5 ms·

Rooftop photovoltaic can (and will) cover local needs. Bigger issue is local energy storage (eg. community batteries).

by grumpy-de-sre 2y ago

closewith 2y ago
This is absurd. There's no limit to energy needs - they only grow.
- IndrekR 2y ago
  Sure there are reasonable limits. Where, is another matter. For example, I can not imagine a reasonable use-case for 1MW power-line per single apartment.
  - detourdog 2y ago
    I was required to wire each unit with 150kW panel. The original 1931 service was 240 x 200 Amps which I upgraded to 240 x 800 Amps in 2018. I posted the best image I could of the original 1931 schematic which has 9 circuits for 5,000 sqft school. It's the first image in this slide show. https://www.icloud.com/sharedalbum/#B2dGIcgc2GugpW3 https://www.icloud.com/sharedalbum/#B2dGIcgc2GugpW3
    - IndrekR 2y ago
      Interesting. That is like 52 sqm per unit, which is 2.9 kW/sqm — three times higher power density than the solar irradiance on earth surface. If this is used at full power, how are the rooms cooled? (most energy gets converted to heat in typical use-cases)
      - detourdog 2y ago
        I’m not completely following your comment but in 1954 they added a 7,000 sqft addition. We are using mini-splits for HVAC.
        IndrekR 2y ago
        Almost 100% of the electricity you use indoors will be converted to heat (with few exceptions like charging batteries) that needs to be removed from the room to be able to live there. 150kW is a lot of power.
        detourdog 2y ago
        I get that. The apartments are small studios created by placing an 11' utility wall that is the kitchen on one side and the bathroom on the other. The kitchen side has 13 129 Volt outlets plus 2 220 volt oven and dryer. I purposely had all those outlets installed as joke to the 150 amps out.
- detourdog 2y ago
  I'm not sure that holds true in a local sense. I have an all electric 8 unit apartment building. I have been tracking the electric usage and it is currently growing but only because of the addition of 2 EVs. I believe the the usage of actual electricity for the building to level off after EVs become the norm. I expect my electric usage to drop after adding a solar thermal collector to replace a portion of the electricity used for heating.
  - closewith 2y ago
    > I expect my electric usage to drop after adding a solar thermal collector to replace a portion of the electricity used for heating. Well, that's just harvesting more solar energy, not reducing your energy needs.
    - detourdog 2y ago
      True. Although it is self-sustaining and doesn't require outside production. I also distinguished between electric usage and thermal collection to satisfy overall energy needs. I guess I'm trying to point out that on an individual level power usage may have a maximum. This might not hold true for commercial ambitions.
      - closewith 2y ago
        I just don't agree. The energy we use today would be seen as absurd even 100 years ago, as will our energy use in the future.
        detourdog 2y ago
        I see the difference between the USA's electric usage today and 100 years ago is that barely anyone had electricity 100 years ago and our standard of living has increased dramatically today. I expect a bump in our usage in the short term due to EV usage but from a household perspective I believe our electric usage will flat line. Heating and cooling are currently the highest usage of power in the domestic setting and large efficiency gains and alternative sources are available. I look at the power usage as a distributed problem and increasing local generation of power will create efficiencies. I also believe that there is finite amount of power that a USA based family of 4 needs. I think the alternate opinions assumes that the power needs are infinite.
- stevenhuang 2y ago
  There's nothing absurd about local generation being able to fulfill/contribute to a large portion of the energy needs of a local residential area. People with residential solar do it all the time with payoff in less than 10 years.
  - closewith 2y ago
    The energy needs of a local residential area will just increase in response to the economically available power, but that's irrelevant as we're talking about agrivoltaics and farms use enormous amounts of energy.
- adrianN 2y ago
  Energy use in the developed world is actually going down. Electricity use is expected to go up in the next decades.
  - closewith 2y ago
    In some parts, due to cost of supply and taxation. Demand for energy is higher than ever.
- lizknope 2y ago
  Do you mean your own personal energy usage? Or your family? City? Country? The world? This is electricity use in the US from 1975 to 2023. Between 2010 to 2023 it has not changed a lot. https://www.statista.com/statistics/201794/us-electricity-consumption-since-1975/ https://www.statista.com/statistics/201794/us-electricity-co... This of course doesn't include things like gasoline or natural gas. My personal energy use has decreased over the last 25 years. Increased insulation and new more efficient HVAC equipment has dropped by summer electric bill by 40%. My old car used to get 26 mpg on the highway and now I get 36. Work from home has dropped my gasoline usage even more. My computer would run 24 hours a day and idle at 180W and now it is 90W.
  - closewith 2y ago
    > Do you mean your own personal energy usage? Or your family? City? Country? The world? All of the above. > This is electricity use in the US from 1975 to 2023. Between 2010 to 2023 it has not changed a lot. Due to the cost of energy ballooning, largely due to taxation. However, the pent up demand is higher than ever.

Rooftop photovoltaic can (and will) cover local needs. Bigger issue is local energy storage (eg. community batteries).

closewith 2y ago

This is absurd. There's no limit to energy needs - they only grow.

IndrekR 2y ago
Sure there are reasonable limits. Where, is another matter. For example, I can not imagine a reasonable use-case for 1MW power-line per single apartment.
- detourdog 2y ago
  I was required to wire each unit with 150kW panel. The original 1931 service was 240 x 200 Amps which I upgraded to 240 x 800 Amps in 2018. I posted the best image I could of the original 1931 schematic which has 9 circuits for 5,000 sqft school. It's the first image in this slide show. https://www.icloud.com/sharedalbum/#B2dGIcgc2GugpW3 https://www.icloud.com/sharedalbum/#B2dGIcgc2GugpW3
  - IndrekR 2y ago
    Interesting. That is like 52 sqm per unit, which is 2.9 kW/sqm — three times higher power density than the solar irradiance on earth surface. If this is used at full power, how are the rooms cooled? (most energy gets converted to heat in typical use-cases)
    - detourdog 2y ago
      I’m not completely following your comment but in 1954 they added a 7,000 sqft addition. We are using mini-splits for HVAC.
      - IndrekR 2y ago
        Almost 100% of the electricity you use indoors will be converted to heat (with few exceptions like charging batteries) that needs to be removed from the room to be able to live there. 150kW is a lot of power.
        detourdog 2y ago
        I get that. The apartments are small studios created by placing an 11' utility wall that is the kitchen on one side and the bathroom on the other. The kitchen side has 13 129 Volt outlets plus 2 220 volt oven and dryer. I purposely had all those outlets installed as joke to the 150 amps out.
detourdog 2y ago
I'm not sure that holds true in a local sense. I have an all electric 8 unit apartment building. I have been tracking the electric usage and it is currently growing but only because of the addition of 2 EVs. I believe the the usage of actual electricity for the building to level off after EVs become the norm. I expect my electric usage to drop after adding a solar thermal collector to replace a portion of the electricity used for heating.
- closewith 2y ago
  > I expect my electric usage to drop after adding a solar thermal collector to replace a portion of the electricity used for heating. Well, that's just harvesting more solar energy, not reducing your energy needs.
  - detourdog 2y ago
    True. Although it is self-sustaining and doesn't require outside production. I also distinguished between electric usage and thermal collection to satisfy overall energy needs. I guess I'm trying to point out that on an individual level power usage may have a maximum. This might not hold true for commercial ambitions.
    - closewith 2y ago
      I just don't agree. The energy we use today would be seen as absurd even 100 years ago, as will our energy use in the future.
      - detourdog 2y ago
        I see the difference between the USA's electric usage today and 100 years ago is that barely anyone had electricity 100 years ago and our standard of living has increased dramatically today. I expect a bump in our usage in the short term due to EV usage but from a household perspective I believe our electric usage will flat line. Heating and cooling are currently the highest usage of power in the domestic setting and large efficiency gains and alternative sources are available. I look at the power usage as a distributed problem and increasing local generation of power will create efficiencies. I also believe that there is finite amount of power that a USA based family of 4 needs. I think the alternate opinions assumes that the power needs are infinite.
stevenhuang 2y ago
There's nothing absurd about local generation being able to fulfill/contribute to a large portion of the energy needs of a local residential area. People with residential solar do it all the time with payoff in less than 10 years.
- closewith 2y ago
  The energy needs of a local residential area will just increase in response to the economically available power, but that's irrelevant as we're talking about agrivoltaics and farms use enormous amounts of energy.
adrianN 2y ago
Energy use in the developed world is actually going down. Electricity use is expected to go up in the next decades.
- closewith 2y ago
  In some parts, due to cost of supply and taxation. Demand for energy is higher than ever.
lizknope 2y ago
Do you mean your own personal energy usage? Or your family? City? Country? The world? This is electricity use in the US from 1975 to 2023. Between 2010 to 2023 it has not changed a lot. https://www.statista.com/statistics/201794/us-electricity-consumption-since-1975/ https://www.statista.com/statistics/201794/us-electricity-co... This of course doesn't include things like gasoline or natural gas. My personal energy use has decreased over the last 25 years. Increased insulation and new more efficient HVAC equipment has dropped by summer electric bill by 40%. My old car used to get 26 mpg on the highway and now I get 36. Work from home has dropped my gasoline usage even more. My computer would run 24 hours a day and idle at 180W and now it is 90W.
- closewith 2y ago
  > Do you mean your own personal energy usage? Or your family? City? Country? The world? All of the above. > This is electricity use in the US from 1975 to 2023. Between 2010 to 2023 it has not changed a lot. Due to the cost of energy ballooning, largely due to taxation. However, the pent up demand is higher than ever.