in a referral.
Title: Re: solar panel installation
Post by: nereo on October 15, 2015, 09:04:02 AM
nice summary nawhite.  Thanks for sharing.
Title: Re: solar panel installation
Post by: zephyr911 on October 15, 2015, 09:36:26 AM
6) If you have been considering a NEST thermostat, get one. They are great.
There's a whole ongoing thread about those, I think in the real estate section. TBH, after seeing one in operation at one of my rentals for a year-plus, I think most of what it does can be achieved almost as well through behavior modification. IOW, the ROI is real but I believe it is much lower for Mustachians who are already using a simple programmable 'stat and actively building their own heat/cold tolerance through daily exposure and temp adjustments. NEST earns best for unenlightened laymen who use HVAC 365 days a year at exactly the same temperature (or, horror of horrors, inverted temps, 60s in summer and 70+ in winter).

I don't say this to denigrate the value or importance of their product in any fashion, and I think it's awesome that they do what they do. But there are many roads to optimization.

Caveats: obviously behavior can't stand in for an occupancy sensor or WiFi access.

(tl;dr: mindfulness does almost as well)
Title: Re: solar panel installation
Post by: nawhite on October 15, 2015, 10:55:52 AM
6) If you have been considering a NEST thermostat, get one. They are great.
There's a whole ongoing thread about those, I think in the real estate section. TBH, after seeing one in operation at one of my rentals for a year-plus, I think most of what it does can be achieved almost as well through behavior modification. IOW, the ROI is real but I believe it is much lower for Mustachians who are already using a simple programmable 'stat and actively building their own heat/cold tolerance through daily exposure and temp adjustments. NEST earns best for unenlightened laymen who use HVAC 365 days a year at exactly the same temperature (or, horror of horrors, inverted temps, 60s in summer and 70+ in winter).

I don't say this to denigrate the value or importance of their product in any fashion, and I think it's awesome that they do what they do. But there are many roads to optimization.

Caveats: obviously behavior can't stand in for an occupancy sensor or WiFi access.

(tl;dr: mindfulness does almost as well)

This was definitely my experience too. The batteries died in my thermostat in early September and I haven't replaced them yet so I haven't had any heating or cooling from my HVAC system at all. Instead I've just been doing:

Oh it's going to get hot today, lets open the doors and windows right when I get up or overnight to get the house cold in the morning and then close them all up and shut the blinds/curtains before the sun gets strong. Or
Oh it's going to be cold today, better open up all of the blinds and curtains immediately when I wake up.

My friends have a Nest and it keeps their house very comfortable, but when I'm already only running the HVAC for less than an hour a day most days I can't see it really saving me that much money? Take that $200 for a nest and buy some bags of insulation for your attic, you'll save more money.
Title: Re: solar panel installation
Post by: b4u2 on October 28, 2015, 08:53:14 AM
I think I "may" have found the issue. A simple explanation is that the dryer is not shutting off. I only noticed this the other day when my wife went to unload dryer that I had started and she said it was still running. I checked the time and realized I started that dryer nearly 2 hours ago! I went down and the meter still said damp. I stopped the dryer and checked, all the clothes were dry. My step son typically does his laundry late at night and no one notices if the dryer continues to run because we are all asleep. It does appear to eventually turn off but there must be a sensor that is bad? I am going to check into this more.

I do own a kill-a-watt and need to learn how to use it and start testing other appliances and see if they are drawing more than they should. Most of the stuff in the house is getting old. I bought the house new 13 years ago so I am sure certain appliances are going to start going bad now. Of course I don't really have money to replace them but neither can I allow them to eat up electric.

I'll try copy and paste to see how this chart works.

Yeah that didn't work. I'll try this

b4u2, you've got something crazy going on there. Look at your "one year later" kwh usage compared to the same time a year earlier. You've nearly DOUBLED your KWH usage EVERY MONTH. Some comments I'll throw your way:

1) You're looking at tens or even low-hundreds of KWH difference year-to-year. That's not going to simply be wall-warts or light bulbs, that's something BIG that sucks a lot of power, or a major appliance that's malfunctioning. If your increase in KWH were somehow turned into 100% heat, you'd be burning down your house.

2) Do you have an electric water heater? How long since you've drained it, had the elements changed out and the anode rod replaced? I'd have a plumber come check it out if you have an electric water heater that's never been serviced/maintained.

3) If you have a heat pump, get one of the "seasonal checkups". If the unit's 10 years old or more, you may have a refrigerant leak from the A-coil. If it's a heat pump, ask the technician who checks it out to see what the "defrost timer" is set to. It should be 30 minutes or more. If it's less than 30 minutes, the defrost cycle may be running far too often and wasting power.

4) Are you on well water? If so, you could have a water leak somewhere and your well pump keeps running. This is a very important one to me - I go around the house and make sure none of the toilets are stuck "flushing" every day before I go to work.

5) You could have a refrigerator that's gone bad, that's possible. It could be cycling back and forth into and out of defrost cycle.

6) If you have been considering a NEST thermostat, get one. They are great.

Those are the quick thoughts I have off the top of my head on things that could be eating large amounts of energy.
Title: Re: solar panel installation
Post by: zephyr911 on October 28, 2015, 11:11:56 AM
I think I "may" have found the issue. A simple explanation is that the dryer is not shutting off. I only noticed this the other day when my wife went to unload dryer that I had started and she said it was still running. I checked the time and realized I started that dryer nearly 2 hours ago! I went down and the meter still said damp. I stopped the dryer and checked, all the clothes were dry. My step son typically does his laundry late at night and no one notices if the dryer continues to run because we are all asleep. It does appear to eventually turn off but there must be a sensor that is bad? I am going to check into this more.
Ouch! Yeah, dryers are a huge energy suck, and one that's running when it should turn off could easily cost you tons of money.
I have a pretty good/cheap appliance guy on call so I'd just point him at it and call it good, but if you have time to troubleshoot... it might be a very easy repair. Concur that sensor is a good guess, though a control board could be the issue too.

As for the other appliances... you can always unplug when not in use to reduce idle current draw.
Title: Re: solar panel installation
Post by: Faraday on October 28, 2015, 12:36:58 PM
I think I "may" have found the issue. A simple explanation is that the dryer is not shutting off. I only noticed this the other day when my wife went to unload dryer that I had started and she said it was still running. I checked the time and realized I started that dryer nearly 2 hours ago! I went down and the meter still said damp. I stopped the dryer and checked, all the clothes were dry. My step son typically does his laundry late at night and no one notices if the dryer continues to run because we are all asleep. It does appear to eventually turn off but there must be a sensor that is bad? I am going to check into this more.
Ouch! Yeah, dryers are a huge energy suck, and one that's running when it should turn off could easily cost you tons of money.
I have a pretty good/cheap appliance guy on call so I'd just point him at it and call it good, but if you have time to troubleshoot... it might be a very easy repair. Concur that sensor is a good guess, though a control board could be the issue too.

As for the other appliances... you can always unplug when not in use to reduce idle current draw.

I wonder if lint could be collecting on the sensor and stopping it from working.
Title: Re: solar panel installation
Post by: Jeddy on October 28, 2015, 01:14:53 PM
I think I "may" have found the issue. A simple explanation is that the dryer is not shutting off. I only noticed this the other day when my wife went to unload dryer that I had started and she said it was still running. I checked the time and realized I started that dryer nearly 2 hours ago! I went down and the meter still said damp. I stopped the dryer and checked, all the clothes were dry. My step son typically does his laundry late at night and no one notices if the dryer continues to run because we are all asleep. It does appear to eventually turn off but there must be a sensor that is bad? I am going to check into this more.

http://www.repairclinic.com/RepairHelp/How-To-Fix-A-Dryer/7---/Dryer-won-t-stop?r=%2fShop-For-Parts%2fa8%2fDryer-Parts

RepairClinic.com - dryer issues - dryer won't stop. Check out what they advise (and plug in your model number for the parts you need for your specific dryer) - dryers are simple to fix and the parts are relatively cheap (much cheaper than getting someone to come check it out or buying a new one). Youtube can show you how to replace anything in a dryer (and any other appliance) if you aren't comfortable with it. 
Title: Re: solar panel installation
Post by: b4u2 on October 28, 2015, 03:34:52 PM
The dryer outlet on the outside of the house was clogged. Hopefully that fixes the problem. I normally clean it but overlooked it this year somehow.

How do I find the KWH cost for Cedar Rapids, IA with Alliant Energy? I am also on the time of day meter. I plugged the Kill-A-Watt into the fridge and want to see what it is costing me. I figured once I get the hang of it I'll start testing other appliances as well.
Title: Re: solar panel installation
Post by: nereo on October 28, 2015, 07:35:54 PM
How do I find the KWH cost for Cedar Rapids, IA with Alliant Energy?

It should be on your last electricity bill.  A quick "googling" suggests the average is 12.9/kw*h.  However, check yours... often you'll have different rates based on either the time of day or your rate will go up after you consume a certain amount of power per day.
Title: Re: solar panel installation
Post by: Faraday on October 28, 2015, 08:31:29 PM
How do I find the KWH cost for Cedar Rapids, IA with Alliant Energy?

It should be on your last electricity bill.  A quick "googling" suggests the average is 12.9/kw*h.  However, check yours... often you'll have different rates based on either the time of day or your rate will go up after you consume a certain amount of power per day.

Remember to add in any fees and cost recovery line items on  your bill. The true KWH cost is what you pay, not some number the power company fabricates to make it look cheaper.

Example: My local Electric Membership Co-Op claims they charge me 11 cents/KWH. But after all their line items, I pay 14 cents/KWH.

That's the real, actual amount I've always paid. It's not like I get to call them up and refuse to pay the other line items.
Title: Re: solar panel installation
Post by: nereo on October 28, 2015, 09:09:38 PM
How do I find the KWH cost for Cedar Rapids, IA with Alliant Energy?

It should be on your last electricity bill.  A quick "googling" suggests the average is 12.9/kw*h.  However, check yours... often you'll have different rates based on either the time of day or your rate will go up after you consume a certain amount of power per day.

Remember to add in any fees and cost recovery line items on  your bill. The true KWH cost is what you pay, not some number the power company fabricates to make it look cheaper.

Example: My local Electric Membership Co-Op claims they charge me 11 cents/KWH. But after all their line items, I pay 14 cents/KWH.

That's the real, actual amount I've always paid. It's not like I get to call them up and refuse to pay the other line items.
No....  When you are looking at the how much energy a typical appliance is using (and what that is costing) you ignore any fees and line items.  Those items don't go away if you add or subtract energy usage.
So if you learn that your amplifier draws 100 watts when left in standby and you pay 10/kw, your amp is costing you 1 per hour. 

Knowing what those line items are is always a good thing.  Ironically, your total cost per KW will go UP as your energy usage goes down for that very reason.
Title: Re: solar panel installation
Post by: Faraday on October 28, 2015, 10:33:09 PM
How do I find the KWH cost for Cedar Rapids, IA with Alliant Energy?

It should be on your last electricity bill.  A quick "googling" suggests the average is 12.9/kw*h.  However, check yours... often you'll have different rates based on either the time of day or your rate will go up after you consume a certain amount of power per day.

Remember to add in any fees and cost recovery line items on  your bill. The true KWH cost is what you pay, not some number the power company fabricates to make it look cheaper.

Example: My local Electric Membership Co-Op claims they charge me 11 cents/KWH. But after all their line items, I pay 14 cents/KWH.

That's the real, actual amount I've always paid. It's not like I get to call them up and refuse to pay the other line items.
No....  When you are looking at the how much energy a typical appliance is using (and what that is costing) you ignore any fees and line items.  Those items don't go away if you add or subtract energy usage.
So if you learn that your amplifier draws 100 watts when left in standby and you pay 10/kw, your amp is costing you 1 per hour. 

Knowing what those line items are is always a good thing.  Ironically, your total cost per KW will go UP as your energy usage goes down for that very reason.

You still pay the final bill, one way or another. Your point seems to be a meaningless shill for The Man.
Title: Re: solar panel installation
Post by: sol on October 28, 2015, 10:48:44 PM
You still pay the final bill, one way or another. Your point seems to be a meaningless shill for The Man.

I disagree, and this is my thread so I get to do that.

Those flat fees are unrelated to how much power you use.  You pay them if you use zero, so they're more like a tax due unto Caesar.  Scaling your power consumption in either direction will not avoid them.  They're a fixed cost.

But your per kWh cost is scalable.  If you used zero, you would pay zero.  Separating out the per kWh cost from the fixed cost is the only way this accounting makes any sense.  Including your fixed costs in your total per kWh charges is like including your income tax in your sales tax.  Only one of those things depends on how much you buy, so only one of them needs to be considered when making the cost comparisons vs not buying.

Unless you're going totally off grid and avoiding those fixed fees all together.  In that case I'd give your math a pass, but for ordinary folks who are maintaining a grid connection in addition to utilizing solar panels to reduce their consumption, those residual fees are not offset by your solar panels in any way so including them in your solar payback period doesn't make any sense.
Title: Re: solar panel installation
Post by: b4u2 on October 29, 2015, 07:05:03 AM
What I found disturbing was when I called customer service they couldn't even give me an answer. Here is a summary for the last two months.
It is amazing how the bill amount varied between the two months but they can't break it down for me. The main onpeak and offpeak charges don't even come with a cost break down just a total?
I found a rate sheet but I haven't been able to do the math yet to make any number match what is actually on the bill. I have the time of day meter.
Title: Re: solar panel installation
Post by: Posthumane on October 29, 2015, 08:11:57 AM
Sol, that's true if the fees that are being discussed are billed as fixed monthly fees. However, my power company advertises a certain electricity rate per kWh (say 10c), but they have additional charges which are also billed as per kWh items. My electricity bill has a breakdown that lists something like this:

Monthly grid fee - $10
Energy Charge (100 kWh @ 0.100/kWh) - $10
Going Green fee (100 kWh @ 0.025/kWh) - $2.50
Service Charge (100 kWh @ 0.014/kWh) - $1.40
etc...
So the "fees" on my bill are somewhat scalable with usage, just not all of them, and my actual usage cost is higher than the advertised electricity rate.
Title: Re: solar panel installation
Post by: RetiredAt63 on October 29, 2015, 09:08:03 AM
Ontario Hydro also splits costs, but the extra charges have a small fixed amount and after that they are directly related to consumption.  Extra charges (delivery, Regulatory charges and debt repayment) are always more than the actual use charges.  I am paying for debt Hydro-One incurred while I lived in Quebec - so fun.
Title: Re: solar panel installation
Post by: zephyr911 on October 29, 2015, 09:34:19 AM
The dryer outlet on the outside of the house was clogged. Hopefully that fixes the problem.
Yeah, that could easily have been reducing the moisture egress and telling the sensor the load was wet.
Title: Re: solar panel installation
Post by: Faraday on October 29, 2015, 10:06:34 AM
You still pay the final bill, one way or another. Your point seems to be a meaningless shill for The Man.

I disagree, and this is my thread so I get to do that.

Those flat fees are unrelated to how much power you use.  You pay them if you use zero, so they're more like a tax due unto Caesar.  Scaling your power consumption in either direction will not avoid them.  They're a fixed cost.

Sol, you are  right and I agree completely with what you have said: those line items don't go away unless you disconnect from the grid and scaling your power consumption in either direction will not avoid them.  What you said is consistent with what I learned working for Carolina Power & Light (Now Duke Energy) in their distribution division for over six years. 

I DO have some questions I wanted to get to, that I wanted to pose to you and others who have actual panels on the roof right now making power.

Can we drop it and move on to more important issues, please? I'm glad to sacrifice my comment to get to the more important issues that will keep this thread useful. I have much bigger fish to fry than arguing about what people mistakenly assume I said. I can delete my original comment, or replace it with a line item listing of my own fees. I just want to get to the important stuffs.
Title: Re: solar panel installation
Post by: sol on October 29, 2015, 10:32:34 AM
No worries, important stuff always displaces old conversations here anyway.  Ask away!
Title: Re: solar panel installation
Post by: Faraday on October 29, 2015, 11:44:43 AM
No worries, important stuff always displaces old conversations here anyway.  Ask away!

I'll review the thread to see if I'm asking something that's already been asked, but I'll go ahead with these questions:

1) I think your panels are on your roof, right? What kind of roof structure do you have - is it rafters or trusses?
2) Were there any special challenges your installers had with your roof?

(My roof is built on top of trusses made with 2x4 lumber, so that dramatically increases the precision required to hit the center of the 2x4. That worries the hell out of me, enough so that I'm actually considering first going with a standing seam metal roof so I could use the clips and not have to worry where the truss edges fall on the roof deck...)

(and this is the one I think has been answered, but I can't recall for sure...)
3) You have a net-meter, right? And did it have to be installed, by the power company, BEFORE your array came online? Do you have to pay a monthly base surcharge for that meter? My power provider requires a $3/month charge for the dual-reading net meter.

Side note: I'm VERY close to adding three or four panels with microinverters, grid-tied. I plan to run about four or five 275 watt panels that way for awhile and gather real-world data on how much power I can generate at my site (and how many trees I REALLY need to cut). Then from there, I plan to build out the rest of the system and eventually add battery power. (Probably using AC coupling, to preserve the investment in the microinverters.)

I don't know that I'll ever go completely off-grid, but I am going to push myself as close to that line as I can.
Title: Re: solar panel installation
Post by: sol on October 29, 2015, 12:12:59 PM
1) I think your panels are on your roof, right? What kind of roof structure do you have - is it rafters or trusses?
2) Were there any special challenges your installers had with your roof?


I paid to have my panels installed professionally, so I'm afraid I can't speak to the difficulties involved.  It was a two day install job for 28 panels, with a two or three man crew.  One day to put up the racking and run the wires while the electrician installed the inverters in the garage, and a second to lift all the panels on to the roof and connect them.

The racking system was installed over the shingles.  Presumably it is anchored to studs but I haven't looked, sorry.

The panels stand about 4 inches off of the roof.  The only change made to the roof was to shorten the sewer vent stacks so they would still be open, under the panels.  Code here requires 14 inches of vent pipe above roof level to prevent clogging by very occasional snowfall, but that's not an issue under panels so we just shortened them.  If the panels ever come off, I'll have to lengthen those pipes again.  The panels were installed right over the top of my attic vents.

Quote
3) You have a net-meter, right? And did it have to be installed, by the power company, BEFORE your array came online? Do you have to pay a monthly base surcharge for that meter? My power provider requires a $3/month charge for the dual-reading net meter.

Yes, we have a net meter.  Our regular meter measures net power consumption, so it runs backwards during the day.  We  had to have a second meter installed that measures just the power coming down from the roof and feeding into the net meter.  That one only counts up to measure power generated, and that's the one the power company reads once per year to determine my production incentive payment ($4969 last year).

Yes, we had to have that meter installed and certified before we could start accruing production incentives, but the system was running for like three days before they got here to certify it.  We just didn't earn any production incentives for those first three days, though we did effectively earn the retail rate for power by reducing our net meter total for the billing period.

We do not pay a monthly fee for the net meter specifically, but we do pay other monthly fees and I think it was like $200 up front (paid by my installer and figured into his cost to me) for the city to install the second meter.

Like every power customer here, we pay a $10/month grid connection fee, recently increased from $5/month when they lowered the retail cost of power a little bit.  I suspect too many people like me were taking advantage of the incentive program, so the utility lowered per kWh rates and raised the fixed fee, which effectively penalized solar panel owners twice.  I now pay more in fixed fees and get paid less for the power I provide to the grid.  For most normal (non solar-producing) customers, this change was a slight to moderate cost savings, depending on their usage.
Title: Re: solar panel installation
Post by: Faraday on October 29, 2015, 12:24:40 PM
...
Like every power customer here, we pay a $10/month grid connection fee, recently increased from $5/month when they lowered the retail cost of power a little bit.  I suspect too many people like me were taking advantage of the incentive program, so the utility lowered per kWh rates and raised the fixed fee, which effectively penalized solar panel owners twice.  I now pay more in fixed fees and get paid less for the power I provide to the grid.  For most normal (non solar-producing) customers, this change was a slight to moderate cost savings, depending on their usage.

Yeah, THAT is precisely the thing about the fees that has me bent out of shape. I am served by an Electric Membership Co-Op and their industry consortium, "Touchstone Energy", serves as the main lobbying arm for the industry. They seem to be able to get fees like that past the State Utilities Commission without so much as a whimper and I honestly don't understand.

OK, so NC doesn't have any production incentives like you enjoy. I can live with that. But damn, the power providers here  erected financial barriers to solar energy production. It's a shocking and aggressive move by the grid power providers....

Give me a little more time - I have more questions but need to get back to work. :-/
Title: Re: solar panel installation
Post by: nawhite on October 29, 2015, 12:57:26 PM
1) I think your panels are on your roof, right? What kind of roof structure do you have - is it rafters or trusses?
2) Were there any special challenges your installers had with your roof?

3) You have a net-meter, right? And did it have to be installed, by the power company, BEFORE your array came online? Do you have to pay a monthly base surcharge for that meter? My power provider requires a $3/month charge for the dual-reading net meter.

1) I have rafters. The panels just screw into the shingles and the plywood under the shingles, no concern with connecting to a rafter or truss.
2) No problems that I'm aware of. My installation crew had about 6 people and did 12 panels in 4 hours. Got there first thing in the morning and were gone by lunch and I'm sure they did another install after lunch.
3) When the system was installed it was all ready except for a they had installed a second meter box but no meter. I had to wait a couple weeks for the power company to come out and put the second meter in the box and replace the old meter with a new "net" meter. This new meter measured power generated by the panels and the net meter measured net power usage by my home (usage - generated). I do not pay any additional fee for that second meter currently.
Title: Re: solar panel installation
Post by: Faraday on October 29, 2015, 03:02:47 PM
1) I think your panels are on your roof, right? What kind of roof structure do you have - is it rafters or trusses?
2) Were there any special challenges your installers had with your roof?

3) You have a net-meter, right? And did it have to be installed, by the power company, BEFORE your array came online? Do you have to pay a monthly base surcharge for that meter? My power provider requires a $3/month charge for the dual-reading net meter.

1) I have rafters. The panels just screw into the shingles and the plywood under the shingles, no concern with connecting to a rafter or truss.
2) No problems that I'm aware of. My installation crew had about 6 people and did 12 panels in 4 hours. Got there first thing in the morning and were gone by lunch and I'm sure they did another install after lunch.
3) When the system was installed it was all ready except for a they had installed a second meter box but no meter. I had to wait a couple weeks for the power company to come out and put the second meter in the box and replace the old meter with a new "net" meter. This new meter measured power generated by the panels and the net meter measured net power usage by my home (usage - generated). I do not pay any additional fee for that second meter currently.

Thank you nawhite, that's super info, much appreciated. It's impressive as hell to me that 6 people got 12 panels installed in 4 hours. That sounds like they were very experienced and knew their roles well.

I'm guessing you have microinverters on each solar panel, so that all they had to do was pull an AC conduit, add a disconnect switch and route the line to an empty breaker in your external breaker box?
Title: Re: solar panel installation
Post by: nawhite on November 01, 2015, 05:04:06 PM
I'm guessing you have microinverters on each solar panel, so that all they had to do was pull an AC conduit, add a disconnect switch and route the line to an empty breaker in your external breaker box?

Not micro inverters, just one big one. Made it so they just had to plug them in series and one conduit for the return. It also helped that they could install them all on one big mounting rail all in a line. Made it simple.
Title: Re: solar panel installation
Post by: Faraday on November 01, 2015, 09:22:46 PM
I'm guessing you have microinverters on each solar panel, so that all they had to do was pull an AC conduit, add a disconnect switch and route the line to an empty breaker in your external breaker box?

Not micro inverters, just one big one. Made it so they just had to plug them in series and one conduit for the return. It also helped that they could install them all on one big mounting rail all in a line. Made it simple.

Wait, wait: so you had the rails pre-installed on the roof for the solar installers?
Title: Re: solar panel installation
Post by: nawhite on November 02, 2015, 12:30:19 PM
I'm guessing you have microinverters on each solar panel, so that all they had to do was pull an AC conduit, add a disconnect switch and route the line to an empty breaker in your external breaker box?

Not micro inverters, just one big one. Made it so they just had to plug them in series and one conduit for the return. It also helped that they could install them all on one big mounting rail all in a line. Made it simple.

Wait, wait: so you had the rails pre-installed on the roof for the solar installers?

No, sorry I don't have pictures. But take a look at Sol's pictures from near the start of the thread http://forum.mrmoneymustache.com/welcome-to-the-forum/solar-panel-installation/msg354102/#msg354102. Sol has 4 rows of 7 panels each. Mine has 1 row of 12 panels. And mine are rotated 90 degrees compared to Sol's so there are just two rails on the roof instead of 14. Made the install really easy for the installers.
Title: Re: solar panel installation
Post by: Faraday on November 02, 2015, 12:51:03 PM
No, sorry I don't have pictures. But take a look at Sol's pictures from near the start of the thread http://forum.mrmoneymustache.com/welcome-to-the-forum/solar-panel-installation/msg354102/#msg354102. Sol has 4 rows of 7 panels each. Mine has 1 row of 12 panels. And mine are rotated 90 degrees compared to Sol's so there are just two rails on the roof instead of 14. Made the install really easy for the installers.

Thank you nawhite. If I understand you correctly, your rails are oriented the way I expect to do them at my place, horizontally. The panels will be oriented vertically.
Title: Re: solar panel installation
Post by: sol on March 09, 2016, 08:24:45 PM
After almost 18 months of operation, our solar panels appear to be generating a net surplus of ~5200 kWh per year, measured as a running annual average.  That's net surplus on top of what our household actually uses (about another 5000 kWh/year).

We just bought a Nissan Leaf (http://forum.mrmoneymustache.com/welcome-to-the-forum/buying-a-nissan-leaf/) all-electric car.  If it drives 1000 miles/month at 3.9 kWh/mile, it will use 256 kWh of electricity at a cost of 7.41 cents per kWh.  That works out to 1.9 cents per mile, or $19/mo.  In a year of driving, the Leaf should use about 3000 kWh and cost us $230 in electricity.

So if our solar panels are already generating 5200 kWh of surplus energy, and the car is going to consume about 3000 kWh of that, then on an annual basis our panels should still generate more power than our house and car together will use.  We're approaching net zero.

Before the Leaf, our panels were generating about $400 in free power that we used in our home, and then $400/year in surplus (~10,000 kWh at 8.75 cents/kWh).
After the Leaf, our panels should generate the same $370 in free power that we use at home, $230 in power for the Leaf, and then about $160/year in surplus energy (2128 kWh at 7.41 cents/kWh), in part because our power rates went down.

Separate from these cost savings are the $5,000/year production incentive, which we get for generating at least 9260 kWh gross power, before household usage, at 54 cents/kWh. 

Also separate is the cost of gasoline we're not burning by driving the Leaf.  At $2/gallon the SUV costs us 11.7 cents/mile in gas (as compared to 1.9 cents/mile for the Leaf).  So driving 1000 miles/mo in the Leaf instead of the SUV would save us $98/mo in net fuel cost after accounting for electricity costs.  So that's ~$1400 in avoided gasoline costs and $230 in new power costs, for a net savings of $1170/year.  So from a financial perspective, our electricity is much more efficiently spent driving our car (if it displaces gasoline) than being sold back to the grid.

If I've done the math right, our household budget should be improved by $5k+$1170+$370+$160 = $7000 per year by having solar panels and an electric car.  That's $7k more I can put into the stock market.  Our total out of pocket costs for these items was about $30,000 (32k solar panels - 30% tax rebate +$7700 car), so one convoluted way to look at this math is that we're "earning" $7000 on $30k, or 23.3% guaranteed return per year.  That only lasts until 2020, at which point the production incentives expire, and our return drops to a more meager $2000/$30k or 6.66% per year.  Good for the environment AND my bottom line!

That math is more than a little bogus because it's figured on initial purchase price, not compound growth, because those profits are not re-invested into more income-producing assets like they would be if they were stock earnings.  I'm not complaining.
Title: Re: solar panel installation
Post by: nereo on March 10, 2016, 05:02:16 AM
awesome update Sol.  I was actually wondering a few weeks ago how your power generation might have changed during this latest el nino and the rain it has brought.  Do you know how much power your panels collected in Jan/Feb 2015 vs 2014?

Quote
Also separate is the cost of gasoline we're not burning by driving the Leaf.  At $2/gallon the SUV costs us 11.7 cents/mile in gas (as compared to 1.9 cents/mile for the Leaf).  So driving 1000 miles/mo in the Leaf instead of the SUV would save us $98/mo in net fuel cost after accounting for electricity costs.  So that's ~$1400 in avoided gasoline costs and $230 in new power costs, for a net savings of $1170/year. So from a financial perspective, our electricity is much more efficiently spent driving our car (if it displaces gasoline) than being sold back to the grid.

sounds like you've found a good way to diversify yourself from being dependent on selling power back to the utility.  There's on guarantee that your utility will continue to buy back excess power in the future, right?
Now I'm curious about your experiences with the Leaf.  I'm guessing you also looked at the Volt and decided for the Leaf for some reason. 

An EV isn't in the cards for us just yet due to our onstreet parking situation (no way to plug it in as of right now). 
Title: Re: solar panel installation
Post by: brooklynguy on March 10, 2016, 07:16:06 AM
Thanks for the update.  You keep us energy-usage voyeurs happy.

That math is more than a little bogus because it's figured on initial purchase price, not compound growth, because those profits are not re-invested into more income-producing assets like they would be if they were stock earnings.

I think the math is actually bogus for a different reason.  You can reinvest your returns (the electricity/gasoline cost savings) however you please, including in productive assets like stocks.  But that math ignores the fact that you will never recoup any of your initial purchase price (assuming the solar panel system and LEAF will both eventually depreciate to zero).  But even factoring that in, it looks like you are getting a pretty solid return on your investment.
Title: Re: solar panel installation
Post by: MasterStache on March 10, 2016, 08:56:03 AM
Great update, wish I would have found this thread sooner. I'll read through it more in depth when I have some time. I understand you paid a company to install the panels? I wonder what sort of cost savings you could have created by installing yourself.

I installed 28 panels (I briefly spoke about this on your Leaf thread) in 2012 for total system cost of just under 15K, minus federal rebates. My panels were only 205 watts/per panel also. And I actually purchased them in 2011. I received a couple quotes of around 30K for a comparable system, so I figure I saved around half of the total cost by simply doing it myself. We sold the house in December 2014 and the solar array and subsequent energy savings were a huge selling feature. 
Title: Re: solar panel installation
Post by: Axecleaver on March 10, 2016, 10:46:20 AM
Great update, I'm jealous of your production incentive.

The way I'd look at the return is to consider the ROI. You've put in capital expenditures of ~$30k net after tax rebate. You generated $6275 in return last year: 400 in free power, 875 in excess power sold back to the grid, 5k in production incentives.  In future years you'll generate 7k a year. This probably accelerates as energy prices increase. So on a balance sheet:

Year Cost/      ROI
        Benefit
0     -32000   -32000 capex solar panels
0        9600    -22400 30% tax rebate 
1        6275    -16125 first year returns on power
2       -7700    -23825 capex leaf
2        7000    -16825  Year 2 returns on power
3        7500      -9325  Year 3 returns on power
4        8000      -1325  Year 4 returns on power
4        8500      7175   Year 5 returns on power; Break even point reached

So, if you hadn't bought the car, you would have achieved break even on your solar panels in year 3. The car capex slowed down your break even, but only by another year. The real value here is achieving energy independence and insulation from future energy shocks. That's a valuable risk mitigation achievement that shouldn't be overlooked. And, free solar panels after 3-4 years. Pretty awesome.
Title: Re: solar panel installation
Post by: Prairie Stash on March 10, 2016, 11:27:22 AM
Great update, I'm jealous of your production incentive.

The way I'd look at the return is to consider the ROI. You've put in capital expenditures of ~$30k net after tax rebate. You generated $6275 in return last year: 400 in free power, 875 in excess power sold back to the grid, 5k in production incentives.  In future years you'll generate 7k a year. This probably accelerates as energy prices increase. So on a balance sheet:

Year Cost/      ROI
        Benefit
0     -32000   -32000 capex solar panels
0        9600    -22400 30% tax rebate 
1        6275    -16125 first year returns on power
2       -7700    -23825 capex leaf
2        7000    -16825  Year 2 returns on power
3        7500      -9325  Year 3 returns on power
4        8000      -1325  Year 4 returns on power
4        8500      7175   Year 5 returns on power; Break even point reached

So, if you hadn't bought the car, you would have achieved break even on your solar panels in year 3. The car capex slowed down your break even, but only by another year. The real value here is achieving energy independence and insulation from future energy shocks. That's a valuable risk mitigation achievement that shouldn't be overlooked. And, free solar panels after 3-4 years. Pretty awesome.
You forget the depreciated value of the car. The balance sheet should show the cars value every year, it drastically improves the outcome.

I would show it as year 2-1$500 for the car, year 3 -$1200 etc. basically the cars depreciation (I don't really know the numbers, just guessing). He didn't lose $7700 all at once, he has the option to change his mind at any time and get some money back. 

Solar panels are harder to get money back from due to the removal/installation cost. When I looked at installing the installation was the same as the system, If I were to buy his used I couldn't offer much due to the labour costs for removal/install. That's why they aren't worth much after year 1, almost 100% depreciation unless sold with the house.
Title: Re: solar panel installation
Post by: ulrichw on March 10, 2016, 05:41:52 PM
I'm guessing with ~5000kWh of usage per year that your heat is probably natural gas.

The other thing you may want to look into (given probably temperate winters in your area) is installing heat pumps for heating (specifically ductless mini-splits, which are the most efficient). Depending on your heating load.

I'm considering doing exactly that (we just installed solar and also recently leased a VW E-Golf). In our case, I'm hoping to use the mini-splits as the main source of heating, while keeping the gas furnace for those times when we need a lot of heat quickly.
Title: Re: solar panel installation
Post by: sol on March 10, 2016, 09:02:50 PM
Do you know how much power your panels collected in Jan/Feb 2015 vs 2014?

Not exactly, no.  I know how much net surplus they generated above my household usage, but the only way to know the total PV generation is to manually read the direct power meter each month, or plug a laptop into my inverters.   Neither of which I have bothered to do.  It might be a fun weekend project at some point to download all of the inverter data, though.

Quote
There's on guarantee that your utility will continue to buy back excess power in the future, right?

No, and they've already started screwing with solar people by lowering the retail cost of electricity (thus lowering the rate they pay me for my surplus) and making up for it by increasing the monthly connection fee by 100%.   Most users saw no change in their bill.  Solar PV household saw their refund checks shrink by about 15% overnight.

Quote
Now I'm curious about your experiences with the Leaf.  I'm guessing you also looked at the Volt and decided for the Leaf for some reason. 

The Volt, like the Prius, still sends money to terrorists.  It still burns gasoline.  I wanted a pure EV with no tailpipe emissions at all, no blood money for ISIS, no cancer-causing fumes while refueling, lower operating and maintenance costs, no noise pollution, and 100% fueled by the solar panels on my roof.  Fortunately, my driving profile made a pure EV a good fit for my family.  I don't do long commutes, for reasons related to my hatred of traffic and waste.

If you're still interested in the Leaf, I wrote a whole post (http://forum.mrmoneymustache.com/welcome-to-the-forum/buying-a-nissan-leaf/) about it.  Hybrids are still gasoline cars, which are dirty and expensive and complicated machines, and then they ALSO have an EV system on top of that.  Pure EVs are simple, by comparison.

that math ignores the fact that you will never recoup any of your initial purchase price

Yes, and we discussed this point earlier in this very thread.  The solar panels have some residual value, but it's probably less than half of what I paid to have them installed.  It complicates the ROI calculation because you can depreciate them many different ways.

I understand you paid a company to install the panels? I wonder what sort of cost savings you could have created by installing yourself.

I paid for installation.  When I was shopping in 2014, residential solar panel installations were about 50% materials and 50% labor/design/permitting.  You need a licensed electrician to install the power meters and required safety devices.  And the material cost can vary widely, depending on where you're getting your panels and inverters from.  In my case, I paid a premium for the (locally manufactured) hardware in order to qualify for the (much higher) in-state production incentive of 54 cents/kWh produced on the roof.

I'm guessing with ~5000kWh of usage per year that your heat is probably natural gas.

The other thing you may want to look into (given probably temperate winters in your area) is installing heat pumps for heating (specifically ductless mini-splits, which are the most efficient).

Yes, our current furnace is natural gas (though the blower is of course electric).  It's also 18 years old and original to the house, so when it dies we'll probably install a traditional heat pump system in the same spot, since our house is already ducted.

Title: Re: solar panel installation
Post by: Mrs. PoP on March 11, 2016, 05:53:17 PM
Do you know how much power your panels collected in Jan/Feb 2015 vs 2014?

Not exactly, no.  I know how much net surplus they generated above my household usage, but the only way to know the total PV generation is to manually read the direct power meter each month, or plug a laptop into my inverters.   Neither of which I have bothered to do.  It might be a fun weekend project at some point to download all of the inverter data, though.

Do you know what brand of inverters you have, Sol?   Ours are Enphase and communicate the panel production to A small box that feeds that information to our Enphase account.  Then I just open my Enphase app and it tells me exactly how many kWh we produced each hour.  To figure out how much we use on a monthly basis I just have to subtract the net surplus we sent to the grid for that same period.  I've been keeping track pretty closely in our first year to make sure production/usage is where we expected it to be.

Not gonna lie though, I love checking the app on a sunny day and seeing my solar panels cranking out the kWh. 

Title: Re: solar panel installation
Post by: monarda on March 11, 2016, 07:01:20 PM
Do you know how much power your panels collected in Jan/Feb 2015 vs 2014?

Not exactly, no.  I know how much net surplus they generated above my household usage, but the only way to know the total PV generation is to manually read the direct power meter each month, or plug a laptop into my inverters.   Neither of which I have bothered to do.  It might be a fun weekend project at some point to download all of the inverter data, though.

Do you know what brand of inverters you have, Sol?   Ours are Enphase and communicate the panel production to A small box that feeds that information to our Enphase account.  Then I just open my Enphase app and it tells me exactly how many kWh we produced each hour.  To figure out how much we use on a monthly basis I just have to subtract the net surplus we sent to the grid for that same period.  I've been keeping track pretty closely in our first year to make sure production/usage is where we expected it to be.

Not gonna lie though, I love checking the app on a sunny day and seeing my solar panels cranking out the kWh. 



Mrs.PoP, it sounds like you have microinverters? That's what we have. The Enphase Enlighten is a nice app- we use it too.  But I'm not sure that it works with the regular inverters
Title: Re: solar panel installation
Post by: Mrs. PoP on March 12, 2016, 03:51:06 AM
Do you know how much power your panels collected in Jan/Feb 2015 vs 2014?

Not exactly, no.  I know how much net surplus they generated above my household usage, but the only way to know the total PV generation is to manually read the direct power meter each month, or plug a laptop into my inverters.   Neither of which I have bothered to do.  It might be a fun weekend project at some point to download all of the inverter data, though.

Do you know what brand of inverters you have, Sol?   Ours are Enphase and communicate the panel production to A small box that feeds that information to our Enphase account.  Then I just open my Enphase app and it tells me exactly how many kWh we produced each hour.  To figure out how much we use on a monthly basis I just have to subtract the net surplus we sent to the grid for that same period.  I've been keeping track pretty closely in our first year to make sure production/usage is where we expected it to be.

Not gonna lie though, I love checking the app on a sunny day and seeing my solar panels cranking out the kWh. 



Mrs.PoP, it sounds like you have microinverters? That's what we have. The Enphase Enlighten is a nice app- we use it too.  But I'm not sure that it works with the regular inverters

Ahh, you're probably right that they are micro inverters.  I just always forget the micro part.  =)
Title: Re: solar panel installation
Post by: MasterStache on March 14, 2016, 06:51:30 AM
I understand you paid a company to install the panels? I wonder what sort of cost savings you could have created by installing yourself.

I paid for installation.  When I was shopping in 2014, residential solar panel installations were about 50% materials and 50% labor/design/permitting.  You need a licensed electrician to install the power meters and required safety devices.  And the material cost can vary widely, depending on where you're getting your panels and inverters from.  In my case, I paid a premium for the (locally manufactured) hardware in order to qualify for the (much higher) in-state production incentive of 54 cents/kWh produced on the roof.

Hmm, I suppose the requirements vary by state. A licensed electrician wasn't required for me. I did have to get a local zoning permit, a building permit, and have it inspected by an electrical inspector. My county required a licensed structural engineer to examine my roof structure. That was a bit of a ridiculous cost. We didn't have any local or state incentives, sadly. Just the federal rebate. We did sell quite a few SREC's though.  I think the 50/50 labor/material cost seems about average for most installations. 

Also our utility provider swapped our meter for free. Took maybe a 1/2 hour or so.
Title: Re: solar panel installation
Post by: nawhite on March 14, 2016, 04:52:12 PM
Either I'm reading this wrong or the math is wrong:
We just bought a Nissan Leaf (http://forum.mrmoneymustache.com/welcome-to-the-forum/buying-a-nissan-leaf/) all-electric car.  If it drives 1000 miles/month at 3.9 kWh/mile, it will use 256 kWh of electricity at a cost of 7.41 cents per kWh.  That works out to 1.9 cents per mile, or $19/mo.  In a year of driving, the Leaf should use about 3000 kWh and cost us $230 in electricity.

Shouldn't that come out to 3900kWh/month? Where does the 256kWh come from? That would make it 28.9 cents per mile or $289/month, $3468/year.

Unrelated, my panels just had their first birthday so here's my annual recap:

3.125 kW system cost $7672 after tax rebate (http://forum.mrmoneymustache.com/welcome-to-the-forum/solar-panel-installation/msg838113/#msg838113)
Generated: ~3400 kWh
Additional used from grid: ~800 kWh
Total used: ~4200 kWh

Cost per kWh from utility: $0.13
Subsidy per generated kWh: $0.03

So total cost without panels would have been $546 for the year. With the panels, I paid the utility $104, and got back $102 in subsidies. So in total I saved $544. $544/$7672 = 7.09% return. (-2.99% for the loan we used to buy them so really only 4.1% return).

Not great, not terrible. Before our loan, it's right around the S&P500 inflation adjusted CAGR. It will probably remain right around that or trend slightly down as the panels get dirty and degrade a little. Usually utility rates go up over time which is where you make your real money, but here they just announced they are going to re-jigger the tiered rates so those who use the least get a discount and those who use the most have bills that go up which is good. But we were already among the lowest users so our bill would have gone down even without the panels (probably to around $0.11/kWh). Oh well. We get to feel fuzzy inside.

Title: Re: solar panel installation
Post by: sol on March 14, 2016, 07:01:35 PM
Either I'm reading this wrong or the math is wrong:
We just bought a Nissan Leaf (http://forum.mrmoneymustache.com/welcome-to-the-forum/buying-a-nissan-leaf/) all-electric car.  If it drives 1000 miles/month at 3.9 kWh/mile, it will use 256 kWh of electricity at a cost of 7.41 cents per kWh.  That works out to 1.9 cents per mile, or $19/mo.  In a year of driving, the Leaf should use about 3000 kWh and cost us $230 in electricity.

Shouldn't that come out to 3900kWh/month? Where does the 256kWh come from? That would make it 28.9 cents per mile or $289/month, $3468/year.

I typo'd the units.  The Leaf gets 3.9 miles per kWh, not kWh/mile.  So 1000 miles/mo divided by 3.9 miles/kWh is 256 kWh/month.

Title: Re: solar panel installation
Post by: monarda on August 01, 2016, 09:51:22 PM
Reviving this thread to see what you all think about this deal available to expand my system.
We've intended to (-some day-) expand our system, just wondering if now's the time.

How does $3.46 per watt sound for adding on 2.32 kW onto my system with microinverters?
That's before incentives.

That'll give us 4.24 kW total.
Title: Re: solar panel installation
Post by: sol on April 05, 2017, 08:10:36 PM
Every spring I find renewed personal interest in my solar panels, as they start ramping up production with the return of sunny weather.  Our panels (and thus this thread) are now almost three years old.

Net financial return thus far:  We paid $32,400 out of pocket in 2014 and then received $9720 in tax rebates and $4965 in production incentives the first year, and the maximum $5k production incentives in the second year, for a total cash payback thus far of $19,685.  It's hard to estimate the value of the free power we've been getting, but I'm ballparking it at $750/year (10,000 kWh at ~7.5 cents each).  All together, that's about 65% payback on our initial outlay, after 2.5 years.  By the time this August's incentive payment for 2016/17 arrives, that should rise to 83%.  By 2020 (when the system will be six years old) it should be ~130% payback, not counting residual value of the system or any future free power we get after that.

One of the amazing things to me is how much the prices of solar panels has come down, since we installed ours.  Residential solar panels appear to be dropping by about 10% per year, a rate that I would have thought was unsustainable three years ago when prices had already dropped so dramatically.  China is cranking out panels at a rate that will significantly alter the global energy industry within our lifetimes.  My system has only been more profitable than waiting out the price declines because we've been getting annual production incentives that (more than) offset the falling prices of new systems. 

There have been some hiccups along the way.  Last year my local utility company changed their fee structure, increasing the monthly connection fee from $5/mo to $10/mo while lowering the per kWh cost of power, which together cost me about $100/year.  And now they're talking about raising the connection fee to $16/mo over the next two years, but also raising the retail rate by a few percent, so those changes together will cost me about another $50/year.  Now that we're about energy neutral on an annual basis, the per kWh cost of power is basically irrelevant to us on a net basis, and we mostly worry about the monthly connection fee.  They are working hard to screw over residential solar power owners around here, which angers me because solar homeowners fronted the capital to provide my utility with capacity increases for which the utility gets federal subsidies, and now they are changing the rules under which we all made that decision.

One additional hiccup we've had is that one of our two inverters went offline in the middle of the dark months, and we didn't notice for about a month until our next power bill came in.  We lost about 400 kWh of production, which would normally have cost us about $200 in production incentives in our next check.  Fortunately, our system is a little oversized for the subsidy and we normally generate more than the maximum $5000 incentive, so I don't think it will actually hurt us as long as they stay functional through the summer months.

Attached Graph is net power consumption as measured by the power company.  It's a positive number in the winter, when we pay for power, and a negative number in the summer, when they pay us for power.  The seasonal sin wave is offset upwards in early 2016 when we bought the electric car, and will be unusually high for the billing periods covering our recent inverter failure.

 
Title: Re: solar panel installation
Post by: Ben Hogan on April 06, 2017, 06:26:21 AM
Sol, what city do you live in and who is your power company. Also can you post some pictures of the charge controller and connections?

Thanks.
Title: Re: solar panel installation
Post by: mistershankly on April 06, 2017, 11:22:15 AM
Our experience and setup is very similar to Sol's after two years of having the panels installed.

Has anyone installed or considered installing a battery like Tesla's Powerwall to store power for off-grid and non-peak sunlight days?
Title: Re: solar panel installation
Post by: nereo on April 18, 2017, 02:33:00 PM

One of the amazing things to me is how much the prices of solar panels has come down, since we installed ours.  Residential solar panels appear to be dropping by about 10% per year, a rate that I would have thought was unsustainable three years ago when prices had already dropped so dramatically.  China is cranking out panels at a rate that will significantly alter the global energy industry within our lifetimes.  My system has only been more profitable than waiting out the price declines because we've been getting annual production incentives that (more than) offset the falling prices of new systems. 


Sol - I'm curious if there would ever be a point when you'd swap out your panels for ones that are more efficient... maybe not today but perhaps in the future should efficiency and cost trends continue.  I'm thinking less about maximizing output during sunny summer days and more about 'raising the floor' during the shorter, rainy winter months.  guessing it would have to involve a complete change in your excess-production incentives.

Title: Re: solar panel installation
Post by: sol on April 18, 2017, 03:13:54 PM
Also can you post some pictures of the charge controller and connections?

Inside my garage there are two wall mounted inverters (left), next to a solar breaker box (middle) next to my regular circuit breaker box (right, inset in wall).  There is also an extra power meter for measuring total solar production, which is installed outside next to my regular net power meter.  The solar meter is currently counting upwards, because we're generating power.  The net power meter is currently spinning backwards because the sun is out and we're feeding power back into the grid.

One side effect of this arrangement is that we still have an incentive to conserve electricity, because we "pay" for every kWh we use.  On an annual basis we generate more than we use, and the power company pays us the retail power rate for our surplus (by applying it against our connection fees and water bill, since they are integrated).  So even though we don't use all the power we generate, if we were to leave more lightbulbs burning around here we would end up getting paid less for the surplus.
Title: Re: solar panel installation
Post by: sol on April 18, 2017, 03:26:58 PM
Sol - I'm curious if there would ever be a point when you'd swap out your panels for ones that are more efficient...

I would consider adding new panels to the system if I had a good place to put them, like an outbuilding or pagoda or something, but I don't think it makes sense to increase the efficiency of my current system at today's prices, or near-future prices.  Most of the payback I'm getting is from the state-sponsored 54 cents//kWh production incentive (which pays me $5k/year) and not from the free power we get (which pays me about $800/year).  When the state production incentive expires in 2020 and we're back to straigh retail power rates of ~8 cents/kWh, even doubling the efficiency of the panels would only make me another $800/year.  For an equivalent five year payback expectation, those double-efficient panels would have to drop to $4k installed.  That's 27 cents/kW installed, which is pretty far below any projections I've seen anywhere for the future cost of residential solar.

Fortunately, solar panels have long useful lifetimes even at severely degraded efficiencies, so old ones are likely to stay around a while.  There is always more available roof space for new panels, so I don't expect anyone to start upgrading their panel efficiencies until every valid roof in the country is covered.
Title: Re: solar panel installation
Post by: AllChoptUp on June 14, 2017, 12:14:59 PM
Thank you Sol and other contributors to this thread, I've learned so much! We are looking into solar for a South Florida home. Due to state energy lobbyists FL does not offer rebates/benefits so payback may shift quite a bit to the right. :(

Any South Fla folks on the thread willing to discuss their experience? Bonus points if in the Keys :)
Title: Re: solar panel installation
Post by: TomTX on June 14, 2017, 02:07:14 PM
Sol - I'm curious if there would ever be a point when you'd swap out your panels for ones that are more efficient... maybe not today but perhaps in the future should efficiency and cost trends continue.  I'm thinking less about maximizing output during sunny summer days and more about 'raising the floor' during the shorter, rainy winter months.  guessing it would have to involve a complete change in your excess-production incentives.

No point in removing old panels unless you are totally out of roof space. Waste of time and effort. If you need more panels due to age/loss of output - just add another panel or two to the existing system.
Title: Re: solar panel installation
Post by: Mrs. PoP on June 14, 2017, 05:43:21 PM
Thank you Sol and other contributors to this thread, I've learned so much! We are looking into solar for a South Florida home. Due to state energy lobbyists FL does not offer rebates/benefits so payback may shift quite a bit to the right. :(

Any South Fla folks on the thread willing to discuss their experience? Bonus points if in the Keys :)

We're s fl, but not Monroe county and got our installation a littl more than 2 years ago.   Ping me by pm if you wants details of our setup and costs, etc.  =)
Title: Re: solar panel installation
Post by: nereo on June 14, 2017, 06:47:19 PM
Sol - I'm curious if there would ever be a point when you'd swap out your panels for ones that are more efficient... maybe not today but perhaps in the future should efficiency and cost trends continue.  I'm thinking less about maximizing output during sunny summer days and more about 'raising the floor' during the shorter, rainy winter months.  guessing it would have to involve a complete change in your excess-production incentives.

No point in removing old panels unless you are totally out of roof space. Waste of time and effort. If you need more panels due to age/loss of output - just add another panel or two to the existing system.
Sol already answered, but I asked in part because it didn't seem like there was room on his roof to simply add more panels (look back alllllll the way on page 1)
Title: Re: solar panel installation
Post by: sol on June 14, 2017, 11:40:25 PM
Sol - I'm curious if there would ever be a point when you'd swap out your panels for ones that are more efficient... maybe not today but perhaps in the future should efficiency and cost trends continue.  I'm thinking less about maximizing output during sunny summer days and more about 'raising the floor' during the shorter, rainy winter months.  guessing it would have to involve a complete change in your excess-production incentives.

No point in removing old panels unless you are totally out of roof space. Waste of time and effort. If you need more panels due to age/loss of output - just add another panel or two to the existing system.

Sol already answered, but I asked in part because it didn't seem like there was room on his roof to simply add more panels (look back alllllll the way on page 1)

Nereo is right that I don't really have more room, with panels of these dimensions.

Personally, I'm not worried about "raising the floor" in the winter months because I'm grid-tied, and our power here is mostly hydropower anyway.  Remember that every part of the planet gets the same amount of sunlight on an annual basis, the poles just get six months of light and six months of dark.  It all averages out, though, so your latitude doesn't really matter much in terms of total watts received per year and if you're grid tied the winter deficiency isn't a problem.
Title: Re: solar panel installation
Post by: Prairie Stash on June 15, 2017, 11:02:26 AM
Sol - I'm curious if there would ever be a point when you'd swap out your panels for ones that are more efficient... maybe not today but perhaps in the future should efficiency and cost trends continue.  I'm thinking less about maximizing output during sunny summer days and more about 'raising the floor' during the shorter, rainy winter months.  guessing it would have to involve a complete change in your excess-production incentives.

No point in removing old panels unless you are totally out of roof space. Waste of time and effort. If you need more panels due to age/loss of output - just add another panel or two to the existing system.

Sol already answered, but I asked in part because it didn't seem like there was room on his roof to simply add more panels (look back alllllll the way on page 1)

Nereo is right that I don't really have more room, with panels of these dimensions.

Personally, I'm not worried about "raising the floor" in the winter months because I'm grid-tied, and our power here is mostly hydropower anyway.  Remember that every part of the planet gets the same amount of sunlight on an annual basis, the poles just get six months of light and six months of dark.  It all averages out, though, so your latitude doesn't really matter much in terms of total watts received per year and if you're grid tied the winter deficiency isn't a problem.
There is a caveat there, not every part of the earths surface receives equal sunlight (you can define planet as upper atmosphere or ground). If you live in a sunny part of Canada you can get more sunlight than Seattle for example. In North America the longitude makes more difference than latitude ;)

As a tangent, the newer versions of Climate change model predict increased cloud cover, which decreases solar potential for much of NA. Going forward to 2050 the effect may be larger in magnitude for parts of North America than the efficiency decline in solar panels (I'll need to research regional variations). While efficiency declines are real, the other part is the variation in solar hitting panels. 2050 is relevant as Sol is likely to still have the panels on his roof in 30 years.
https://www.nsf.gov/news/special_reports/clouds/question.jsp           laymans article
Title: Re: solar panel installation
Post by: sol on June 15, 2017, 11:31:08 AM
There is a caveat there, not every part of the earths surface receives equal sunlight (you can define planet as upper atmosphere or ground). If you live in a sunny part of Canada you can get more sunlight than Seattle for example.

PS is exactly right.  The problem with solar panels in my area isn't the latitude, it's the ~60% of days that are cloudy due to proximity to the ocean.  Those clouds reflect away lots of sunlight that could be powering my home.

On the bright side, locally made panels can be manufactured for optimal conversion efficiency under lower diffuse lighting conditions, rather than blazing sun.  My panels still generate more power annually than my household uses, even in grey rain land.  It's about 10,000 kWh per year, from 7560W of panels (28 panels at 270W each).
Title: Re: solar panel installation
Post by: MVal on July 18, 2017, 01:32:30 PM
Does anyone know anything about community solar farms? My local utility company has announced that coming soon will be opportunity to "lease" a solar panel at a local solar farm in exchange for a reduced electrical rate. Has anyone done this with their local utility company?
Title: Re: solar panel installation
Post by: Axecleaver on July 20, 2017, 12:20:34 PM
It's a way for them to capture the tax incentives and pass through a portion of it to the rate consumer. For example, a non-profit typically can't benefit from tax incentives on solar because they don't pay taxes. But a for-profit community solar farm can, and then a non-profit (or you) can lease a piece of that and enjoy the benefits.

Run the numbers and if it works, do it!
Title: Re: solar panel installation
Post by: frugalnacho on July 20, 2017, 02:41:15 PM
Sol - I'm curious if there would ever be a point when you'd swap out your panels for ones that are more efficient... maybe not today but perhaps in the future should efficiency and cost trends continue.  I'm thinking less about maximizing output during sunny summer days and more about 'raising the floor' during the shorter, rainy winter months.  guessing it would have to involve a complete change in your excess-production incentives.

No point in removing old panels unless you are totally out of roof space. Waste of time and effort. If you need more panels due to age/loss of output - just add another panel or two to the existing system.

Sol already answered, but I asked in part because it didn't seem like there was room on his roof to simply add more panels (look back alllllll the way on page 1)

Nereo is right that I don't really have more room, with panels of these dimensions.

Personally, I'm not worried about "raising the floor" in the winter months because I'm grid-tied, and our power here is mostly hydropower anyway.  Remember that every part of the planet gets the same amount of sunlight on an annual basis, the poles just get six months of light and six months of dark.  It all averages out, though, so your latitude doesn't really matter much in terms of total watts received per year and if you're grid tied the winter deficiency isn't a problem.

I don't think that's true.  You get the same amount of daylight, but not actual photons.  The closer you are to the equator the more direct the sun rays are, and you get more photons per unit of area. 
Title: Re: solar panel installation
Post by: nereo on July 20, 2017, 02:56:57 PM
Sol - I'm curious if there would ever be a point when you'd swap out your panels for ones that are more efficient... maybe not today but perhaps in the future should efficiency and cost trends continue.  I'm thinking less about maximizing output during sunny summer days and more about 'raising the floor' during the shorter, rainy winter months.  guessing it would have to involve a complete change in your excess-production incentives.

No point in removing old panels unless you are totally out of roof space. Waste of time and effort. If you need more panels due to age/loss of output - just add another panel or two to the existing system.

Sol already answered, but I asked in part because it didn't seem like there was room on his roof to simply add more panels (look back alllllll the way on page 1)

Nereo is right that I don't really have more room, with panels of these dimensions.

Personally, I'm not worried about "raising the floor" in the winter months because I'm grid-tied, and our power here is mostly hydropower anyway.  Remember that every part of the planet gets the same amount of sunlight on an annual basis, the poles just get six months of light and six months of dark.  It all averages out, though, so your latitude doesn't really matter much in terms of total watts received per year and if you're grid tied the winter deficiency isn't a problem.

I don't think that's true.  You get the same amount of daylight, but not actual photons.  The closer you are to the equator the more direct the sun rays are, and you get more photons per unit of area.

You are right in that total irradience is not the same in all locations, and is influenced by the angle of the sun (and cloud cover).  I'm left wondering what practical effect this has, though.  As I understand it output does not scale linearly with irradience.  In other words, the power output when it is 3000 E/m2 (typical of mid-day in the tropics) is not 50% more than when it is 'just' 2000E/m2 (values more typical of a sunny day in New England).

Where will you get better power output/day - somewhere where there's 18 hours of daylight but where the sun is at a steeper angle, or near the equator where you get a 12 hours, and several hours the sun is beating directly down on the panel.

Given the number of PV panels throughout Germany (latitude often >45) its still clearly 'worth it' in many locales. 
Title: Re: solar panel installation
Post by: sol on July 20, 2017, 03:04:41 PM
Sol - I'm curious if there would ever be a point when you'd swap out your panels for ones that are more efficient... maybe not today but perhaps in the future should efficiency and cost trends continue.  I'm thinking less about maximizing output during sunny summer days and more about 'raising the floor' during the shorter, rainy winter months.  guessing it would have to involve a complete change in your excess-production incentives.

No point in removing old panels unless you are totally out of roof space. Waste of time and effort. If you need more panels due to age/loss of output - just add another panel or two to the existing system.

Sol already answered, but I asked in part because it didn't seem like there was room on his roof to simply add more panels (look back alllllll the way on page 1)

Nereo is right that I don't really have more room, with panels of these dimensions.

Personally, I'm not worried about "raising the floor" in the winter months because I'm grid-tied, and our power here is mostly hydropower anyway.  Remember that every part of the planet gets the same amount of sunlight on an annual basis, the poles just get six months of light and six months of dark.  It all averages out, though, so your latitude doesn't really matter much in terms of total watts received per year and if you're grid tied the winter deficiency isn't a problem.

I don't think that's true.  You get the same amount of daylight, but not actual photons.  The closer you are to the equator the more direct the sun rays are, and you get more photons per unit of area.

I think this a geometry miscommunication.  The poles receive less energy per unit surface area of the planet, but not per unit surface area of the panels because the panels are tilted.  The area is different by the cos of the panel height.

There are other factors, of course. The poles are technically one earth radius farther away from the sun than the equator, so they receive very slightly less light by the inverse square law for distance.  And the ray path intersects more atmosphere at the poles because it comes in at a lower angle, so you get more scattering and absorption.  And the arc in the sky is longer at the poles, so they only receive the same amount of light if both locations were to use sun tracking panels.

But these are all details, compared to the amount of cloud cover you get in any location. 
Title: Re: solar panel installation
Post by: frugalnacho on July 20, 2017, 03:06:12 PM
Sol - I'm curious if there would ever be a point when you'd swap out your panels for ones that are more efficient... maybe not today but perhaps in the future should efficiency and cost trends continue.  I'm thinking less about maximizing output during sunny summer days and more about 'raising the floor' during the shorter, rainy winter months.  guessing it would have to involve a complete change in your excess-production incentives.

No point in removing old panels unless you are totally out of roof space. Waste of time and effort. If you need more panels due to age/loss of output - just add another panel or two to the existing system.

Sol already answered, but I asked in part because it didn't seem like there was room on his roof to simply add more panels (look back alllllll the way on page 1)

Nereo is right that I don't really have more room, with panels of these dimensions.

Personally, I'm not worried about "raising the floor" in the winter months because I'm grid-tied, and our power here is mostly hydropower anyway.  Remember that every part of the planet gets the same amount of sunlight on an annual basis, the poles just get six months of light and six months of dark.  It all averages out, though, so your latitude doesn't really matter much in terms of total watts received per year and if you're grid tied the winter deficiency isn't a problem.

I don't think that's true.  You get the same amount of daylight, but not actual photons.  The closer you are to the equator the more direct the sun rays are, and you get more photons per unit of area.

You are right in that total irradience is not the same in all locations, and is influenced by the angle of the sun (and cloud cover).  I'm left wondering what practical effect this has, though.  As I understand it output does not scale linearly with irradience.  In other words, the power output when it is 3000 E/m2 (typical of mid-day in the tropics) is not 50% more than when it is 'just' 2000E/m2 (values more typical of a sunny day in New England).

Where will you get better power output/day - somewhere where there's 18 hours of daylight but where the sun is at a steeper angle, or near the equator where you get a 12 hours, and several hours the sun is beating directly down on the panel.

Given the number of PV panels throughout Germany (latitude often >45) its still clearly 'worth it' in many locales.

Well that place getting 18 hours of daylight will only be getting 6 hours of daylight in 6 months.   I would expect that the location at the equator would have not only more stable power through the year (12 hours every day all year), but it would produce more power because it's getting far more actual energy than the higher latitude. 

I'm not a solar panel expert, but I gotta imagine it has a very real effect on the power generated even if it's not a linear scale.  I'm not saying it's not worth it anywhere but the equator, just pointing out that what Sol said isn't technically true.
Title: Re: solar panel installation
Post by: frugalnacho on July 20, 2017, 03:19:55 PM
I think this a geometry miscommunication.  The poles receive less energy per unit surface area of the planet, but not per unit surface area of the panels because the panels are tilted.  The area is different by the cos of the panel height.

There are other factors, of course. The poles are technically one earth radius farther away from the sun than the equator, so they receive very slightly less light by the inverse square law for distance.  And the ray path intersects more atmosphere at the poles because it comes in at a lower angle, so you get more scattering and absorption.  And the arc in the sky is longer at the poles, so they only receive the same amount of light if both locations were to use sun tracking panels.

But these are all details, compared to the amount of cloud cover you get in any location.

That will be true for any single panel in theory, but how do you arrange an entire array without running into practical limitations?  At my latitude there's about a 30% reduction in intensity vs the equator.  I'd have to have some pretty tall solar panels, and cast a large shadow on my neighbors house, in order to angle the entire square footage of my roof to match the intensity at the equator.   How could you even accomplish this at the poles? You'd just be building them sideways into space.
Title: Re: solar panel installation
Post by: sol on July 20, 2017, 03:27:47 PM
just pointing out that what Sol said isn't technically true.

Should I have included a picture on my explanation above about who it is true?  You're thinking about surface area of the ground, not surface area of the panel.  The farther north you go the more the panel is tilted toward vertical to have the same amount of cross sectional area exposed to the sun.  Same exposed area, same instantaneous power output.

Even at the literal pole in an idealized case, the panel would be mounted perfectly vertically and would get the same amount of instantaneous energy while the ground was getting zero.  Just because the earth gets less energy at the poles does not mean the panel gets less.

I'd have to have some pretty tall solar panels, and cast a large shadow on my neighbors house, in order to angle the entire square footage of my roof to match the intensity at the equator.   How could you even accomplish this at the poles? You'd just be building them sideways into space.

Fortunately, residential panels are typically built flush with your roof, and more northern climates already have more steeply pitched roofs.

I agree that panel shading is a problem for utility scale solar fields at high northern latitudes.  Fortunately we don't build them at the poles anyway, and such large scale installations are never designed to have 100% coverage anyway, because you need access to all of the panels.  Tilting them makes this easier, arguable allowing for more panels per acre off the equator than on it.
Title: Re: solar panel installation
Post by: frugalnacho on July 20, 2017, 05:27:46 PM
just pointing out that what Sol said isn't technically true.

Should I have included a picture on my explanation above about who it is true?  You're thinking about surface area of the ground, not surface area of the panel.  The farther north you go the more the panel is tilted toward vertical to have the same amount of cross sectional area exposed to the sun.  Same exposed area, same instantaneous power output.

Even at the literal pole in an idealized case, the panel would be mounted perfectly vertically and would get the same amount of instantaneous energy while the ground was getting zero.  Just because the earth gets less energy at the poles does not mean the panel gets less.

I'd have to have some pretty tall solar panels, and cast a large shadow on my neighbors house, in order to angle the entire square footage of my roof to match the intensity at the equator.   How could you even accomplish this at the poles? You'd just be building them sideways into space.

Fortunately, residential panels are typically built flush with your roof, and more northern climates already have more steeply pitched roofs.

I agree that panel shading is a problem for utility scale solar fields at high northern latitudes.  Fortunately we don't build them at the poles anyway, and such large scale installations are never designed to have 100% coverage anyway, because you need access to all of the panels.  Tilting them makes this easier, arguable allowing for more panels per acre off the equator than on it.

No I understand what you're saying, I typed that comment before your last post, even though it posted after you.
Title: Re: solar panel installation
Post by: dragoncar on July 21, 2017, 01:16:26 AM
just pointing out that what Sol said isn't technically true.

Should I have included a picture on my explanation above about who it is true?  You're thinking about surface area of the ground, not surface area of the panel.  The farther north you go the more the panel is tilted toward vertical to have the same amount of cross sectional area exposed to the sun.  Same exposed area, same instantaneous power output.

Even at the literal pole in an idealized case, the panel would be mounted perfectly vertically and would get the same amount of instantaneous energy while the ground was getting zero.  Just because the earth gets less energy at the poles does not mean the panel gets less.

I'd have to have some pretty tall solar panels, and cast a large shadow on my neighbors house, in order to angle the entire square footage of my roof to match the intensity at the equator.   How could you even accomplish this at the poles? You'd just be building them sideways into space.

Fortunately, residential panels are typically built flush with your roof, and more northern climates already have more steeply pitched roofs.

I agree that panel shading is a problem for utility scale solar fields at high northern latitudes.  Fortunately we don't build them at the poles anyway, and such large scale installations are never designed to have 100% coverage anyway, because you need access to all of the panels.  Tilting them makes this easier, arguable allowing for more panels per acre off the equator than on it.

Even better, at the pole you can just create a tower of panels 5 miles tall.  The effective irradiance per sq meter of land is enormous as long as you are willing to leave the ground!
Title: Re: solar panel installation
Post by: frugalnacho on July 21, 2017, 08:15:31 AM
Even better, at the pole you can just create a tower of panels 5 miles tall.  The effective irradiance per sq meter of land is enormous as long as you are willing to leave the ground!

(https://media.treehugger.com/assets/images/2011/10/solar20energy-jj-001.jpg.696x0_q70_crop-smart.jpg)
Title: Re: solar panel installation
Post by: MrSal on August 25, 2018, 10:44:17 AM
Sorry to revive this thread but after reading a bit about solar I was trying to see if it made sense installing them.

Sol's selling price per kWh back to the grid is amazing btw.

I was trying to figure out the rebates and incentives available to someone that lives in PA?

From the reading i was able to do, 30% Federal Rebate is guaranteed... how about any other rebates? I think utilities buy the electricity generated at a 1 to 1 ratio, so in essence, there is no free lunch here unfortunately - unless I saw it wrong.

Is there someone in PA that underwent the process of installing solar panels?
Title: Re: solar panel installation
Post by: nereo on August 25, 2018, 10:52:49 AM
@sol - update! update! update!
Title: Re: solar panel installation
Post by: TomTX on August 25, 2018, 12:49:44 PM
Sorry to revive this thread but after reading a bit about solar I was trying to see if it made sense installing them.

Sol's selling price per kWh back to the grid is amazing btw.

I was trying to figure out the rebates and incentives available to someone that lives in PA?

From the reading i was able to do, 30% Federal Rebate is guaranteed... how about any other rebates? I think utilities buy the electricity generated at a 1 to 1 ratio, so in essence, there is no free lunch here unfortunately - unless I saw it wrong.

Is there someone in PA that underwent the process of installing solar panels?
Ask your power provider how it works with them.
Title: Re: solar panel installation
Post by: Cadman on August 26, 2018, 01:29:54 PM
Yes, absolutely talk with your power company first as protocol varies PoCo to PoCo. Some offer rebates, some don't. Some will bank your credits, and some put a 12 month limit on them. Some cut you a check for excess each month, others don't. That's step 1.

For those that are handy, just this week Renvu was advertising a complete 7.5kW roof mount system for $1.575/watt, with Unirac racking and Solaria panels with micro-inverters. Might be a good deal for someone.


Title: Re: solar panel installation
Post by: sol on August 29, 2018, 04:03:08 PM
@sol - update! update! update!

update!

I haven't been paid yet for this year, and I'm grumpy about it.  Washington state's solar incentive program went through some administrative changes this year, and while they are in theory honoring the same deal, payment is supposed to be delayed up to two months.  I expect to get paid in October for the production year ending in June.

But my system is still maxing out my $5k/year rebate, so I'm happy.  Recall that I have twenty-eight 270 Watt panels on my roof, for a total of 7560 Watts of capacity.  Those panels need to generate at least 9260 kWh per production year in order to max out my rebate check (because they pay $0.54/kWh produced), which means my panels would need to see the equivalent of 1200 hours of full sun over the course of the year.  That's only 3.5 hours of full sun per day!

In reality, I probably get less than that in the rainy winters, but far more in the blazing hot summers. 

A quick check of my inverters in the garage suggests my roof has generated approximately 43 MWh since being installed in 2014.  This is significantly more than my total household usage since then, including replacing auto gasoline with an electric car and replacing natural gas heating with an electric heat pump.  At the national average of 15 cents per kWh, that 43 MWh is worth about $6500 of free electricity, but in reality my local power costs less than that due to existing hydropower surpluses, so it's probably more like $3500 of power. 

On top of the $3500 of free power, I have already received three $5k incentive payment checks and a $9,700 tax rebate.  After this year's incentive check arrives in October, my system will have more than paid for itself in 4 years and 3 months.  Going forward, I expect two more $5k incentive checks until the rebate program expires in 2020, and of course I will continue to get ~$800 of free electricity every year for the life of the panels.  Calculating an accurate ROI on this system is basically impossible because the returns are time-delayed and very lumpy, but suffice it to say I would have done better financially by putting the entire up-front cost into the stock market in early 2014, because the market has been bananas.

Compared to today's costs for solar panels, I dramatically overpaid back in 2014 (over $4 per Watt installed).  Remember from the OP that I paid extra for locally-made panels and inverters in order to get the higher incentive payments.  For someone looking to do something of similar size today, I would expect to pay much less up front, and also get much less back each year.  My system is sort of a historical oddity, by now.

In the graph below, I can clearly see the impact of replacing a bunch of gasoline consumption with an electric car (in 2016) and then replacing a bunch of natural gas consumption with an electric heat pump (in 2017).  Both of those have increased our household electricity consumption (though lowered our total costs) and I don't think that our household will continue to be net-negative for electricity going forward.  It will be close, though, and we may dip back into net negative territory after my kids start moving out in a few years.
Title: Re: solar panel installation
Post by: Prairie Stash on August 29, 2018, 05:46:35 PM
The ROI is hard. You put an undisclosed amount onto a 0% card for 9 months with a 1% cashback. You received 1/3 back in the first year - $5000+9720 ($14,720). Right now the growth on the outlay would be $16,000.

June 2014 S&P was 1947, today its 2914. If you reinvested each payment when you received it, how much would you get?
June 2015 to now, $14720, would have grown $5000.
June 2016 to now, $5000, growth $1800
June 2017 to now $5000 growth $800
October 2018 $5000
4 years power saving $3,200

I see at least $7600 in growth from reinvesting payments. Your system is paid for already (assuming reinvestments, but you're Sol so its a safe assumption).

When you get your check, you'll be $8000 behind leaving it in the market. But you get another 3 lumps of $5000 coming and residuals of $800/year for another 20 years.

I'm going out there saying you'll beat the market with this decision.

Reply#32
"My up front cost was 32,400.  That money is gone, so I'm $32,400 in the hole on day one.  Over the next six years I'll collect $30,000 in incentive payments, $9720 in tax rebate, and about $800/year in reduced power bills for a six year total of $44,520.

My $32,400 initial investment would have to grow at 6.56% per year to be worth $44,520 after six years, assuming annual compounding.

And my return should actually be a little better than that, because I'm getting about a third of that total ($9720+$5000+$800) back in the first year, not at the end"

Please check my math. Initially you pointed out that you should compare based on reinvestments, considering 1/3 was rebated upfront.
Title: Re: solar panel installation
Post by: sol on August 29, 2018, 06:01:28 PM
I did do a net present value calculation on my expected future payments, when I was first buying the solar panels, and decided the discounted repayments were worth about 3.2% per year.  At this point, I have no idea if that analysis is still anywhere near valid.  Looking back over this thread, there are too many complications to consider.  I'm pretty sure a creative accountant could justify six different answers, and I hate math problems with no right answer.

But as I've previously stated, I didn't buy solar panels solely as a profit-seeking venture.  There were environmental reasons, and fun technology toy reasons, and setting a good example for my kids reasons.
Title: Re: solar panel installation
Post by: monarda on August 30, 2018, 08:06:01 AM
But as I've previously stated, I didn't buy solar panels solely as a profit-seeking venture.  There were environmental reasons, and fun technology toy reasons, and setting a good example for my kids reasons.

Like.
:-)
Title: Re: solar panel installation
Post by: Prairie Stash on August 30, 2018, 08:56:29 AM
I did do a net present value calculation on my expected future payments, when I was first buying the solar panels, and decided the discounted repayments were worth about 3.2% per year.  At this point, I have no idea if that analysis is still anywhere near valid.  Looking back over this thread, there are too many complications to consider.  I'm pretty sure a creative accountant could justify six different answers, and I hate math problems with no right answer.

But as I've previously stated, I didn't buy solar panels solely as a profit-seeking venture.  There were environmental reasons, and fun technology toy reasons, and setting a good example for my kids reasons.
That's fair, I'm just pointing out that your NW, assuming the panels have $0 value, will be higher (not quite yet, therres still 2 tranches coming) then if you had left the money in the market. Sometimes you get rewarded for doing something good. Next time you're on your deck drinking a beer chilled by the sun, feel free to enjoy looking at them and seeing those panels as the one time you beat the market.

I think you're downplaying your success, let me congratulate you even if you don't want to hear it.
Title: Re: solar panel installation
Post by: sol on November 03, 2018, 01:17:30 PM
update:

I finally got paid for my 2017/18 production, the max $5k allowable by state law, and my solar panels have now more than paid for themselves since I started this thread.
Title: Re: solar panel installation
Post by: nereo on November 03, 2018, 02:18:04 PM

The summary is that we're installing twenty eight 270 watt panels on our south-facing roof, at a cost of $32,400 up front, to replace an estimated 75% of our home energy usage.  (edit 2015: turns out they replace more than 100% of our home energy use.)  This system should more than pay for itself before 2020, after which we will essentially be getting free energy.

update:

I finally got paid for my 2017/18 production, the max $5k allowable by state law, and my solar panels have now more than paid for themselves since I started this thread.

That's pretty freakin' awesome @sol - you've paid back your initial upfront cost more than a year sooner than estimated, and your energy production has more than eclipsed your usage since installation.
Title: Re: solar panel installation
Post by: monarda on November 03, 2018, 03:57:00 PM
Nice, sol!

Our much smaller system installed in Dec 2011 has produced 17 MWh, still exceeding expectations. What's your MWh total production since installation if I might ask?

Ours has not paid for itself yet, but we don't have as sweet a payback here in WI.
Title: Re: solar panel installation
Post by: sol on November 03, 2018, 06:58:21 PM
you've paid back your initial upfront cost more than a year sooner than estimated, and your energy production has more than eclipsed your usage since installation.

and

What's your MWh total production since installation if I might ask?

both need the same answer.  I installed about 7500 Watts of panels on my roof and expected to get about 7500 kWh of production per year, based on the estimates from websites and solar installers, but have instead been getting closer to 10,000 kWh per year. 

Since my panels went live in July of 2014, they have produced 42,834 kWh.  I just walked outside and looked at the production meter.  That's 42.8 MWh in 4.3 years, or just about 10 MWh per year, and it's been worth about $800 per year in avoided utility bills because we only pay about 8 cents per kWh instead of the national average of 12 cents/kWh.  That includes some down time when one of the inverters went out for a month and had to be replaced (under warranty, free to me).

Our household energy usage has also risen significantly since installation, almost doubling after we added the Leaf and replaced our gas furnace with the heat pump, but this still works out okay.  It turns out to be more cost effective for us to use that surplus solar power to displace the gasoline in our vehicle than to sell it back to the grid, so from a financial perspective we're shooting for net zero, with no surplus.  This year will be close.
Title: Re: solar panel installation
Post by: nereo on November 04, 2018, 07:46:56 AM
(asking here because you seem to keep on top of these things...)
since 2014 how has the hardware changed?  I hear there has been big drops in the cost of micro-converters... what about the panels themselves?  Seem to recall a lot of talk about how the goal for newer panels wasn't maximum output so much as better output during lower photo-intensity days (e.g. cloudy/rainy conditions).  Are 'model year 2018 panels' substantially better than the ones you put up in '14?
Title: Re: solar panel installation
Post by: TomTX on November 04, 2018, 08:36:50 AM
(asking here because you seem to keep on top of these things...)
since 2014 how has the hardware changed?  I hear there has been big drops in the cost of micro-converters... what about the panels themselves?  Seem to recall a lot of talk about how the goal for newer panels wasn't maximum output so much as better output during lower photo-intensity days (e.g. cloudy/rainy conditions).  Are 'model year 2018 panels' substantially better than the ones you put up in '14?

Panels have gotten cheap enough as a percentage of installed cost that it is becoming more common to "overprovision" by adding some extra panels, especially ones aimed East/West to increase early/late/overcast production. More likely to have the peak production clipped by hitting the max on your inverter, of course.

Panel quality, heat sensitivity and yield vary a lot.
Title: Re: solar panel installation
Post by: mycoding on May 03, 2020, 12:05:47 AM
  Interesting topic thank you.