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Given the dramatically lower costs of utility-scale solar vs. residential rooftop solar, is it not better at a society level for state policy to incentivize uti

Given the dramatically lower costs of utility-scale solar vs. residential rooftop solar, is it not better at a society level for state policy to incentivize utility over residential solar? Utility-scale battery installations likewise should be much cheaper.

ghaff 3y ago
Residential solar may still make sense for new construction (maybe?) in the right areas. But there was a lot of scammy behavior around home solar installation at one point. Given that home solar does not effectively give you a backup generator for free (barring a lot of batteries and specific electrical hookups as I recall), it's not clear it's a big win in general. A lot of utility things aren't ideal at the individual house level if there's an option.
- mbgerring 3y ago
  A lot of home solar installers now include grid tied batteries as part of a standard installation, which is what NEM 3 was intended to do (secondarily, after its primary goal of giving CA IOUs a massive free lunch).
epistasis 3y ago
This argument ignores the cost of transmission and distribution, which are higher costs than the generation itself. And as electricity prices are driven down even further, T&D will come to dominate over energy generation costs. Few models account for this, but Christopher Clack made one, and the lowest cost energy path was a small amount of investment in distribution now, paired with massive deployment of solar on homes and industrial/commercial. This won't happen unless utilities are forced into it or their allowed profit model is changed to deliver ratepayers the lowest cost energy, however.
- LUmBULtERA 3y ago
  Unless every home is completely off the grid, you’re going to need to pay for most or the majority of that transmission and distribution anyway. Peak winter and summer I also would imagine many or most residential deployments aren’t going to cover their own need, unless they’re incredibly over built with massive batteries. In any case, I should check out your Christopher Clack reference.
  - nerdbert 3y ago
    You don't need as much grid capacity if houses have their own generation and storage.
    - kalleboo 3y ago
      The grid still needs to be built for the worst case - houses aren't going to have days of storage for a week of cold weather with dark clouds
      - fragmede 3y ago
        Worst case is months. In the depths of winter you need energy captured from the sun during summer. That's a drastic rethinking of the scale of storage.
        kalleboo 3y ago
        Absolutely. For the sake of the topic of discussion I was trying to think of Californian conditions but for places like Sweden you'll need completely different solutions (Sweden has been powered 100% on Hydro+Nuclear for decades now so that's one way)
  - epistasis 3y ago
    The modeling is a few years old now, but here's a podcast episode diving into details: https://xenetwork.org/ets/episodes/episode-146-why-local-solar-costs-less/ https://xenetwork.org/ets/episodes/episode-146-why-local-sol... (And of course, perhaps one modeler can get it wrong. But over here in California where the majority of our sky high electricity cost is from T&D, it definitet feels very true. And last national stats I saw had T&D as higher than generation costs)
  - _aavaa_ 3y ago
    As long as the houses are still connected to the grid you will indeed by paying for distribution costs. But I think that you should expect to see transmission savings since you'll have more of the demand met locally.
- harryseldon 3y ago
  My PG&E bill would make you think so. But that is a PG&E problem (well problem for the consumer and great for their bottom line). Generation is the majority of the cost across the US: https://www.eia.gov/energyexplained/electricity/prices-and-factors-affecting-prices.php https://www.eia.gov/energyexplained/electricity/prices-and-f...
- fbdab103 3y ago
  Wouldn't that mean further subsidizing rich homeowners? The people best positioned to take advantage of incentives own their own home and have the disposable cash to make the initial outlay for residential generation.
  - ketzo 3y ago
    Yep, it definitely would. It doesn't mean we shouldn't still do it -- especially because richer folks tend to use more electricity and pollute more in general.
conradev 3y ago
Generally, yes, but a few items: - Distribution systems today can only handle some percentage of EV penetration in a given area, not 100%. Charging an EV from the roof skips the grid entirely - The bulk of the cost is labor and permitting, not the modules themselves. Given that, California requires solar on newly constructed homes - California updated their net metering program so that ratepayers aren’t subsidizing rooftop solar anymore (in NEM 3.0, homeowners get paid wholesale rates)
- inglor_cz 3y ago
  "Charging an EV from the roof skips the grid entirely" As long as you have enough sunshine hours in your region. Southern Spain is fine year-round, but you won't get any meaningful output out of a solar panel in Finnish winter. The rest of Europe lies between those two extremes. Northern winter will be made more challenging by addition of EVs to the grid, because a lot of electricity is being used for heating as well.
photochemsyn 3y ago
As far as rooftop solar, it makes a big difference if solar PV is built into the design process at the beginning, rather than tacked on as an afterthought. Similarly, a household battery might be as common in the future as a household hot water heater (with a similar footprint, size-wise). There's also regional variability - cities absolutely require utility-scale solar, just as they require dedicated agricultural land to feed the population, because there's not enough surface area in a city. Rural/suburban areas on the other hand are ideal for integrated rooftop solar.
rstuart4133 3y ago
> Given the dramatically lower costs of utility-scale solar vs. residential rooftop solar According to Wikipedia the LCOE on small roof top solar is about twice that of utility solar. [0] So yes, it's dramatically better. But typically the price difference between what the utility is paid and what the customer is charged is 3 times, so your average household is better off installing solar despite generating it at twice the cost of a utility. The price difference isn't just transmission costs. It's also retail markup, regulatory charges and metering and billing. [0] https://en.m.wikipedia.org/wiki/Cost_of_electricity_by_source https://en.m.wikipedia.org/wiki/Cost_of_electricity_by_sourc... - there are a lot of tables in that page. Twice looks to be generous to the utilities.

ghaff 3y ago

Residential solar may still make sense for new construction (maybe?) in the right areas. But there was a lot of scammy behavior around home solar installation at one point. Given that home solar does not effectively give you a backup generator for free (barring a lot of batteries and specific electrical hookups as I recall), it's not clear it's a big win in general. A lot of utility things aren't ideal at the individual house level if there's an option.

mbgerring 3y ago
A lot of home solar installers now include grid tied batteries as part of a standard installation, which is what NEM 3 was intended to do (secondarily, after its primary goal of giving CA IOUs a massive free lunch).

epistasis 3y ago

This argument ignores the cost of transmission and distribution, which are higher costs than the generation itself. And as electricity prices are driven down even further, T&D will come to dominate over energy generation costs. Few models account for this, but Christopher Clack made one, and the lowest cost energy path was a small amount of investment in distribution now, paired with massive deployment of solar on homes and industrial/commercial. This won't happen unless utilities are forced into it or their allowed profit model is changed to deliver ratepayers the lowest cost energy, however.

LUmBULtERA 3y ago
Unless every home is completely off the grid, you’re going to need to pay for most or the majority of that transmission and distribution anyway. Peak winter and summer I also would imagine many or most residential deployments aren’t going to cover their own need, unless they’re incredibly over built with massive batteries. In any case, I should check out your Christopher Clack reference.
- nerdbert 3y ago
  You don't need as much grid capacity if houses have their own generation and storage.
  - kalleboo 3y ago
    The grid still needs to be built for the worst case - houses aren't going to have days of storage for a week of cold weather with dark clouds
    - fragmede 3y ago
      Worst case is months. In the depths of winter you need energy captured from the sun during summer. That's a drastic rethinking of the scale of storage.
      - kalleboo 3y ago
        Absolutely. For the sake of the topic of discussion I was trying to think of Californian conditions but for places like Sweden you'll need completely different solutions (Sweden has been powered 100% on Hydro+Nuclear for decades now so that's one way)
- epistasis 3y ago
  The modeling is a few years old now, but here's a podcast episode diving into details: https://xenetwork.org/ets/episodes/episode-146-why-local-solar-costs-less/ https://xenetwork.org/ets/episodes/episode-146-why-local-sol... (And of course, perhaps one modeler can get it wrong. But over here in California where the majority of our sky high electricity cost is from T&D, it definitet feels very true. And last national stats I saw had T&D as higher than generation costs)
- _aavaa_ 3y ago
  As long as the houses are still connected to the grid you will indeed by paying for distribution costs. But I think that you should expect to see transmission savings since you'll have more of the demand met locally.
harryseldon 3y ago
My PG&E bill would make you think so. But that is a PG&E problem (well problem for the consumer and great for their bottom line). Generation is the majority of the cost across the US: https://www.eia.gov/energyexplained/electricity/prices-and-factors-affecting-prices.php https://www.eia.gov/energyexplained/electricity/prices-and-f...
fbdab103 3y ago
Wouldn't that mean further subsidizing rich homeowners? The people best positioned to take advantage of incentives own their own home and have the disposable cash to make the initial outlay for residential generation.
- ketzo 3y ago
  Yep, it definitely would. It doesn't mean we shouldn't still do it -- especially because richer folks tend to use more electricity and pollute more in general.

conradev 3y ago

Generally, yes, but a few items: - Distribution systems today can only handle some percentage of EV penetration in a given area, not 100%. Charging an EV from the roof skips the grid entirely - The bulk of the cost is labor and permitting, not the modules themselves. Given that, California requires solar on newly constructed homes - California updated their net metering program so that ratepayers aren’t subsidizing rooftop solar anymore (in NEM 3.0, homeowners get paid wholesale rates)

inglor_cz 3y ago
"Charging an EV from the roof skips the grid entirely" As long as you have enough sunshine hours in your region. Southern Spain is fine year-round, but you won't get any meaningful output out of a solar panel in Finnish winter. The rest of Europe lies between those two extremes. Northern winter will be made more challenging by addition of EVs to the grid, because a lot of electricity is being used for heating as well.

photochemsyn 3y ago

As far as rooftop solar, it makes a big difference if solar PV is built into the design process at the beginning, rather than tacked on as an afterthought. Similarly, a household battery might be as common in the future as a household hot water heater (with a similar footprint, size-wise). There's also regional variability - cities absolutely require utility-scale solar, just as they require dedicated agricultural land to feed the population, because there's not enough surface area in a city. Rural/suburban areas on the other hand are ideal for integrated rooftop solar.

rstuart4133 3y ago

> Given the dramatically lower costs of utility-scale solar vs. residential rooftop solar According to Wikipedia the LCOE on small roof top solar is about twice that of utility solar. [0] So yes, it's dramatically better. But typically the price difference between what the utility is paid and what the customer is charged is 3 times, so your average household is better off installing solar despite generating it at twice the cost of a utility. The price difference isn't just transmission costs. It's also retail markup, regulatory charges and metering and billing. [0] https://en.m.wikipedia.org/wiki/Cost_of_electricity_by_source https://en.m.wikipedia.org/wiki/Cost_of_electricity_by_sourc... - there are a lot of tables in that page. Twice looks to be generous to the utilities.