4 ms·

> In the absence of storage, neither nuclear nor geothermal plants are good at supplying peak demands. This is false. Nuclear and geothermal power can both sat

> In the absence of storage, neither nuclear nor geothermal plants are good at supplying peak demands. This is false. Nuclear and geothermal power can both satisfy peak demand just fine. Nuclear plants do take time to alter the thermal output of the reactor, but they can easily reduce the electric output through overcooling. Same MWt, but lower MWe. Geothermal plants just pump less water into the borehole. Better yet, nuclear plants can direct the excess energy to things like desalination. This is much easier than trying to satisfy peak demand with solar or wind, where peak demand often occurs when the sun isn't visible or when wind speed is substantially higher or lower than demand. Again, France at its peak generated over 85% of it's electricity from nuclear power. I'm not sure where you're getting this myth that nuclear plants can't satisfy variable demand.

philipkglass 6y ago
Nuclear plants can throttle down. But the economics of nuclear power make it prohibitive to satisfy peak demand from nuclear reactors. Even France relies on gas plants and power imports to satisfy its electricity demand peaks, despite being a net electricity exporter over the course of a full year. The CAISO grid had an average power demand of 25 GW in 2019 but a peak demand of 46 GW (Table 1.1): http://www.caiso.com/Documents/2019AnnualReportonMarketIssuesandPerformance.pdf http://www.caiso.com/Documents/2019AnnualReportonMarketIssue... Keeping enough nuclear reactors operating to supply the most demanding hours of the most demanding season would have extraordinarily high marginal costs for the last few terawatt hours.
- Manfredo_1 6y ago
  This is true not because of any shortcomings of nuclear, but by virtue of the fact that demand is not uniform. The same need to have excess capacity during non peak hours in order to have sufficient capacity during peak hours exists with fossil fuels. If peak demand is 130 GW and trough demand is 100GW you need 130 GW of capacity.
  - philipkglass 6y ago
    Nuclear has never been inexpensive enough to be the first choice for meeting peak demand in the absence of storage. Some pumped hydro plants were built in the 20th century to be charged by nuclear generation so nuclear could effectively supply peaks too. Peaking batteries could also be charged by nuclear power. Gas turbines have a construction cost under $1/watt in the US while Vogtle's AP1000s were estimated at $6/watt even before all the cost overruns started. If you're going to leave an asset idle most of the time, much better to idle a sub-$1/watt asset than a $6/watt asset.
    - Manfredo_1 6y ago
      This is just factually wrong. France had generated the majority of it's electricity from nuclear since the 80s, and Belgium now generates the majority of it's power from nuclear. Nuclear had repeatedly been used to satisfy peak demand. Nobody doubts that fossil fuels are cheaper. Yes, that's why fossil fuels are still in widespread use outside of France, and several countries with lots of hydroelectric power. But if we want to halt climate change we need to eliminate - not just reduce - usage of fossil fuels. Any plan to use renewables as a significant source of energy either involves the continued use of fossil fuels, or the involvement of staggering amounts of energy storage.
      - philipkglass 6y ago
        Per the beginning of this long thread, wind and solar can supply 75% of annual US electrical demand without storage. France supplies about that much of its annual demand from nuclear power and Belgium supplies a bit over half of annual demand with nuclear power. Both countries rely on fossil generated electricity for meeting demand peaks, both via domestic generating plants and cross-border imports from foreign fossil plants. There was never a year when France met its peak electrical demand without fossil power. The example of France proves that electrical generation could have been largely decarbonized in the 20th century, if other leaders had made a concerted push to reduce fossil fuel dependency like France's leaders did. It's tragic that other major economies did not do the same. But even France did not eliminate all fossil generation. 10% of French electricity generation is fossil as of 2017 [1]. Getting the USA's electrical generation down to only 10% fossil would be a vast improvement. I don't think that a contemporary optimized plan for getting there involves much new nuclear power even though a 20th century plan would have. A cost optimized plan from 1985 certainly would have called for a lot more nuclear power. The costs of building American solar and wind farms have plummeted since 1985. The costs of building American nuclear plants have not. [1] https://www.world-nuclear.org/information-library/country-profiles/countries-a-f/france.aspx https://www.world-nuclear.org/information-library/country-pr...

philipkglass 6y ago

Nuclear plants can throttle down. But the economics of nuclear power make it prohibitive to satisfy peak demand from nuclear reactors. Even France relies on gas plants and power imports to satisfy its electricity demand peaks, despite being a net electricity exporter over the course of a full year. The CAISO grid had an average power demand of 25 GW in 2019 but a peak demand of 46 GW (Table 1.1): http://www.caiso.com/Documents/2019AnnualReportonMarketIssuesandPerformance.pdf http://www.caiso.com/Documents/2019AnnualReportonMarketIssue... Keeping enough nuclear reactors operating to supply the most demanding hours of the most demanding season would have extraordinarily high marginal costs for the last few terawatt hours.

Manfredo_1 6y ago
This is true not because of any shortcomings of nuclear, but by virtue of the fact that demand is not uniform. The same need to have excess capacity during non peak hours in order to have sufficient capacity during peak hours exists with fossil fuels. If peak demand is 130 GW and trough demand is 100GW you need 130 GW of capacity.
- philipkglass 6y ago
  Nuclear has never been inexpensive enough to be the first choice for meeting peak demand in the absence of storage. Some pumped hydro plants were built in the 20th century to be charged by nuclear generation so nuclear could effectively supply peaks too. Peaking batteries could also be charged by nuclear power. Gas turbines have a construction cost under $1/watt in the US while Vogtle's AP1000s were estimated at $6/watt even before all the cost overruns started. If you're going to leave an asset idle most of the time, much better to idle a sub-$1/watt asset than a $6/watt asset.
  - Manfredo_1 6y ago
    This is just factually wrong. France had generated the majority of it's electricity from nuclear since the 80s, and Belgium now generates the majority of it's power from nuclear. Nuclear had repeatedly been used to satisfy peak demand. Nobody doubts that fossil fuels are cheaper. Yes, that's why fossil fuels are still in widespread use outside of France, and several countries with lots of hydroelectric power. But if we want to halt climate change we need to eliminate - not just reduce - usage of fossil fuels. Any plan to use renewables as a significant source of energy either involves the continued use of fossil fuels, or the involvement of staggering amounts of energy storage.
    - philipkglass 6y ago
      Per the beginning of this long thread, wind and solar can supply 75% of annual US electrical demand without storage. France supplies about that much of its annual demand from nuclear power and Belgium supplies a bit over half of annual demand with nuclear power. Both countries rely on fossil generated electricity for meeting demand peaks, both via domestic generating plants and cross-border imports from foreign fossil plants. There was never a year when France met its peak electrical demand without fossil power. The example of France proves that electrical generation could have been largely decarbonized in the 20th century, if other leaders had made a concerted push to reduce fossil fuel dependency like France's leaders did. It's tragic that other major economies did not do the same. But even France did not eliminate all fossil generation. 10% of French electricity generation is fossil as of 2017 [1]. Getting the USA's electrical generation down to only 10% fossil would be a vast improvement. I don't think that a contemporary optimized plan for getting there involves much new nuclear power even though a 20th century plan would have. A cost optimized plan from 1985 certainly would have called for a lot more nuclear power. The costs of building American solar and wind farms have plummeted since 1985. The costs of building American nuclear plants have not. [1] https://www.world-nuclear.org/information-library/country-profiles/countries-a-f/france.aspx https://www.world-nuclear.org/information-library/country-pr...