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> California has a large surplus of renewable energy No they don't. You can see California's energy supply here: https://www.caiso.com/TodaysOutlook/Pages/supp

> California has a large surplus of renewable energy No they don't. You can see California's energy supply here: https://www.caiso.com/TodaysOutlook/Pages/supply.html https://www.caiso.com/TodaysOutlook/Pages/supply.html. Pick a nice sunny day, and you'll see that they're still often using 10+GW of natural gas when renewables peak, and ~5GW of imports from much dirtier neighboring grids. When the sun is down, renewables (including batteries) are often around 10-20% of demand.

Retric 5y ago
It’s not about every day it’s about cool days which lower demand for AC. Look at a long term graph for the spot price of electricity. Also, the grid not designed to move arbitrary power from any producer to any consumer. At times your throttling power from a wind farm while also importing electricity in other areas. The ISO wholesale power market prices electricity based on the cost of generating and delivering it from particular grid locations called nodes. http://www.caiso.com/pricemap/Pages/default.aspx http://www.caiso.com/pricemap/Pages/default.aspx
- burkaman 5y ago
  I understand how the grid works, but I'm not following your argument. > It’s not about every day it’s about cool days which lower demand for AC. There is not a single moment in the history of CAISO when renewables+nuclear was higher than demand. > At times your throttling power from a wind farm while also importing electricity in other areas. Right, so that makes even less likely that abundant wind or solar could make nuclear unprofitable.
  - Retric 5y ago
    > There is not a single moment in the history of Your still thinking of the grid as a uniform entity. There are regular local surpluses with insufficient capacity to move that power to customers. > Right, so that makes even less likely that abundant wind or solar could make nuclear unprofitable. Again depends on location.
    - burkaman 5y ago
      Do you have some evidence that these local surpluses are making nuclear non-viable? Why wouldn't PG&E say that if it were the case? Given the characteristics of the whole grid, they would have to get very unlucky to have so much wind and solar close to the nuclear plant that it was rendered unnecessary. Edit: Also, renewables in California are dominated by solar. Even if there were a local solar surplus during the day, which again I find pretty unlikely, they'd still need nuclear at night. Are you saying the nuclear plant is right next to an incredibly productive wind farm or something?
      - Retric 5y ago
        According to the U.S. Energy Information Administration (EIA), curtailments of solar generation have increased in the California Independent System Operator (CAISO) region. In 2020, CAISO curtailed 1.5 million MWh of utility-scale solar, or 5% of its utility-scale solar production. In other words the grid was unable to accept 5% of all solar power produced in 2020. https://solarenergytea.com/2021/09/08/solar-power-curtailment-continues-to-increase-in-california/ https://solarenergytea.com/2021/09/08/solar-power-curtailmen...
        burkaman 5y ago
        Again, is there any reason to believe this is making nuclear nonviable? Everything you're saying is true, I just don't understand why you think it's connected to the nuclear shutdown. Have you found any articles about nuclear curtailment? Do you think "there is no solar for half the day" is a reasonable point in this discussion? Why wouldn't PG&E brag about the fact that surplus renewables are making nuclear unnecessary if that were true?
        Retric 5y ago
        > making nuclear nonviable? Not nonviable just less viable. This power plant was already scheduled for decommissioning in 2024 so the specifics are only really relevant to it. It’s really constructing a replacement that’s non viable due to the very long time horizons involved. Back in 2018 only 2% of California’s solar was curtailed, by 2040 it might hit 30+%. > about nuclear curtailment? Keeping Nuclear at steady state it useful so it’s the last to be shut off. Frances nuclear was down at 70% capacity factor where US has generally stayed above 90%, but that doesn’t mean US nuclear is profitable every minute it’s operating. Solar curtailment is a sign of very low local spot electricity prices, thus even if your generating electricity during curtailment it’s likely below the average cost of production. > no solar for half the day Environmentally nuclear is a great nighttime source of electricity, but PG&E only care as about the economic question. As to solar, it’s displacing natural gas which can be used at night or on cloudy days. The economic break even point for solar vs natural gas is roughly 50% curtailment so these trends are going to continue. > making nuclear unnecessary It’s not about nuclear being needed or not as current infrastructure is needed as redundancy if nothing else. More generally PG&E is a legal monopoly with a poor reputation not some hip startup that needs publicity. Their simply not going to talk about complex topics most people on HN have trouble understanding let alone the general public.

Retric 5y ago

It’s not about every day it’s about cool days which lower demand for AC. Look at a long term graph for the spot price of electricity. Also, the grid not designed to move arbitrary power from any producer to any consumer. At times your throttling power from a wind farm while also importing electricity in other areas. The ISO wholesale power market prices electricity based on the cost of generating and delivering it from particular grid locations called nodes. http://www.caiso.com/pricemap/Pages/default.aspx http://www.caiso.com/pricemap/Pages/default.aspx

burkaman 5y ago
I understand how the grid works, but I'm not following your argument. > It’s not about every day it’s about cool days which lower demand for AC. There is not a single moment in the history of CAISO when renewables+nuclear was higher than demand. > At times your throttling power from a wind farm while also importing electricity in other areas. Right, so that makes even less likely that abundant wind or solar could make nuclear unprofitable.
- Retric 5y ago
  > There is not a single moment in the history of Your still thinking of the grid as a uniform entity. There are regular local surpluses with insufficient capacity to move that power to customers. > Right, so that makes even less likely that abundant wind or solar could make nuclear unprofitable. Again depends on location.
  - burkaman 5y ago
    Do you have some evidence that these local surpluses are making nuclear non-viable? Why wouldn't PG&E say that if it were the case? Given the characteristics of the whole grid, they would have to get very unlucky to have so much wind and solar close to the nuclear plant that it was rendered unnecessary. Edit: Also, renewables in California are dominated by solar. Even if there were a local solar surplus during the day, which again I find pretty unlikely, they'd still need nuclear at night. Are you saying the nuclear plant is right next to an incredibly productive wind farm or something?
    - Retric 5y ago
      According to the U.S. Energy Information Administration (EIA), curtailments of solar generation have increased in the California Independent System Operator (CAISO) region. In 2020, CAISO curtailed 1.5 million MWh of utility-scale solar, or 5% of its utility-scale solar production. In other words the grid was unable to accept 5% of all solar power produced in 2020. https://solarenergytea.com/2021/09/08/solar-power-curtailment-continues-to-increase-in-california/ https://solarenergytea.com/2021/09/08/solar-power-curtailmen...
      - burkaman 5y ago
        Again, is there any reason to believe this is making nuclear nonviable? Everything you're saying is true, I just don't understand why you think it's connected to the nuclear shutdown. Have you found any articles about nuclear curtailment? Do you think "there is no solar for half the day" is a reasonable point in this discussion? Why wouldn't PG&E brag about the fact that surplus renewables are making nuclear unnecessary if that were true?
        Retric 5y ago
        > making nuclear nonviable? Not nonviable just less viable. This power plant was already scheduled for decommissioning in 2024 so the specifics are only really relevant to it. It’s really constructing a replacement that’s non viable due to the very long time horizons involved. Back in 2018 only 2% of California’s solar was curtailed, by 2040 it might hit 30+%. > about nuclear curtailment? Keeping Nuclear at steady state it useful so it’s the last to be shut off. Frances nuclear was down at 70% capacity factor where US has generally stayed above 90%, but that doesn’t mean US nuclear is profitable every minute it’s operating. Solar curtailment is a sign of very low local spot electricity prices, thus even if your generating electricity during curtailment it’s likely below the average cost of production. > no solar for half the day Environmentally nuclear is a great nighttime source of electricity, but PG&E only care as about the economic question. As to solar, it’s displacing natural gas which can be used at night or on cloudy days. The economic break even point for solar vs natural gas is roughly 50% curtailment so these trends are going to continue. > making nuclear unnecessary It’s not about nuclear being needed or not as current infrastructure is needed as redundancy if nothing else. More generally PG&E is a legal monopoly with a poor reputation not some hip startup that needs publicity. Their simply not going to talk about complex topics most people on HN have trouble understanding let alone the general public.