5 ms·

I’ve been trying to do the math for my own home, are solar panels actually cash flow positive, once you account for efficiency decrease overtime etc.? It always

I’ve been trying to do the math for my own home, are solar panels actually cash flow positive, once you account for efficiency decrease overtime etc.? It always seemed like one barely breaks even in 2 decades

swid 4y ago
Sounds about right for the power only, but you also probably get a battery with it to deal with power outages… I don’t know how to price the utility of that, but it’s why I bought solar.
- Forgeties79 4y ago
  How long have you been able to stretch that battery out when your power is out? Don’t have a point to make or anything, I’m just curious. I hadn’t really considered that.
  - brianwawok 4y ago
    24kW can lost a long time if you don’t need AC. Should be days
  - swid 4y ago
    I only have 10kw but most days that is enough to get through the night. Air conditioning will go through it, but I don’t typically need it, especially after the sun sets.
- RosanaAnaDana 4y ago
  35k for a 8kwh, 24kwh battery storage system. ~15k in credits? Solar loan ends up at 175 a month. I got in before the recent ridiculousness around fuel prices. I'm sure I'm net positive at this point but haven't done the precise math. One addition I'm considering, is some bitcoin/ crypto rigs to take care of excess power during the peaks. Even with my batteries, I produce a lot of extra power and don't get paid spit from the power company, and what I do get I can only use as credit. https://www.nicehash.com/profitability-calculator/-bitmain-antminer-s17e-(64th) https://www.nicehash.com/profitability-calculator/-bitmain-a... Thing costs ~1.25k, but at ~$10/ day it will pay its self off in a quarter.
bombcar 4y ago
It can be cash flow positive if you do a bunch of the work yourself and plan accordingly. https://www.sevarg.net/tag/solar/ https://www.sevarg.net/tag/solar/ From my point of view the nice thing about it is reducing or eliminating recurring expenses. Once your recurring expenses drop below passive income you are pretty well set.
danans 4y ago
It depends on a whole lot of factors. In a sunny place like CA with good solar incentive programs, assuming good southern to southwestern exposure, they are cash positive after about 6 years [1]. In Wisconsin, 11 years [2]. In Washington State, 15 years [3] 1. https://www.energysage.com/solar-panels/ca/#:~:text=For%20California%2C%20the%20average%20solar%20payback%20period%20is%205.96%20years https://www.energysage.com/solar-panels/ca/#:~:text=For%20Ca.... 2. https://www.energysage.com/solar-panels/wi/#:~:text=In%20Wisconsin%2C%20the%20average%20solar%20payback%20period%20is%2011.90%20years https://www.energysage.com/solar-panels/wi/#:~:text=In%20Wis.... 3. https://www.energysage.com/solar-panels/wa/#:~:text=In%20Washington%2C%20the%20average%20solar%20payback%20period%20is%2014.55%20years https://www.energysage.com/solar-panels/wa/#:~:text=In%20Was....
- sib 4y ago
  Yeah, so far, with the rooftop system we put in about 1.5 years ago (Los Angeles), we are tracking to ~5.5 year payback period, so this feels right.
  - pie42000 4y ago
    Guaranteed 15%+ ROI. Really makes you wonder why more people aren't investing in solar
    - brianwawok 4y ago
      At what state? It’s more like 15-20 year break even by me; and I can’t sell power back to the grid.
- nightski 4y ago
  Wow is electricity really that expensive in CA? Our total expenditure on electricity over 20 years is around 20k. But in CA that site says that their net 20 year savings using solar is 44k-60k. That's insane. Their savings alone is 3 times the cost of our entire electric bill...
  - 4y ago
gxt 4y ago
Even if only just break even after 20years, it is an acceptable cost for freedom of mind and autonomy.
malchow 4y ago
Solar in California is often breakeven after 4 to 7 years. Enphase enables microgrid systems, and the IQ8 can keep your house powered even when the grid is down, and even without batteries –– something never before possible. https://enphase.com/sites/default/files/2021-10/IQ8SP-DS-0002-01-EN-US-2021-10-19.pdf https://enphase.com/sites/default/files/2021-10/IQ8SP-DS-000... Worth nothing that PG&E is working with CA Democrats to try to kill rooftop solar. They want renewables, but only if distributed using their (badly operated and overpriced) grid. [1] [1] https://pv-magazine-usa.com/2022/02/11/coalition-received-1-7-million-from-three-california-utilities-to-support-nem-3-0-a-rooftop-solar-killer/ https://pv-magazine-usa.com/2022/02/11/coalition-received-1-...
- hedora 4y ago
  I'm happy with our enphase system. We have batteties from them too. The Democrats (and Arnold) pushed back hard against the proposed NEM 3 rates that would have killed rooftop solar. I have nothing nice to say about PG&E.
- markvdb 4y ago
  While I can't say anything useful about PG&E, net metering is problematic though. As used right now in many regions of the world, it is a large and inefficient subsidy to relatively affluent solar roof owners like you and me. Where I live, a different regime is being introduced: - a capacity tariff: a base grid charge, calculated based upon quarterly average peak consumption - a feed-in rate: a wholesale rate compensation for injecting self-produced green electricity into the grid (my current rate: 0.064€/kWh) - a retail rate by one's electricity provider (my current rate: .02869€/kWh) - subsidies for installation of solar (up to 300€/kW peak) and storage (up to 30%) This at least conceptually incentivises both of solar installation and peak shaving. Solar is less ridiculously profitable for me, but still a no-brainer in terms of profitability.
ShakataGaNai 4y ago
Depends on how much power you need and your access to sun. I'm in the Bay Area, installed solar panels about 18 months ago. Break even for the panels is estimated to be about 6 years at current market rates. Now I also had to do a new roof, which roughly doubles the break even time, ignoring the fact that I'd have needed a new roof anyways. Currently I'm not taking into consideration decreased efficiency because the panels are warrantied for 90.08%+ at 25 years. Also something not taken into account on breakeven/cash positive is the fact that PG&E rates are always on the rise. As of March of this year rates went up 9%. The more rates go up, the faster I break even.
- brianwawok 4y ago
  You can take increasing rates , but then you also need to take opportunity cost. You paid say 50k cash for solar? Put that in SP500 for 6 years. It’s not 50k anymore.
  - tkojames 4y ago
    I got solar in northern California with new roof that needed to be replaced. I got 30 percent tax credit on the roof as well. Paid for the roof in cash but took 10 year loan out for the solar panels at 3.0 percent. Break even at this rate is about 4 years already a few year in. With inflation right now I feel like I got good deal borrowing the money. Right now my loan payment plus then 10.00 monthly connection fee is less than my average monthly bill before 2019. Not sure I would do it with needing a new roof though. But everybody experience will be different.
  - dap 4y ago
    You do, but it seems pretty good even taking into account opportunity cost? My calculations: https://news.ycombinator.com/item?id=31105389 https://news.ycombinator.com/item?id=31105389 Someone else said it better in a different subthread: https://news.ycombinator.com/item?id=31105120 https://news.ycombinator.com/item?id=31105120
    - brianwawok 4y ago
dap 4y ago
I got a quote last fall in the SF Bay Area for a system: - 6.4 kW (16x400W panels), microinverter-based (little to no maintenance expected in 25 years) - estimated to produce 8,500 kWh in year 1 - the panels are warrantied to produce 86% in year 25. Let's use 80% as a more conservative estimate. - up front cost: $16,500 after the federal tax incentive - alternative: paying PG&E $.25/kWh on average (conservative estimate) To a first approximation, the system would save $2,125 in the first year, or almost 13% of the initial investment. In year 25, we'd expect 6,800 kWh. At the same energy price, it'd be saving 10% of the initial investment. (This doesn't take into account inflation, changes in energy prices, and I'm sure other things. This is all very different if your local utility doesn't offer net metering, too.) The system breaks even in year 8, similar to what others in this thread have reported. But you can also look at it as a pretty low-risk investment returning 10-13% per year for 25 years. That sounds pretty good to me.
- FPGAhacker 4y ago
  The fact that the return is not compounding makes a very large difference here. $16,500 returning 10% of the original principle per year isn’t a great investment. 25 years you have $41,000 + 25 yr old solar panels. $16,500 returning 10% compounding over 25 years gets you $162,000 + the $16,500 principle. Considering opportunity cost spread evenly over 25 years, those panels cost over $5000 per year. There are plenty of reasons to go solar, but return on investment is not one of them.
  - dap 4y ago
    This is a good point!
    - Sankozi 4y ago
      No it is not. It assumes you store money gained under the bed and do not reinvest it in any way.
  - ninjinxo 4y ago
    You're not adjusting for inflation (cash + increases in electricity costs), ambitiously assuming an equivalent 10% return on other investments, or re-investing the amount saved per year in your calculations (that $1650 you save in the first year also compounds to ~$16.25k). Make those fixes and the numbers are much closer.

swid 4y ago

Sounds about right for the power only, but you also probably get a battery with it to deal with power outages… I don’t know how to price the utility of that, but it’s why I bought solar.

Forgeties79 4y ago
How long have you been able to stretch that battery out when your power is out? Don’t have a point to make or anything, I’m just curious. I hadn’t really considered that.
- brianwawok 4y ago
  24kW can lost a long time if you don’t need AC. Should be days
- swid 4y ago
  I only have 10kw but most days that is enough to get through the night. Air conditioning will go through it, but I don’t typically need it, especially after the sun sets.
RosanaAnaDana 4y ago
35k for a 8kwh, 24kwh battery storage system. ~15k in credits? Solar loan ends up at 175 a month. I got in before the recent ridiculousness around fuel prices. I'm sure I'm net positive at this point but haven't done the precise math. One addition I'm considering, is some bitcoin/ crypto rigs to take care of excess power during the peaks. Even with my batteries, I produce a lot of extra power and don't get paid spit from the power company, and what I do get I can only use as credit. https://www.nicehash.com/profitability-calculator/-bitmain-antminer-s17e-(64th) https://www.nicehash.com/profitability-calculator/-bitmain-a... Thing costs ~1.25k, but at ~$10/ day it will pay its self off in a quarter.

bombcar 4y ago

It can be cash flow positive if you do a bunch of the work yourself and plan accordingly. https://www.sevarg.net/tag/solar/ https://www.sevarg.net/tag/solar/ From my point of view the nice thing about it is reducing or eliminating recurring expenses. Once your recurring expenses drop below passive income you are pretty well set.

danans 4y ago

It depends on a whole lot of factors. In a sunny place like CA with good solar incentive programs, assuming good southern to southwestern exposure, they are cash positive after about 6 years [1]. In Wisconsin, 11 years [2]. In Washington State, 15 years [3] 1. https://www.energysage.com/solar-panels/ca/#:~:text=For%20California%2C%20the%20average%20solar%20payback%20period%20is%205.96%20years https://www.energysage.com/solar-panels/ca/#:~:text=For%20Ca.... 2. https://www.energysage.com/solar-panels/wi/#:~:text=In%20Wisconsin%2C%20the%20average%20solar%20payback%20period%20is%2011.90%20years https://www.energysage.com/solar-panels/wi/#:~:text=In%20Wis.... 3. https://www.energysage.com/solar-panels/wa/#:~:text=In%20Washington%2C%20the%20average%20solar%20payback%20period%20is%2014.55%20years https://www.energysage.com/solar-panels/wa/#:~:text=In%20Was....

sib 4y ago
Yeah, so far, with the rooftop system we put in about 1.5 years ago (Los Angeles), we are tracking to ~5.5 year payback period, so this feels right.
- pie42000 4y ago
  Guaranteed 15%+ ROI. Really makes you wonder why more people aren't investing in solar
  - brianwawok 4y ago
    At what state? It’s more like 15-20 year break even by me; and I can’t sell power back to the grid.
nightski 4y ago
Wow is electricity really that expensive in CA? Our total expenditure on electricity over 20 years is around 20k. But in CA that site says that their net 20 year savings using solar is 44k-60k. That's insane. Their savings alone is 3 times the cost of our entire electric bill...
- 4y ago

gxt 4y ago

Even if only just break even after 20years, it is an acceptable cost for freedom of mind and autonomy.

malchow 4y ago

Solar in California is often breakeven after 4 to 7 years. Enphase enables microgrid systems, and the IQ8 can keep your house powered even when the grid is down, and even without batteries –– something never before possible. https://enphase.com/sites/default/files/2021-10/IQ8SP-DS-0002-01-EN-US-2021-10-19.pdf https://enphase.com/sites/default/files/2021-10/IQ8SP-DS-000... Worth nothing that PG&E is working with CA Democrats to try to kill rooftop solar. They want renewables, but only if distributed using their (badly operated and overpriced) grid. [1] [1] https://pv-magazine-usa.com/2022/02/11/coalition-received-1-7-million-from-three-california-utilities-to-support-nem-3-0-a-rooftop-solar-killer/ https://pv-magazine-usa.com/2022/02/11/coalition-received-1-...

hedora 4y ago
I'm happy with our enphase system. We have batteties from them too. The Democrats (and Arnold) pushed back hard against the proposed NEM 3 rates that would have killed rooftop solar. I have nothing nice to say about PG&E.
markvdb 4y ago
While I can't say anything useful about PG&E, net metering is problematic though. As used right now in many regions of the world, it is a large and inefficient subsidy to relatively affluent solar roof owners like you and me. Where I live, a different regime is being introduced: - a capacity tariff: a base grid charge, calculated based upon quarterly average peak consumption - a feed-in rate: a wholesale rate compensation for injecting self-produced green electricity into the grid (my current rate: 0.064€/kWh) - a retail rate by one's electricity provider (my current rate: .02869€/kWh) - subsidies for installation of solar (up to 300€/kW peak) and storage (up to 30%) This at least conceptually incentivises both of solar installation and peak shaving. Solar is less ridiculously profitable for me, but still a no-brainer in terms of profitability.

ShakataGaNai 4y ago

Depends on how much power you need and your access to sun. I'm in the Bay Area, installed solar panels about 18 months ago. Break even for the panels is estimated to be about 6 years at current market rates. Now I also had to do a new roof, which roughly doubles the break even time, ignoring the fact that I'd have needed a new roof anyways. Currently I'm not taking into consideration decreased efficiency because the panels are warrantied for 90.08%+ at 25 years. Also something not taken into account on breakeven/cash positive is the fact that PG&E rates are always on the rise. As of March of this year rates went up 9%. The more rates go up, the faster I break even.

brianwawok 4y ago
You can take increasing rates , but then you also need to take opportunity cost. You paid say 50k cash for solar? Put that in SP500 for 6 years. It’s not 50k anymore.
- tkojames 4y ago
  I got solar in northern California with new roof that needed to be replaced. I got 30 percent tax credit on the roof as well. Paid for the roof in cash but took 10 year loan out for the solar panels at 3.0 percent. Break even at this rate is about 4 years already a few year in. With inflation right now I feel like I got good deal borrowing the money. Right now my loan payment plus then 10.00 monthly connection fee is less than my average monthly bill before 2019. Not sure I would do it with needing a new roof though. But everybody experience will be different.
- dap 4y ago
  You do, but it seems pretty good even taking into account opportunity cost? My calculations: https://news.ycombinator.com/item?id=31105389 https://news.ycombinator.com/item?id=31105389 Someone else said it better in a different subthread: https://news.ycombinator.com/item?id=31105120 https://news.ycombinator.com/item?id=31105120
  - brianwawok 4y ago

dap 4y ago

I got a quote last fall in the SF Bay Area for a system: - 6.4 kW (16x400W panels), microinverter-based (little to no maintenance expected in 25 years) - estimated to produce 8,500 kWh in year 1 - the panels are warrantied to produce 86% in year 25. Let's use 80% as a more conservative estimate. - up front cost: $16,500 after the federal tax incentive - alternative: paying PG&E $.25/kWh on average (conservative estimate) To a first approximation, the system would save $2,125 in the first year, or almost 13% of the initial investment. In year 25, we'd expect 6,800 kWh. At the same energy price, it'd be saving 10% of the initial investment. (This doesn't take into account inflation, changes in energy prices, and I'm sure other things. This is all very different if your local utility doesn't offer net metering, too.) The system breaks even in year 8, similar to what others in this thread have reported. But you can also look at it as a pretty low-risk investment returning 10-13% per year for 25 years. That sounds pretty good to me.

FPGAhacker 4y ago
The fact that the return is not compounding makes a very large difference here. $16,500 returning 10% of the original principle per year isn’t a great investment. 25 years you have $41,000 + 25 yr old solar panels. $16,500 returning 10% compounding over 25 years gets you $162,000 + the $16,500 principle. Considering opportunity cost spread evenly over 25 years, those panels cost over $5000 per year. There are plenty of reasons to go solar, but return on investment is not one of them.
- dap 4y ago
  This is a good point!
  - Sankozi 4y ago
    No it is not. It assumes you store money gained under the bed and do not reinvest it in any way.
- ninjinxo 4y ago
  You're not adjusting for inflation (cash + increases in electricity costs), ambitiously assuming an equivalent 10% return on other investments, or re-investing the amount saved per year in your calculations (that $1650 you save in the first year also compounds to ~$16.25k). Make those fixes and the numbers are much closer.