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I'm not so sure. Transmission losses and (AFAIK) infrastructure maintenance are also big costs. If I have rooftop solar, I probably have the most power at my p

I'm not so sure. Transmission losses and (AFAIK) infrastructure maintenance are also big costs. If I have rooftop solar, I probably have the most power at my peak usage, going straight into my air conditioning.

s1artibartfast 3y ago
Transmission losses are far lower than the cost of residential solar. National Grid transmission losses are around 5% of delivered power, while rooftop solar producers are paid 10 to 20 x the cost of commercial power production. Similarly, infrastructure and maintenance costs are fixed unless you are willing to go without power on a cloudy day or throughout the winter.
- RangerScience 3y ago
  Wait, what? :googles around: Ahhhh - the number living in my head from EE classes back on college was much, much higher - but apparently that's overall, not transmission: https://www.enerdynamics.com/Energy-Currents_Blog/How-Much-Primary-Energy-Is-Wasted-Before-Consumers-See-Value-from-Electricity.aspx https://www.enerdynamics.com/Energy-Currents_Blog/How-Much-P... Thank you! > infra & maintenance Right, right. My first expectation is that residential power usage is less on cloudy days, since lower AC needs. But, you're right to point out what you're pointing out - the drop in rooftop solar might be much greater than the corresponding drop in AC usage. My second expectation is that residential CA solar is almost entirely in places that don't get "winter" - which I guess in this case means 1) storms covering the sky and/or panels, 2) cold enough that heating power usage is significant, and 3) sun being lower in the sky means a reduction in power (I don't know how much tho)
  - s1artibartfast 3y ago
    >My second expectation is that residential CA solar is almost entirely in places that don't get "winter" Being in a cloudless area doesnt protect you from the rotation of the earth around the sun. Day length and solar angle still change. Even with ideal weather, California gets 50% less solar radiation in winter. Add weather on top and it is pretty typcial to get 10-20% of rooftop power in the winter. This means that the grid needs to be able to import 100% of the power when needed. Building and mainating the grid is essentially a fixed cost. Using the grid doesn't cost anything. Solar makes sense given that there is a big power load in the summers when the sun is shining. What doesn't make sense is buying power for $0.40/kWh from a homeowner mid summer when you have a grid connected power plant selling it for $0.02. We paid for the grid and need it either way, so we should use it.
  - dragonwriter 3y ago
    > My second expectation is that residential CA solar is almost entirely in places that don't get "winter" - which I guess in this case means 1) storms covering the sky and/or panels, 2) cold enough that heating power usage is significant, and 3) sun being lower in the sky means a reduction in power (I don't know how much tho) Er, every part of California has #3 (that’s just latitude), though its somewhat true that #2 and #1 are anticorrelated in that the coastal areas have more cloud cover but more moderate temperature and the inland valleys have more extreme temperatures (summer highs and winter lows) but less cloud cover, so much of the state doesnt get a the combinatiom of #1 and #2.
    - s1artibartfast 3y ago
      you also have to consider population distribution. Most people live on the coast with more cloud cover. This means rooftop solar is naturally distrubuted where it is less productive. This is one of many reasons why commerical solar is not buit on the coasts.
      - dragonwriter 3y ago
        > Most people live on the coast with more cloud cover. This means rooftop solar is naturally distrubuted where it is less productive. This assumes square meters of solar panels are distributed the same as population, which even as a first order approximation sounds highly suspect. An 800 sq. ft. apartment in San Francisco might house as many people as a 2,500 sq. ft. single floor house on a half-acre in the valley, but it won't support the same size solar array.
        s1artibartfast 3y ago
        I agree with your general point, but I think it is over shadowed by the sheer number of people adjacent to the coast. I wasn't able to dig it up easily, but I believe that if you looked at installed residential panel area, it would be strongly biased towards the coastal regions which contain the vast majority of the population.
  - hot_gril 3y ago
    Transmission loss is little. The bigger issue is the cost of maintaining transmission lines, but that's a problem we need to solve either way. Which PG&E has done a horrible job at.

s1artibartfast 3y ago

Transmission losses are far lower than the cost of residential solar. National Grid transmission losses are around 5% of delivered power, while rooftop solar producers are paid 10 to 20 x the cost of commercial power production. Similarly, infrastructure and maintenance costs are fixed unless you are willing to go without power on a cloudy day or throughout the winter.

RangerScience 3y ago
Wait, what? :googles around: Ahhhh - the number living in my head from EE classes back on college was much, much higher - but apparently that's overall, not transmission: https://www.enerdynamics.com/Energy-Currents_Blog/How-Much-Primary-Energy-Is-Wasted-Before-Consumers-See-Value-from-Electricity.aspx https://www.enerdynamics.com/Energy-Currents_Blog/How-Much-P... Thank you! > infra & maintenance Right, right. My first expectation is that residential power usage is less on cloudy days, since lower AC needs. But, you're right to point out what you're pointing out - the drop in rooftop solar might be much greater than the corresponding drop in AC usage. My second expectation is that residential CA solar is almost entirely in places that don't get "winter" - which I guess in this case means 1) storms covering the sky and/or panels, 2) cold enough that heating power usage is significant, and 3) sun being lower in the sky means a reduction in power (I don't know how much tho)
- s1artibartfast 3y ago
  >My second expectation is that residential CA solar is almost entirely in places that don't get "winter" Being in a cloudless area doesnt protect you from the rotation of the earth around the sun. Day length and solar angle still change. Even with ideal weather, California gets 50% less solar radiation in winter. Add weather on top and it is pretty typcial to get 10-20% of rooftop power in the winter. This means that the grid needs to be able to import 100% of the power when needed. Building and mainating the grid is essentially a fixed cost. Using the grid doesn't cost anything. Solar makes sense given that there is a big power load in the summers when the sun is shining. What doesn't make sense is buying power for $0.40/kWh from a homeowner mid summer when you have a grid connected power plant selling it for $0.02. We paid for the grid and need it either way, so we should use it.
- dragonwriter 3y ago
  > My second expectation is that residential CA solar is almost entirely in places that don't get "winter" - which I guess in this case means 1) storms covering the sky and/or panels, 2) cold enough that heating power usage is significant, and 3) sun being lower in the sky means a reduction in power (I don't know how much tho) Er, every part of California has #3 (that’s just latitude), though its somewhat true that #2 and #1 are anticorrelated in that the coastal areas have more cloud cover but more moderate temperature and the inland valleys have more extreme temperatures (summer highs and winter lows) but less cloud cover, so much of the state doesnt get a the combinatiom of #1 and #2.
  - s1artibartfast 3y ago
    you also have to consider population distribution. Most people live on the coast with more cloud cover. This means rooftop solar is naturally distrubuted where it is less productive. This is one of many reasons why commerical solar is not buit on the coasts.
    - dragonwriter 3y ago
      > Most people live on the coast with more cloud cover. This means rooftop solar is naturally distrubuted where it is less productive. This assumes square meters of solar panels are distributed the same as population, which even as a first order approximation sounds highly suspect. An 800 sq. ft. apartment in San Francisco might house as many people as a 2,500 sq. ft. single floor house on a half-acre in the valley, but it won't support the same size solar array.
      - s1artibartfast 3y ago
        I agree with your general point, but I think it is over shadowed by the sheer number of people adjacent to the coast. I wasn't able to dig it up easily, but I believe that if you looked at installed residential panel area, it would be strongly biased towards the coastal regions which contain the vast majority of the population.
- hot_gril 3y ago
  Transmission loss is little. The bigger issue is the cost of maintaining transmission lines, but that's a problem we need to solve either way. Which PG&E has done a horrible job at.