Author Topic: Solar panels should come online tomorrow!  (Read 9990 times)

CALL 911

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Solar panels should come online tomorrow!
« on: December 22, 2014, 06:22:29 AM »
So the company has been finishing up the installation of the 4kw system on my roof. Should be finished by noon. Then, the county has to come and sign off on the work.

Then I get green(er) power with a 7-8 year payback! Not the best thing ever, but not bad.

Only thing is, around here when I mention it, I kinda get the side eye from people. You know, when they aren't sure what to think of you, but they know you just aren't "right", but can't explain how.

Maybe you guys will understand. Yea! Solar!

Roots&Wings

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Re: Solar panels should come online tomorrow!
« Reply #1 on: December 22, 2014, 07:58:37 AM »
Totally excited for you!  Would love to see a brief financial breakdown of costs/estimated payback if you might be willing to share. 

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Re: Solar panels should come online tomorrow!
« Reply #2 on: December 22, 2014, 08:00:48 AM »
Nice!  Are you net metering or running batteries?

Runge

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Re: Solar panels should come online tomorrow!
« Reply #3 on: December 22, 2014, 08:17:27 AM »
Totally excited for you!  Would love to see a brief financial breakdown of costs/estimated payback if you might be willing to share.

+1

If it's ok to ask, where are you living?

skunkfunk

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Re: Solar panels should come online tomorrow!
« Reply #4 on: December 22, 2014, 08:58:13 AM »
I kinda want to do this, but I'm averaging under $100 a month for electricity. Hard to justify either that or my project to insulate the attic!

MarcherLady

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Re: Solar panels should come online tomorrow!
« Reply #5 on: December 22, 2014, 09:01:24 AM »
Congratulations, Call 911.  We put a 3.33kw system up about 15 months ago & it's been really satisfying to watch the bills come down.  We are also focusing on using electricity while the sun is shining and have put the dishwasher & washing machine on timers, which started out as a bit of a pain, but has turned into second nature over the year.  We also have got better at staggering our use, ie we don't switch everything on at once, because that involves <gasp> buying power!  There's something about having to plan your power use that makes you more aware of the wonderful luxury that it really is to flick a switch and have heat/light/whatever!

Bob W

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Re: Solar panels should come online tomorrow!
« Reply #6 on: December 22, 2014, 09:15:58 AM »
Yes please tell us the details -- cost, where you live etc...  I could never get this come close to penciling out in my area. 

It is cool as shit though. 

agent_clone

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Re: Solar panels should come online tomorrow!
« Reply #7 on: December 23, 2014, 02:26:38 AM »
I kinda want to do this, but I'm averaging under $100 a month for electricity. Hard to justify either that or my project to insulate the attic!
Ditto, my last bill for electrity was $AU135 for the quarter. About $75 of that was network charges.  When battery technology gets cheaper it would be a maybe to avoid the network charges depending on if I can have gas without electricity.

Bob W

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Re: Solar panels should come online tomorrow!
« Reply #8 on: December 23, 2014, 08:04:11 AM »
I kinda want to do this, but I'm averaging under $100 a month for electricity. Hard to justify either that or my project to insulate the attic!
Ditto, my last bill for electrity was $AU135 for the quarter. About $75 of that was network charges.  When battery technology gets cheaper it would be a maybe to avoid the network charges depending on if I can have gas without electricity.

Yeah,  I think in my situation that if I was on gas for heat, dryer and stove and drastically monitored and cut electric by using pretty much only LED lights and an efficient fridge,  it might be worth it to do the battery/solar set up.   The charges on my bill not actually usage are around $25 just to be hooked up.   So for 25 times 12 my annual would be 300 just to stay hooked up.   If I translate that by a factor of 6 I could rationalize $1,800 in batteries.   Not sure what kinda backup that would get me. 

In my area,  in the winter, I could easily imagine 6 days with no sun and then some spotty sun. 

But for those of you in CA or the South --  this solution makes money sense.

Remember the cost of power has been going up well in advance of inflation  -- so if you're paying $100 today I could see $200 in 7 years and $400 in 14 and $$800 in 21 years.   Yikes!  That hurts thinking about it.

Bob W

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Re: Solar panels should come online tomorrow!
« Reply #9 on: December 23, 2014, 08:19:15 AM »
This just in for you bikers -

Pedal-A-Watt

http://www.econvergence.net/

It appears that 2 adults could generate around 600 watts if they each bike generated for 1 hour per day.

Let's see 600 watts would power 3 LED lights for 20 hours but wouldn't be enough to power my fridge for 24 hours unfortunately.   

I guess I could go with an upright fridge and cut that by 75%  or I could use the outside in the winter and forego the fridge.  Crap,  my fridge is a condiment cooler about 80% of the time anyhow.  I've gone for 90 days in the summer without one,  so I should be able to figure out how to go the whole winter without one.   It rarely gets above 40 here from Dec - Mar anyway and that is the time the sun is gone.

So theoretically,  if I was propane for heat, stove, dryer (optional anyway), and did away with the need for a fridge in the winter,  and was very watt efficient with lights, TVs, computers, etc.  I could power my house with a modest solar, battery and bike-a-watt system.   Hmmm?   

The reason I'm interested is that I dream of building a super efficient Tiny House (800 sq ft) at some point and would hope to have zero power and water bills.   The amount of heat a tiny house needs if properly sealed and insulated is minimal. 

Now if I can just get the wife to minimize her 1500 watt hair dryer usage. 

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Re: Solar panels should come online tomorrow!
« Reply #10 on: December 23, 2014, 01:19:19 PM »
Nice!  Are you net metering or running batteries?

Neither. In my part of coastal SC, the state run utility has the most bizarre solar rules I've ever heard of. When I called the utility to clarify the rules, as I must have terribly misunderstood them, the solar point of contact correctly used the word "draconian".

In a nutshell, if you elect to try to sell your excess power back to the grid, you have to sign up for their "plan". The draconian part is that after a $24.00/mo distribution charge, and a ~$0.05/kWH energy charge, they have a demand charge. For fun, lets go with the high demand time (summer). To calculate the demand charge, take the rate ($11.34) and multiply it by the highest peak time (early afternoon/evening) electric draw in kW. Lets say the water heater kicks on (3k) at the same time the AC is running (4k), while a hairdryer is being used (1.5k), and the pool pump is on (1k) when someone turns on the oven and stove to cook dinner (2.8k). Then, foolishly, the kids start the dryer (4.4k). We haven't even turned on a light, radio, TV, alarm clock, etc. All of these occur at the same moment for a total of 16.7 kW. Doesn't matter if it's for a second or 3 hours. 16.7 x $11.34= $189. Then do it again for off peak times (morning and night) and multiply by $4.85. Granted, the draw would be offset a bit by the solar panels, but you can be looking at a $400 bill before buying a single kW.

Shockingly, ONE person has signed up for this plan in 2 years. The other options are to buy batteries to store the power, or not send it back to the grid. So around here, nobody bothers to net meter/net bill. Basically, any excess power you generate is gone. So the few people with grid tied systems size them so there is very little if any surplus power generated.

For the math, I took the system size and looked at a solar hours map and figured out what I'd generate, and multiplied it by the $0.11/kWH they charge. I took the after rebate cost of the system and divided by the expected monthly savings, thus estimated the time to payback. I ignored any appreciation in the house due to the system, or costs for replacing failed components.

And due to weather delays, it won't be live until Monday now. :(

Gerard

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Re: Solar panels should come online tomorrow!
« Reply #11 on: December 23, 2014, 02:17:26 PM »
So the few people with grid tied systems size them so there is very little if any surplus power generated.

This gives me an opening to ask all y'all smart people something I've wondered about home electrical systems: Can you efficiently store energy without storing electricity? As in, would it make sense to have any electricity you're producing but not using shunted over to, say, a large-tank hot water heater, so that your excess power is warming up 200 gallons of water that will later help heat your house?

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Re: Solar panels should come online tomorrow!
« Reply #12 on: December 23, 2014, 03:18:39 PM »
That really depends on your goals and situation. If you want to heat your home, sure, you can send the excess power to a heating element to heat water.

MMM just put a radiant floor system in his house. You could include a storage tank with separate controls for the heating elements and circulating pump. Heat the water all day, pump it around all day and night. If you're off the grid, in Alaska, it might make a lot of sense. If your on the grid in Florida, I can't see how it will help. How much heat do you need in summer? How much extra electricity do you want to make in winter, just to heat your water?

CCCA

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Re: Solar panels should come online tomorrow!
« Reply #13 on: December 23, 2014, 08:36:21 PM »
Congrats on the new system. I remember when we put our panels in and we couldn't wait till it all got connected and hooked up.
Does your system come with a way to track your generation online?  That was the most interesting aspect for me, tracking in real time our generation.

We have enphase micro inverters which can also send data to PVOutput which is a great way to aggregate your data.

Here's a post on our blog which describes our solar system. I've been meaning to update with newer info and I'll get around to it at some point.

« Last Edit: December 25, 2014, 10:50:35 PM by CCCA »

skunkfunk

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Re: Solar panels should come online tomorrow!
« Reply #14 on: December 24, 2014, 09:52:59 AM »
That really depends on your goals and situation. If you want to heat your home, sure, you can send the excess power to a heating element to heat water.

MMM just put a radiant floor system in his house. You could include a storage tank with separate controls for the heating elements and circulating pump. Heat the water all day, pump it around all day and night. If you're off the grid, in Alaska, it might make a lot of sense. If your on the grid in Florida, I can't see how it will help. How much heat do you need in summer? How much extra electricity do you want to make in winter, just to heat your water?

One of the local utilities around here stores energy by pumping water up a dam at night. They then get it back at peak pricing by running their turbines with it.

With a mere 4000 gallon tank up 100 meters in the air, you could store 4 kWH ! That's enough for a mustachian to make it half a day or so without sunlight!

MrFrugalChicago

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Re: Solar panels should come online tomorrow!
« Reply #15 on: December 24, 2014, 11:13:22 AM »
This just in for you bikers -

Pedal-A-Watt

http://www.econvergence.net/

It appears that 2 adults could generate around 600 watts if they each bike generated for 1 hour per day.


As a pretty serious biker..  not that many people can hold 300 watts for an hour. How much power you can hold for 1 hour when fully rested is called your FTP, and you have to be really good (not pro as they could hold closer to 400 watts), but at least semi pro.. or really fat (for a 300 pound person, 300 watts is not that big of a deal because they have a lot more muscle mass).

Realistically a decent recreational biker of healthy weight that bikes 1 hour a day is going to average 175-200 watts for a male, and 150-175 watts for a female. So you would really make more like 300-400 watts per day, which is basically nothing.

CCCA

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Re: Solar panels should come online tomorrow!
« Reply #16 on: December 24, 2014, 12:56:00 PM »
This just in for you bikers -

Pedal-A-Watt

http://www.econvergence.net/

It appears that 2 adults could generate around 600 watts if they each bike generated for 1 hour per day.


As a pretty serious biker..  not that many people can hold 300 watts for an hour. How much power you can hold for 1 hour when fully rested is called your FTP, and you have to be really good (not pro as they could hold closer to 400 watts), but at least semi pro.. or really fat (for a 300 pound person, 300 watts is not that big of a deal because they have a lot more muscle mass).

Realistically a decent recreational biker of healthy weight that bikes 1 hour a day is going to average 175-200 watts for a male, and 150-175 watts for a female. So you would really make more like 300-400 watts per day, which is basically nothing.


I can't really comment on the sustained power output numbers, but more of didactic point on units:  watts are a unit of power output, which is a rate.  when you generate power for a given amount of time, this translates into energy.  So 200 watts (power) for 2 hours (time) is 400 watt-hours (energy).  Also equivalent to about 4 cents of electricity (at 10cents per kilowatt hour (kWh)). 
So while it may be good for losing weight and getting fit, it's not going to save you much money. 


A 60 watt solar panel generating for about 6-7 hours in sunlight would generate about the same amount of daily energy (400 watt hours).  Our solar panel system is 2.25 kW or 2250 watts.  Our system averages about 11 kWh per day (11,000 watt hours).


scottish

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Re: Solar panels should come online tomorrow!
« Reply #17 on: December 26, 2014, 12:24:03 PM »
Quote
One of the local utilities around here stores energy by pumping water up a dam at night. They then get it back at peak pricing by running their turbines with it.

With a mere 4000 gallon tank up 100 meters in the air, you could store 4 kWH ! That's enough for a mustachian to make it half a day or so without sunlight!

Energy storage seems to be the big problem with these systems in terms of going off the grid.   I'd love to see a good solution for this!

It seems to me that the trouble with storing it in a water tank is you have to maintain the water tank, you have to maintain the pump and then you have to maintain a generator to reuse the energy.   And then you lose energy converting the potential energy of all that water back into electricity.     Wikipedia says that water turbines can exceed 90% mechanical efficiency though - this is way better than I would have guessed.   But I wonder - why doesn't the utility just reduce the flow of water over the dam in the first place?

This fellow here:

http://physics.ucsd.edu/do-the-math/2012/07/my-modest-solar-setup/

build a lead-acid battery setup for storage.   But he found that the battery lifetime wasn't good enough to be cost effective.

None of this detracts from using solar energy to reduce your electric bill.    If anyone has an off-the-grid system working, that would be a very interesting discussion.

gaja

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Re: Solar panels should come online tomorrow!
« Reply #18 on: December 26, 2014, 12:52:43 PM »
In January, we are moving to a town where they claim to have actual sunshine in the summer months. We are more used to grey skies and dark winters, and haven't bothered looking into solar before. But now it could make sense, and I'm looking for good advice. We will be needing hot water year round, both for heating the house and washing, and electricity. I'm thinking about some sort of hybrid system with solar heat and fireplace with a water jacket, and a few solar panels for fun. We have an electric car, so we could use the batteries in that to store surplus energy.

skunkfunk

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Re: Solar panels should come online tomorrow!
« Reply #19 on: December 26, 2014, 01:23:43 PM »
Quote
One of the local utilities around here stores energy by pumping water up a dam at night. They then get it back at peak pricing by running their turbines with it.

With a mere 4000 gallon tank up 100 meters in the air, you could store 4 kWH ! That's enough for a mustachian to make it half a day or so without sunlight!

Energy storage seems to be the big problem with these systems in terms of going off the grid.   I'd love to see a good solution for this!

It seems to me that the trouble with storing it in a water tank is you have to maintain the water tank, you have to maintain the pump and then you have to maintain a generator to reuse the energy.   And then you lose energy converting the potential energy of all that water back into electricity.     Wikipedia says that water turbines can exceed 90% mechanical efficiency though - this is way better than I would have guessed.   But I wonder - why doesn't the utility just reduce the flow of water over the dam in the first place?

This fellow here:

http://physics.ucsd.edu/do-the-math/2012/07/my-modest-solar-setup/

build a lead-acid battery setup for storage.   But he found that the battery lifetime wasn't good enough to be cost effective.

None of this detracts from using solar energy to reduce your electric bill.    If anyone has an off-the-grid system working, that would be a very interesting discussion.

My whole spiel there was farcical. A tank suspended 100 meters in there is probably not even legal. I'd guess ten meters might be as high as you can get it, and with a smaller tank at that. Essentially, useless.

MarcherLady

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Re: Solar panels should come online tomorrow!
« Reply #20 on: December 26, 2014, 01:53:17 PM »
would it make sense to have any electricity you're producing but not using shunted over to, say, a large-tank hot water heater, so that your excess power is warming up 200 gallons of water that will later help heat your house?

Our spare electricity powers our hot water tank by way of an immersion heater, thereby reducing our gas bill.  During the summer we had enough hot water for a household of 2 with no gas usage on about 80% of days.  Look at Immersun devices for more information.

scottish

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Re: Solar panels should come online tomorrow!
« Reply #21 on: December 26, 2014, 05:02:05 PM »
Quote
My whole spiel there was farcical. A tank suspended 100 meters in there is probably not even legal. I'd guess ten meters might be as high as you can get it, and with a smaller tank at that. Essentially, useless.

Huh, I thought you meant to pump it up a hill, not suspend it in mid-air.     Oklahoma isn't that flat is it?

kib

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Re: Solar panels should come online tomorrow!
« Reply #22 on: December 26, 2014, 05:19:32 PM »
I have a 3K grid tied system and love the savings.  I believe a full 12 months will have us paying only admin and distribution costs of about $15 per month - we run a huge overage during the winter and bank much more by being on grid than we possibly could with batteries.  For a while I owned a house that was completely off grid with a .5K system run on 'golf cart' batteries - southern AZ.   It's not impossible, but you basically need a way around heavy energy use, i.e. tiny propane hot water tank, solar oven, small wood stove, hang drying clothes etc.  The cost and size of a system that will run and back up a standard all-electric house in real time is enormous.

sol

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Re: Solar panels should come online tomorrow!
« Reply #23 on: December 28, 2014, 08:36:33 PM »
This gives me an opening to ask all y'all smart people something I've wondered about home electrical systems: Can you efficiently store energy without storing electricity? As in, would it make sense to have any electricity you're producing but not using shunted over to, say, a large-tank hot water heater, so that your excess power is warming up 200 gallons of water that will later help heat your house?

About two years ago there was a large scale study to study this exact idea.  A power company that had excess generating capacity  at some times wanted to know if they could use residential hot water heaters as a sort of grid battery for load leveling, a place to stash power so that in times of high demand those electric water heaters wouldn't kick on.  It turned out to be far more cost effective than using residential electric vehicle batteries, but there were still some problems.

Chief among them was that residential hot water heaters are typically not designed to hold 200 degree F water.   The power company had to pay to retrofit the homes with temperature regulators to avoid scalding people, and there was significant power loss due to uninsulated water heaters losing heat to their environment, typically unheated garages and basements.

I wish I could still find the link.  Ultimately they decided that it only made sense in places that were primarily served by electric heat rather than natural gas, and also had very peaky loads that could benefit from a little bit of load leveling by reducing peak demand and suplementing with excess power when they had excess generation, which isn't very many places.   And of course it required the installation of a smart grid system to control the power delivery, so there are really only a handful of neighborhoods nationwide that were well suited for it.

puglogic

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Re: Solar panels should come online tomorrow!
« Reply #24 on: December 28, 2014, 09:37:46 PM »
We have a 4.5KW system (since 2012, in Colorado)  and locked into a contract when Xcel Energy was still paying 0.15 per kwh.

They hate us now.  All those billboards they've put up about "doing solar right" ?   That's because of people like me, who took them up on their years of sales pitches and put panels up, and thus are taking them to the cleaners.   Now we pay 30-50% of our previous bills, and get a check for $40-90/month on top of that.  And got in in time to get the Fed tax credit.

And to Xcel I say: waaaaah. 

Thanks for the tip on the Immersun.  Hmmmmm......

gaja

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Re: Solar panels should come online tomorrow!
« Reply #25 on: December 29, 2014, 07:05:40 AM »
This gives me an opening to ask all y'all smart people something I've wondered about home electrical systems: Can you efficiently store energy without storing electricity? As in, would it make sense to have any electricity you're producing but not using shunted over to, say, a large-tank hot water heater, so that your excess power is warming up 200 gallons of water that will later help heat your house?

About two years ago there was a large scale study to study this exact idea.  A power company that had excess generating capacity  at some times wanted to know if they could use residential hot water heaters as a sort of grid battery for load leveling, a place to stash power so that in times of high demand those electric water heaters wouldn't kick on.  It turned out to be far more cost effective than using residential electric vehicle batteries, but there were still some problems.

Chief among them was that residential hot water heaters are typically not designed to hold 200 degree F water.   The power company had to pay to retrofit the homes with temperature regulators to avoid scalding people, and there was significant power loss due to uninsulated water heaters losing heat to their environment, typically unheated garages and basements.

I wish I could still find the link.  Ultimately they decided that it only made sense in places that were primarily served by electric heat rather than natural gas, and also had very peaky loads that could benefit from a little bit of load leveling by reducing peak demand and suplementing with excess power when they had excess generation, which isn't very many places.   And of course it required the installation of a smart grid system to control the power delivery, so there are really only a handful of neighborhoods nationwide that were well suited for it.

This is a bit larger scale than the original poster, but a friend of mine is working on the El Hierro project in the Canary Islands. They are trying to only use renewables, no fossil fuels: http://www.dailymail.co.uk/sciencetech/article-2614804/Spanish-island-world-powered-entirely-wind-water.html

In addition to what the article mentions, they will use the desalination plant to regulate the energy consumption (produce more in peak periodes, shut down production when there is no wind or sun), convert to electric transport, and maybe use hydrogen to store excess energy.

skunkfunk

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Re: Solar panels should come online tomorrow!
« Reply #26 on: December 29, 2014, 11:34:31 AM »
Quote
My whole spiel there was farcical. A tank suspended 100 meters in there is probably not even legal. I'd guess ten meters might be as high as you can get it, and with a smaller tank at that. Essentially, useless.

Huh, I thought you meant to pump it up a hill, not suspend it in mid-air.     Oklahoma isn't that flat is it?

It's pretty flat, you'd be hard pressed to find a 100 meter hill. It's not "flat" but it is in most any given small area.

This gives me an opening to ask all y'all smart people something I've wondered about home electrical systems: Can you efficiently store energy without storing electricity? As in, would it make sense to have any electricity you're producing but not using shunted over to, say, a large-tank hot water heater, so that your excess power is warming up 200 gallons of water that will later help heat your house?

About two years ago there was a large scale study to study this exact idea.  A power company that had excess generating capacity  at some times wanted to know if they could use residential hot water heaters as a sort of grid battery for load leveling, a place to stash power so that in times of high demand those electric water heaters wouldn't kick on.  It turned out to be far more cost effective than using residential electric vehicle batteries, but there were still some problems.

Chief among them was that residential hot water heaters are typically not designed to hold 200 degree F water.   The power company had to pay to retrofit the homes with temperature regulators to avoid scalding people, and there was significant power loss due to uninsulated water heaters losing heat to their environment, typically unheated garages and basements.

I wish I could still find the link.  Ultimately they decided that it only made sense in places that were primarily served by electric heat rather than natural gas, and also had very peaky loads that could benefit from a little bit of load leveling by reducing peak demand and suplementing with excess power when they had excess generation, which isn't very many places.   And of course it required the installation of a smart grid system to control the power delivery, so there are really only a handful of neighborhoods nationwide that were well suited for it.

One of the rural co-ops has been selling home generators and having their electricians install them all over. They retain control and maintenance of them and switch them on for peak shaving.

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Re: Solar panels should come online tomorrow!
« Reply #27 on: January 07, 2015, 04:51:08 PM »
Yea! They're on! I've made $3.50 worth of electricity.
WOOHOO! Dinners on me! (For me alone. At Taco Bell.)

I'm just glad to be doing my part for the world, and hopefully my wallet as well.

But I still envy you people in Oregon.

Songbird

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Re: Solar panels should come online tomorrow!
« Reply #28 on: January 11, 2015, 12:13:45 PM »
Awesome news! We have talked and talked about going solar here but the payback time is so long.

So happy for you!

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Re: Solar panels should come online tomorrow!
« Reply #29 on: January 30, 2015, 11:14:00 AM »
Puglogic, that incentive is amazing! We just had our system installed this week and our Xcel incentive is $0.02/kWh. Way less than your 15 cents. Still worth it for us though as I'll spell out below.

A lot of people have been asking for an in depth analysis of the costs for a system so here is mine for the 3kW system we just installed:

For reference: we live in Denver, gas heat furnace and water heater, electric stove, electric clothes dryer. Currently, our electricity costs 11 cents per kWh but we were paying extra to get our energy from wind (b/c Colorado gets about 70% of its electricity from coal) so that cost became 13.2 cents per kWh.

The electric company gives us a $0.02/kWh incentive for each kWh generated and we also benefit from net metering (in the summer when we generate more than we use, we can bank a credit to use towards our bills in the winter, when we use more than we generate). So we get $0.152 from lower bills and incentive for every single kWh generated.

Given our location and house orientation (mostly west facing roof mount) etc, NREL's PVWatts calculator (http://pvwatts.nrel.gov/pvwatts.php) says our 3kW (really 3.12 kW because we got twelve 260W panels) should generate 4,363 kWhs in an average year. This is worth $663.17 per year on average.

Our system cost $12,175. Federal tax credit drops that by 30%. We also got a $500 Visa gift card for giving them two referrals and signing the contract within 2 days (they used it as a high pressure salesman technique: "if you don't sign in the next two days, you wont get the $500!!!"). One of our referrals also decided to get a system which gave us another $300 gift card. So total out of pocket for us is $7722. We did $1000 down and then they let us finance the rest at 2.99%

For numbers people:
Costs:
$12,175 - 30% tax credit= $8522 - $800 referral bonus = $7722 total out of pocket costs
$6722 is financed at 2.99% so $201 in interest the first year.

Benefits:
4363 kWh/year * $0.02 production incentive (good for 10 years) = $87.26/year
4363 kWh/year * $0.132 cost of electricity but this goes up every year = $575.92/year ($480 if we didn't pay extra for wind power)
total = $663/year

663-201/7722 = ~6% return on investment that will go up as electricity gets more expensive and as I pay less in interest each year

But really if you think of it as a leveraged investment, I only put $1000 down, and I'm still going to get $462 in benefits this year and every year, so its really a 46.2% return on investment. i.e unbelievably good!
« Last Edit: January 30, 2015, 11:16:43 AM by nawhite »

sol

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Re: Solar panels should come online tomorrow!
« Reply #30 on: January 30, 2015, 09:34:02 PM »
663-201/7722 = ~6% return on investment that will go up as electricity gets more expensive and as I pay less in interest each year

I went through a similar process when doing the math on our solar system, but I think your calculation (and mine, originally) is missing something important.

I agree that you're earning 6% of your investment back each year.  The problem is that this is NOT comparable to 6% growth of another investment, because your principal is gone.  If you invested $10k in a stock and it went up 6%, you really have $10,600.  If you invested $10k in solar panels and get $600 back in the first year, you really have $600.

So in your example you're getting $462 in net payments every year so you would need the thing to run for 16 years before you break even on your $7722 outlay.  From that perspective, your return this year was (7722-462)/7722 or -94%, not +6%.

I guess you can sort of claim the "value" of the installed solar system as part of your home equity, but we all know the resale value on installed solar is a lot less than the purchase price, and then it depreciates every year.

Our system was significantly bigger, and more expensive, but our incentives are slightly better.  We wrote a $32k check, and get annual net payments of about $4600.  The 30% federal tax credit knocks our out-of-pocket costs down to $22.4 (if you ignore the six month lag to get the tax refund back) so I figure we need to run for five years in order to break even (since 5 * 4600 > 22,400).  After five years, we'll start making a profit.  Until then, we're operating at a loss.

And it gets even worse.  If I had put that $32k into the stock market and earned an average of 7%, after five years I'd have almost $45k instead of just breaking even on my $32k investment in solar panels, so I'll still be "behind" even after they pay for themselves.

I don't mean to be discouraging.  I love my solar panels and don't regret the decision to put them up, and I commend you for doing so.  But from a purely economical perspective, they're not a slam dunk.  Installers will sometimes pitch misleading math to potential customers by highlighting the apparently high "rate of return" instead of actual dollars in hand. 

Syonyk

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Re: Solar panels should come online tomorrow!
« Reply #31 on: January 31, 2015, 05:28:36 PM »
Gah, stop thinking of everything in electricity.

A bicycle tied to a generator is a terrible way of doing almost everything you want to do.  If it requires mechanical energy, hook it straight to the bicycle.  If it can't be done any way but electricity, it's OK, but don't be silly.  As an example, running a blender on bike-generated electricity is radically less-efficient than just hooking a blender to a bike frame for mechanical energy.

Same goes for long term energy storage.  You *can* heat a water tank with solar generated electricity, but you'll be radically better off if you just build a hot water solar system to heat the water directly.  I guess running a tank with solar electricity is better than just dumping it, but barely.

If you're off grid, doing as much as you can without going through the intermediate stage of "electricity" improves efficiency a lot.  The only reason we do that is because it makes sense with a large power grid, and a non-trivial amount of the electric company paying builders to put in electric everything.  Electric baseboard heat is a stupid way to heat a house, but for some reason, it's popular with the electric companies.  Can't imagine why...

Long term energy storage is just a tough problem.  If you are power station sized, molten salt isn't a terrible option, but I don't think many people would be interested in a 1000C+ blob of molten salt at home.  It turns out, storing it in the form of compressed carbon is really very hard to beat.

BlueMR2

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Re: Solar panels should come online tomorrow!
« Reply #32 on: February 01, 2015, 11:24:57 AM »
I kinda want to do this, but I'm averaging under $100 a month for electricity. Hard to justify either that or my project to insulate the attic!

Same here, plus I have a roof of unknown age.  I hate to do a solar install on top of this roof then have to rip it all up and re-do it again.  I also hate to preventively replace a roof that may have years of good life left.  Argh!  :-)

nawhite

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Re: Solar panels should come online tomorrow!
« Reply #33 on: February 03, 2015, 06:04:39 PM »
663-201/7722 = ~6% return on investment that will go up as electricity gets more expensive and as I pay less in interest each year

I went through a similar process when doing the math on our solar system, but I think your calculation (and mine, originally) is missing something important.

I agree that you're earning 6% of your investment back each year.  The problem is that this is NOT comparable to 6% growth of another investment, because your principal is gone.  If you invested $10k in a stock and it went up 6%, you really have $10,600.  If you invested $10k in solar panels and get $600 back in the first year, you really have $600.

So in your example you're getting $462 in net payments every year so you would need the thing to run for 16 years before you break even on your $7722 outlay.  From that perspective, your return this year was (7722-462)/7722 or -94%, not +6%.

I guess you can sort of claim the "value" of the installed solar system as part of your home equity, but we all know the resale value on installed solar is a lot less than the purchase price, and then it depreciates every year.

Our system was significantly bigger, and more expensive, but our incentives are slightly better.  We wrote a $32k check, and get annual net payments of about $4600.  The 30% federal tax credit knocks our out-of-pocket costs down to $22.4 (if you ignore the six month lag to get the tax refund back) so I figure we need to run for five years in order to break even (since 5 * 4600 > 22,400).  After five years, we'll start making a profit.  Until then, we're operating at a loss.

And it gets even worse.  If I had put that $32k into the stock market and earned an average of 7%, after five years I'd have almost $45k instead of just breaking even on my $32k investment in solar panels, so I'll still be "behind" even after they pay for themselves.

I don't mean to be discouraging.  I love my solar panels and don't regret the decision to put them up, and I commend you for doing so.  But from a purely economical perspective, they're not a slam dunk.  Installers will sometimes pitch misleading math to potential customers by highlighting the apparently high "rate of return" instead of actual dollars in hand.

Yeah every housing market is different as far as resale value of the panels goes. Around me, depreciation on panels is basically non-existant (those who want panels on a house they are buying don't really look at the age of the panels, they just look at the fact the house has panels, like granite counters and stainless steel appliances.) Smart buyers will look at the energy bills and take the monthly savings and back that out with their mortgage rate to see how much more they should be willing to pay (saves $500/year, 4% mortgage rate = house worth $12,500 more minus some for maintenance). And the increase in home equity (from looking at comparables with and without panels in my neighborhood) is closer to the up front pre-tax credit cost not the lower cost to me.

We are actually planning on selling (or renting depending on market conditions) in about 3 years and I fully expect to get at least $8000 more for the house because it has panels on it, but like I said, every market is different.

DavidAnnArbor

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Re: Solar panels should come online tomorrow!
« Reply #34 on: February 04, 2015, 06:42:30 PM »
Well I think it's great you are using solar energy because even though it may not be the most lucrative economic choice to make, you're doing a lot to help with global climate change, and it's very satisfying to know that! Also, I think the solar panels protect the roof shingles.

sol

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Re: Solar panels should come online tomorrow!
« Reply #35 on: February 04, 2015, 07:00:35 PM »
Well I think it's great you are using solar energy because even though it may not be the most lucrative economic choice to make, you're doing a lot to help with global climate change

I also really enjoy using my solar powered blender, my solar powered washing machine, and my solar powered refrigerator.   Solar panels have made everything electric in my house more awesome.

MoneyCat

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Re: Solar panels should come online tomorrow!
« Reply #36 on: February 04, 2015, 07:25:16 PM »
Our solar panels are going to be installed over the next two days.  It's going to be a 3.5kW system that should generate more than enough power for all our needs.  We're also getting 15 years of SRECs to sell to help offset the cost of the system along with the tax rebate on our 2015 taxes.  It should take us about 8 years to pay off the cost of the system with energy savings and incentives and we're looking forward to free electricity from now on.