Author Topic: Solar Challenge: Net Zero  (Read 3031 times)

sol

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Re: Solar Challenge: Net Zero
« Reply #50 on: August 06, 2018, 03:20:30 PM »

for what the installers want for a basic grid tie roof mount system around here, I can install my own ground mount, significantly larger, DC coupled system with battery backup.  Which is next year's big project.

I would be super interested in reading that blog post.  Be sure to take good photos as you go, and then write it up for all of us dreamers.

Syonyk

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Re: Solar Challenge: Net Zero
« Reply #51 on: August 06, 2018, 03:45:02 PM »

for what the installers want for a basic grid tie roof mount system around here, I can install my own ground mount, significantly larger, DC coupled system with battery backup.  Which is next year's big project.

I would be super interested in reading that blog post.  Be sure to take good photos as you go, and then write it up for all of us dreamers.

Of course.  It'll probably be a several-part post with a summary at the end, like I did with my office (which, I suppose, is almost net zero - I need about 5-7 gallons a winter of gasoline for my generator, and about 3-4 gallons of propane, but it's pure solar the rest of the year, with a good bit of surplus spent on Folding@Home and BOINC).

My plan is to go with the Outback Radian ecosystem - a 48V, grid tie capable inverter, and build the rest of the system around that.  I'm going to have some massive ground mount A-frames for east-west panel facing (instead of the more common south), partly to lengthen the solar day for off grid use if needed, partly because I expect net metering to change at some point such that morning/evening production will be more valuable than solar noon production, partly because I get a tractor shed out of it if I do it right. ;)

I'm looking at around $30k-$35k materials cost, though I may be able to get significantly lower through some "I know a guy..." perks. 

The goal is ~unlimited grid down operation, though winter would obviously require a generator.  But I should be able to run 9-10 months of the year without the grid, if needed (I fully intend to export onto the grid when reasonable, but I can control the system to optimize this if/when net metering changes).

I don't know if it will ever "pay off" in terms of financial terms.  Our power is stupid-cheap (https://www.idahopower.com/service-and-billing/residential/pricing-2/idaho-residential-rates/) without much in the way of fixed fees, but I value uninterrupted power, and the learning that comes from putting something like this together.  I expect it's at least not going to be comically expensive, and, even with battery replacement at the 10-15 year mark, I should still be able to come out more or less even.  Especially if we add an electric car and replace some winter heat with biomass (which is a $5k project, by the time everything there gets installed - I'd have external combustion air).

And if I can make snarky comments about solar installers in the process, well... at this point, I consider that a minor bonus.

MasterStache

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Re: Solar Challenge: Net Zero
« Reply #52 on: August 06, 2018, 04:08:38 PM »
Hopefully the installed prices come down, because for what the installers want for a basic grid tie roof mount system around here, I can install my own ground mount, significantly larger, DC coupled system with battery backup.  Which is next year's big project.

When I got quotes for a solar array install back in early 2012, they wanted roughly 30K for roughly 5kW grid-tie. I went ahead and did it all myself for just under 15K. So I figured half was likely labor cost. 

sol

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Re: Solar Challenge: Net Zero
« Reply #53 on: August 06, 2018, 04:36:27 PM »
So I figured half was likely labor cost.

That's about what I found, too.  The cost of the panels, inverters, rails, and wiring was roughly half of the total cost.  The rest was labor, and business overhead like trucks and delivery, and little stuff like permits and inspections.

Another Reader

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Re: Solar Challenge: Net Zero
« Reply #54 on: August 06, 2018, 06:31:43 PM »
Those rates are insane.  We pay 7.5 cents per kWh including the delivery charge (but not the monthly hookup fee) and our power is already 97.5% carbon free.  Why do people still live in California?

edit:  I just looked it up and SCE only charges about $10/month for the connection fee (which they call the "minimum charge") and then charges up to 32 cents/kWh but that includes the minimum charge.  That makes it really hard to compare the cost of power, because we're using fundamentally different pricing schemes.  I'd have to build a spreadsheet to show costs for various levels of usage, and I'm guessing there might even be some (very low) usage levels at which SCE is cheaper than my local utility.  Unless they handle the tax credits and solar credits differnetly, which seems likely too.


yes it's hard to compare since we have different fixed and marginal costs.  Up until a few years ago we didn't have any fixed costs (solar changed that because lots of people were literally paying $0 per month while still being connected to the grid, and we were one of them). 

However, given our electricity usage rates before we went solar, our bills ranged from $20-75/month. It didn't make alot of sense for us to spend ~$10k on a solar system, but we did.  We are a fairly efficient household, but the cost of electricity is not a big reason to not live in CA (I know you were probably being somewhat facetious).  It's like water.  I'm sure in the PNW you can just leave your taps on all the time and not worry about it.  In CA, water conservation is expected, but honestly we still pay ridiculously low rates for water.

I'm going to guess you aren't on City of San Jose water.  Their rates are very high, which is why people in their service area are removing their grass and installing drought tolerant plants and rock.  Effectively, water rates are another property tax.  Most other South Bay water rates are high as well.  My electric bill is almost $200 a month in summer because of all the west facing glass and the need to use AC.  I agree to some extent about offsetting the higher tiers, but the tiers and the TOU periods are always subject to change.  My goal is to offset almost all of the electric bill, and if the incremental costs supports it, switching out the gas water heater for electric.

CCCA

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Re: Solar Challenge: Net Zero
« Reply #55 on: August 06, 2018, 08:19:32 PM »
Those rates are insane.  We pay 7.5 cents per kWh including the delivery charge (but not the monthly hookup fee) and our power is already 97.5% carbon free.  Why do people still live in California?

edit:  I just looked it up and SCE only charges about $10/month for the connection fee (which they call the "minimum charge") and then charges up to 32 cents/kWh but that includes the minimum charge.  That makes it really hard to compare the cost of power, because we're using fundamentally different pricing schemes.  I'd have to build a spreadsheet to show costs for various levels of usage, and I'm guessing there might even be some (very low) usage levels at which SCE is cheaper than my local utility.  Unless they handle the tax credits and solar credits differnetly, which seems likely too.


yes it's hard to compare since we have different fixed and marginal costs.  Up until a few years ago we didn't have any fixed costs (solar changed that because lots of people were literally paying $0 per month while still being connected to the grid, and we were one of them). 

However, given our electricity usage rates before we went solar, our bills ranged from $20-75/month. It didn't make alot of sense for us to spend ~$10k on a solar system, but we did.  We are a fairly efficient household, but the cost of electricity is not a big reason to not live in CA (I know you were probably being somewhat facetious).  It's like water.  I'm sure in the PNW you can just leave your taps on all the time and not worry about it.  In CA, water conservation is expected, but honestly we still pay ridiculously low rates for water.

I'm going to guess you aren't on City of San Jose water.  Their rates are very high, which is why people in their service area are removing their grass and installing drought tolerant plants and rock.  Effectively, water rates are another property tax.  Most other South Bay water rates are high as well.  My electric bill is almost $200 a month in summer because of all the west facing glass and the need to use AC.  I agree to some extent about offsetting the higher tiers, but the tiers and the TOU periods are always subject to change.  My goal is to offset almost all of the electric bill, and if the incremental costs supports it, switching out the gas water heater for electric.


Yeah, not in San Jose.  We're in the cool part of the SF Bay where no one has A/C.
Our water bill is high, but not because of the cost of water.  Looking at our last water bill the cost of water only was ~$16 for 3,740 gallons (2 months).  This is 0.4 cents per gallon or 235 gallons/$.  We took out our lawn, but not because of the cost of water.


We are a relatively efficient household, primarily for environmental reasons.  Once we were fairly efficient, the main utility costs at least for us, are primarily the fixed costs (having service) and not the variable costs of usage.

Roots&Wings

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Re: Solar Challenge: Net Zero
« Reply #56 on: August 07, 2018, 06:44:13 AM »
I'm in! Here in FL, average price per watt is $2.50 installed (or $1.75 post tax credit).


Hope to join you all and install a system designed for net zero in the next few months! Energysage.com has been really helpful with getting quotes.

Interesting graph.  When we had ours installed in 2012 our price per installed watt was close to $6/watt in CA.  However, the size of the system has a big impact I would think.  We had a very small installation (around 2.25kW) so there are a number of fixed costs and the installer indicated that our system was the minimum they would install.  Presumably if we'd installed a 7kW system instead we might have gotten a better price per watt.

Those are 2018 average installed prices from EnergySage.

I'm looking at installing a fairly small system (2.65 kW) to cover around 3,800 kWh/year usage. Only one small local company has provided a quote ($6,625 installed). Another company said their minimum size is 5 kW ($12.5k).

The net metering credits and power buy back are also quite interesting to see how this varies by location (2 cents and 7 cents have been mentioned). Here it would be a credit posted to the account in the month the excess energy is generated at the going electric rate of $0.10691 per kWh. So about a 10 year payback period in my case.

I'm a red panda

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Re: Solar Challenge: Net Zero
« Reply #57 on: August 07, 2018, 08:02:43 AM »
The cost was $3.25 per watt, or around $23,000, before the tax credit. 

Why do you want to know the cost before the tax credit?  Are you cash poor?

For example, my system cost about $32,000 up front, but then I got over $9k in tax refund the following April, and the state cuts me a check for $5k every year for the first six years.  My net cost was sort of negative, before accounting for the free power, unless you time-amortize the cost because I fronted the cash and then made money back in the future.  I certainly would have made more money investing $32k in the stock market in 2014 and paying my full utility bills since then.

Holy crap- that's phenomenal tax credits.  You're getting back more than you paid.
Our federal + state tax credits will cover about 50% of our upfront cost; but there is a "line" to get the tax credit back from the state, so we might not even get the money from them (and it's < $2k anyway)  for another 3-5 years.  It's about a 10 year payback period for us because of this and the low electric rates in our state.  But that's OK with me.

We won't net zero though. We designed the system to cover 80% of our needs. The thought was that solar will be cheaper in the future, so if our needs increase we can add on later.  Our company trues up every month, not annually- so to cover 100% we'd way over produce in the summer, and the buy back rate is wholesale (2.2 cents), so it would be a long time to cover the cost of the extra panels to make up for the lower production in the winter.
« Last Edit: August 07, 2018, 09:30:52 AM by I'm a red panda »

Arbitrage

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Re: Solar Challenge: Net Zero
« Reply #58 on: August 07, 2018, 08:14:06 AM »
I'd probably be on board, but since I'm about 85% sure we're going to move to FIRE within a few years (far lower than the payoff period, in all likelihood), I'm no longer looking at an install.  Too bad, really, since our house is a great candidate (large southern-facing roof with minimal tree cover, sunny SoCal).  I know we could potentially get trued-up on the install cost at house sale, but I don't really want to take that risk, especially with our house already being one of the most expensive in the neighborhood.

That, plus DW's desire to upgrade the kitchen pronto.  At least I've talked her out of a full remodel, but I'm still steeling myself for ~$20k in lost potential retirement savings.  Yes, once again, perhaps we'll make some of it back.  Hopefully it doesn't end up being more than that number.

MasterStache

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Re: Solar Challenge: Net Zero
« Reply #59 on: August 07, 2018, 11:02:55 AM »
I'd probably be on board, but since I'm about 85% sure we're going to move to FIRE within a few years (far lower than the payoff period, in all likelihood), I'm no longer looking at an install.  Too bad, really, since our house is a great candidate (large southern-facing roof with minimal tree cover, sunny SoCal).  I know we could potentially get trued-up on the install cost at house sale, but I don't really want to take that risk, especially with our house already being one of the most expensive in the neighborhood.

That, plus DW's desire to upgrade the kitchen pronto.  At least I've talked her out of a full remodel, but I'm still steeling myself for ~$20k in lost potential retirement savings.  Yes, once again, perhaps we'll make some of it back.  Hopefully it doesn't end up being more than that number.

Just make sure you find a another house with great solar potential as well. That was my only regret about moving. Our current house is terrible for solar. It's the only thing I miss about our old house.

Syonyk

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Re: Solar Challenge: Net Zero
« Reply #60 on: August 07, 2018, 11:04:53 AM »
Just make sure you find a another house with great solar potential as well. That was my only regret about moving. Our current house is terrible for solar. It's the only thing I miss about our old house.

Why?  Generally, "terrible for solar" means things like "Well shaded from the summer sun, so cooling costs are low anyway." :)

MasterStache

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Re: Solar Challenge: Net Zero
« Reply #61 on: August 07, 2018, 11:09:22 AM »
Just make sure you find a another house with great solar potential as well. That was my only regret about moving. Our current house is terrible for solar. It's the only thing I miss about our old house.

Why?  Generally, "terrible for solar" means things like "Well shaded from the summer sun, so cooling costs are low anyway." :)

East/West oriented roof. Not really much shade either. Nowhere to pole mount an array. Yeah our house is smaller than our previous so energy bills really aren't bad. 

Syonyk

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Re: Solar Challenge: Net Zero
« Reply #62 on: August 07, 2018, 11:52:08 AM »
East/West oriented roof. Not really much shade either. Nowhere to pole mount an array. Yeah our house is smaller than our previous so energy bills really aren't bad.

If anything, that's better for solar the way things are likely to be going.  South facing optimizes kWh per panel production, but power demand on the grid is highest in the morning/evening.  So as net metering likely changes to get away from pure 1:1 kWh credits, putting more panels up east/west facing may be quite useful. :)

Livethedream

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Re: Solar Challenge: Net Zero
« Reply #63 on: August 08, 2018, 09:37:22 AM »
Solar production has been down about 30% because of all the fires covering the sky with smoke in Northern California. The only benefit is the smoke cloud layer has slightly dropped temperatures as well.

Syonyk

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Re: Solar Challenge: Net Zero
« Reply #64 on: August 08, 2018, 10:00:01 AM »
Smokey skies and hot temperatures are rough in my office. :/

MasterStache

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Re: Solar Challenge: Net Zero
« Reply #65 on: August 08, 2018, 10:24:10 AM »
East/West oriented roof. Not really much shade either. Nowhere to pole mount an array. Yeah our house is smaller than our previous so energy bills really aren't bad.

If anything, that's better for solar the way things are likely to be going.  South facing optimizes kWh per panel production, but power demand on the grid is highest in the morning/evening.  So as net metering likely changes to get away from pure 1:1 kWh credits, putting more panels up east/west facing may be quite useful. :)

Yeah but power production is reduced by roughly 20%. So weather it's beneficial or not in the future would depend on a lot of things, one being projected time in residence. We have less than 10 years left before my spouse retires and we move to a LCOL area. 

Syonyk

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Re: Solar Challenge: Net Zero
« Reply #66 on: August 08, 2018, 10:48:00 AM »
We plan to stay here forever. So long term planning.

My goal is stuff that will mostly last the rest of my life. So I do overbuild.