4 ms·

Solar doesn't work at night, so doesn't the cost need to include batteries?

Filligree 2y ago
It does, but battery prices have also been falling precipitously.
epistasis 2y ago
Solar + battery storage is cheaper than nuclear, and also far more flexible. Nuclear, as a baseload generator, is not capable of meeting demand peaks, so if we are going to require batteries for solar, we should require batteries for nuclear as well. Which does not help its case very much.
- AnthonyMouse 2y ago
  > Solar + battery storage is cheaper than nuclear Solar + battery storage is cheaper than Vogtle, but Vogtle was an exercise in mismanagement before COVID caused it to be even worse. Compare: https://www.oecd-nea.org/lcoe/ https://www.oecd-nea.org/lcoe/ > Nuclear, as a baseload generator, is not capable of meeting demand peaks, so if we are going to require batteries for solar, we should require batteries for nuclear as well. Being a baseload generator is what nuclear is used for. It doesn't require batteries because you're not trying to use it for demand peaks. Suppose you have 10GW of demand at night (minimum daily demand), 16GW at midday during peak solar generation and 20GW for two hours right after sunset (maximum daily demand). Do you want 20GW of nuclear? No, you want 10, to handle the first 10GW of demand at all times. That's baseload. Then you want another 10GW of solar, most of which is used directly during midday and the rest of which is used with storage to handle the demand peak just after sunset. Doing it this way means you only need storage for the amount the demand peak after sunset exceeds baseload, which might be 20GWh of storage, instead of needing enough storage to satisfy the entire demand all night, which could be 140GWh. It also improves resistance to low renewable generation because if renewable output is at 50% of normal for a week or more but the grid is half nuclear then the overall grid would have a 25% deficit instead of a 50% deficit. And then you need less in long-term storage, or peaker plants, to pick up that load.
  - bryanlarsen 2y ago
    Using nuclear for base load is silly. Why would you use the 12c/kWh nuclear energy while the sun is shining when you could be using the 0.5c/kWh solar instead?
    - AnthonyMouse 2y ago
      Because you already built the nuclear plant to provide power at night and during periods of low renewable output, and once you're already paying to build and operate it, the incremental cost of also using it during the day is effectively zero and zero is less than any non-zero cost for needing more solar farms. Also, the real numbers aren't actually that far apart because you're using the high end of the estimate range for nuclear and the low end of the range for solar. To replace nuclear with solar for baseload you need the solar farms and batteries for at night and peaker plants for extended periods of low generation during the day and to maintain fueling infrastructure for those peaker plants. You add all of those up and it costs more than using nuclear for baseload.
      - bryanlarsen 2y ago
        No, I'm underestimating the cost for nuclear. During the day, a nuclear plant has to sell power for 0.5 cents / kWh or so. That means that during the night the plant has to sell power for double the price to stay profitable.
  - immibis 2y ago
    I think that commenter is asking: since the nuclear+solar solution requires batteries, why do we account for them as the cost of solar but not as the cost of nuclear? shouldn't it be equal parts both?
    - epistasis 2y ago
      Thank you for clarifying my point, that's exactly what I was trying to say!
    - 2y ago
D-Coder 2y ago
Or some other form of energy storage. If there's a nearby higher-altitude lake, you can pump water uphill. Or you can even just lift blocks of cement or whatever up a tower. Or split water into hydrogen and oxygen and store the hydrogen. Or melt sodium. Etc.

It does, but battery prices have also been falling precipitously.

Solar + battery storage is cheaper than nuclear, and also far more flexible. Nuclear, as a baseload generator, is not capable of meeting demand peaks, so if we are going to require batteries for solar, we should require batteries for nuclear as well. Which does not help its case very much.

AnthonyMouse 2y ago
> Solar + battery storage is cheaper than nuclear Solar + battery storage is cheaper than Vogtle, but Vogtle was an exercise in mismanagement before COVID caused it to be even worse. Compare: https://www.oecd-nea.org/lcoe/ https://www.oecd-nea.org/lcoe/ > Nuclear, as a baseload generator, is not capable of meeting demand peaks, so if we are going to require batteries for solar, we should require batteries for nuclear as well. Being a baseload generator is what nuclear is used for. It doesn't require batteries because you're not trying to use it for demand peaks. Suppose you have 10GW of demand at night (minimum daily demand), 16GW at midday during peak solar generation and 20GW for two hours right after sunset (maximum daily demand). Do you want 20GW of nuclear? No, you want 10, to handle the first 10GW of demand at all times. That's baseload. Then you want another 10GW of solar, most of which is used directly during midday and the rest of which is used with storage to handle the demand peak just after sunset. Doing it this way means you only need storage for the amount the demand peak after sunset exceeds baseload, which might be 20GWh of storage, instead of needing enough storage to satisfy the entire demand all night, which could be 140GWh. It also improves resistance to low renewable generation because if renewable output is at 50% of normal for a week or more but the grid is half nuclear then the overall grid would have a 25% deficit instead of a 50% deficit. And then you need less in long-term storage, or peaker plants, to pick up that load.
- bryanlarsen 2y ago
  Using nuclear for base load is silly. Why would you use the 12c/kWh nuclear energy while the sun is shining when you could be using the 0.5c/kWh solar instead?
  - AnthonyMouse 2y ago
    Because you already built the nuclear plant to provide power at night and during periods of low renewable output, and once you're already paying to build and operate it, the incremental cost of also using it during the day is effectively zero and zero is less than any non-zero cost for needing more solar farms. Also, the real numbers aren't actually that far apart because you're using the high end of the estimate range for nuclear and the low end of the range for solar. To replace nuclear with solar for baseload you need the solar farms and batteries for at night and peaker plants for extended periods of low generation during the day and to maintain fueling infrastructure for those peaker plants. You add all of those up and it costs more than using nuclear for baseload.
    - bryanlarsen 2y ago
      No, I'm underestimating the cost for nuclear. During the day, a nuclear plant has to sell power for 0.5 cents / kWh or so. That means that during the night the plant has to sell power for double the price to stay profitable.
- immibis 2y ago
  I think that commenter is asking: since the nuclear+solar solution requires batteries, why do we account for them as the cost of solar but not as the cost of nuclear? shouldn't it be equal parts both?
  - epistasis 2y ago
    Thank you for clarifying my point, that's exactly what I was trying to say!
  - 2y ago

D-Coder 2y ago

Or some other form of energy storage. If there's a nearby higher-altitude lake, you can pump water uphill. Or you can even just lift blocks of cement or whatever up a tower. Or split water into hydrogen and oxygen and store the hydrogen. Or melt sodium. Etc.