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Solar would better be considered solved when the companies installing it don’t require large loans, liens on your home, and door to door salespeople. It’d be ni

Solar would better be considered solved when the companies installing it don’t require large loans, liens on your home, and door to door salespeople. It’d be nice if having it installed was more similar to having a plumber or regular electrician stop by

szvsw 2y ago
I guess I meant from a technical efficiency perspective, rather than the social infrastructure around it. It’s unclear to me (and frankly seems unlikely?) that few more percentage points will fix the very real structural issues you raised! At the same time, even if we do solve those issues, and we get solar panels on the roof of every home, there are still significant challenges to overcome as it’s unlikely the average home can become fully energy independent (especially if there is electrified winter heating), and anyways, the energy demand from single-family residential housing is only one slice of the overall energy pie. In any case, it would certainly help if we did that!
derriz 2y ago
That's because putting solar on rooftops makes little economic sense. The overhead in terms of installation cost was relatively insignificant when PV panels cost 20 times as much - as they did 15 years ago. These days, the cost is swamped by installation costs. These days, the only place it makes sense to put PV is flat on unused or unproductive land. The 95% drop in PV panels means that it is no longer economic to bother with mechanical tracking in solar farms. Integrating panels into a domestic roof destroys the incredible cost advantages PV has over alternative power sources.
- grecy 2y ago
  I just installed 7.3kW on my roof, for a total out of pocket cost of $8000. (after rebates and free gov money) It looks like I'll make about $1000 of power per year, so I have an 8 year payback, after which I'll have free power for another ~20 years. How on earth does that make "little economic sense"?
  - throwaway14356 2y ago
    the funniest part is where we assume everything stays the way it is. Centralized systems are more efficient but have poor reliability. What if they just stop supplying power? What if a kwh costs $10?
  - szvsw 2y ago
    I think they probably meant from the perspective of society writ large. If you you are choosing between spending $10m on PV with the primary goal of decarbonization, are you better served by spending it on subsidizing rooftop PV or on utility scale PV? Probably the latter. > “In a base comparison, without considering subsidies, fuel prices, or carbon pricing, utility-scale solar and wind have the lowest LCOE of all sources. Utility-scale solar PV comes in anywhere from $24/MWh to $96/MWh, while onshore wind registers the lowest possible LCOE over the shortest range, from $24/MWh to $75/MWh. Offshore wind’s LCOE ranges between $72/MWh and $140/MWh. … Unsubsidized residential rooftop PV has an LCOE between $117/MWh and $282/MWh, while the LCOE of community and commercial and industrial (C&I) solar ranges between $49/MWh and $185/MWh. When factoring in federal tax subsidies under the US Inflation Reduction Act, including domestic contest provisions, rooftop PV comes in at $74/MWh to $229/MWh, and community/C&I rooftop PV at $32/MWh to $155/MWh.” [1] [1] https://www.pv-magazine.com/2023/04/14/average-solar-lcoe-increases-for-first-time-this-year/#:~:text=Unsubsidized%20residential%20rooftop%20PV%20has,%2FMWh%20and%20%24185%2FMWh https://www.pv-magazine.com/2023/04/14/average-solar-lcoe-in....
  - didgetmaster 2y ago
    People often do this calculation without considering the time value of money. If you took that same $8K you spent on your system and put it in a bank CD; you would earn about $420 each year in interest. That means your real savings for the solar system is only $580 a year, not $1000. That makes the payoff time expand from 8 years to nearly 14. Still might be worth it to you, but also might not.
    - fratlas 2y ago
      True, but consider grid electricity prices increasing over those decades too.
seventyone 2y ago
Plumbers and electricians will put liens on your home too

szvsw 2y ago

I guess I meant from a technical efficiency perspective, rather than the social infrastructure around it. It’s unclear to me (and frankly seems unlikely?) that few more percentage points will fix the very real structural issues you raised! At the same time, even if we do solve those issues, and we get solar panels on the roof of every home, there are still significant challenges to overcome as it’s unlikely the average home can become fully energy independent (especially if there is electrified winter heating), and anyways, the energy demand from single-family residential housing is only one slice of the overall energy pie. In any case, it would certainly help if we did that!

derriz 2y ago

That's because putting solar on rooftops makes little economic sense. The overhead in terms of installation cost was relatively insignificant when PV panels cost 20 times as much - as they did 15 years ago. These days, the cost is swamped by installation costs. These days, the only place it makes sense to put PV is flat on unused or unproductive land. The 95% drop in PV panels means that it is no longer economic to bother with mechanical tracking in solar farms. Integrating panels into a domestic roof destroys the incredible cost advantages PV has over alternative power sources.

grecy 2y ago
I just installed 7.3kW on my roof, for a total out of pocket cost of $8000. (after rebates and free gov money) It looks like I'll make about $1000 of power per year, so I have an 8 year payback, after which I'll have free power for another ~20 years. How on earth does that make "little economic sense"?
- throwaway14356 2y ago
  the funniest part is where we assume everything stays the way it is. Centralized systems are more efficient but have poor reliability. What if they just stop supplying power? What if a kwh costs $10?
- szvsw 2y ago
  I think they probably meant from the perspective of society writ large. If you you are choosing between spending $10m on PV with the primary goal of decarbonization, are you better served by spending it on subsidizing rooftop PV or on utility scale PV? Probably the latter. > “In a base comparison, without considering subsidies, fuel prices, or carbon pricing, utility-scale solar and wind have the lowest LCOE of all sources. Utility-scale solar PV comes in anywhere from $24/MWh to $96/MWh, while onshore wind registers the lowest possible LCOE over the shortest range, from $24/MWh to $75/MWh. Offshore wind’s LCOE ranges between $72/MWh and $140/MWh. … Unsubsidized residential rooftop PV has an LCOE between $117/MWh and $282/MWh, while the LCOE of community and commercial and industrial (C&I) solar ranges between $49/MWh and $185/MWh. When factoring in federal tax subsidies under the US Inflation Reduction Act, including domestic contest provisions, rooftop PV comes in at $74/MWh to $229/MWh, and community/C&I rooftop PV at $32/MWh to $155/MWh.” [1] [1] https://www.pv-magazine.com/2023/04/14/average-solar-lcoe-increases-for-first-time-this-year/#:~:text=Unsubsidized%20residential%20rooftop%20PV%20has,%2FMWh%20and%20%24185%2FMWh https://www.pv-magazine.com/2023/04/14/average-solar-lcoe-in....
- didgetmaster 2y ago
  People often do this calculation without considering the time value of money. If you took that same $8K you spent on your system and put it in a bank CD; you would earn about $420 each year in interest. That means your real savings for the solar system is only $580 a year, not $1000. That makes the payoff time expand from 8 years to nearly 14. Still might be worth it to you, but also might not.
  - fratlas 2y ago
    True, but consider grid electricity prices increasing over those decades too.

seventyone 2y ago

Plumbers and electricians will put liens on your home too