11 ms·

Certainly this is cheaper than paying people to buy your electricity (as sometimes happens in California because of solar plants).

pfdietz 5y ago
Since solar panels can go to zero output onto the grid instantly, this is just a matter of improper design (of the equipment, or of the regulatory regime.) In any case, the cost/kWh from nuclear is computed assuming it's running flat out (except for refueling outages). Reduce that generation and the levelized cost increases. It's already very much higher than renewables; curtailing nuclear output would make that discrepancy worse.
- arcticbull 5y ago
  Sounds like we could solve this problem for for nuclear the same way we look to solve problems for renewables: storage.
  - pfdietz 5y ago
    Except if I have batteries, why should I charge them with expensive nuclear energy when I can charge them with cheap renewables? The nuclear plant will be forced to compete with those renewables for this market, which will limit what it can earn with the otherwise curtailed output. This is not as bad as losing it entirely, or even paying for someone to take it, but it's still going to be a net negative for the plant's economics vs. running all out selling at the calculated cost.
    - seanmcdirmid 5y ago
      Nuclear has very high capital costs but fuel and operating costs (sans financing and insurance) are relatively cheap. Nuclear energy isn’t expensive if the plant is already built, so if you had to choose and the costs were already sunk, it wouldn’t matter. I guess your point is whether to build the plants in the first place rather than going with other renewables. Since hydro is pretty much tapped out, I guess that would be wind or biofuels?
      - ncmncm 5y ago
        Operating cost of nukes is low only compared to coal and oil, and not even to gas. Compared to renewable + storage, nuke operating cost is very, very high.
      - pfdietz 5y ago
        My point was that when you calculate the cost/kWh from a nuclear plant, if you then are going to operate than plant only 50% (say) of the time you could otherwise do so, the cost/kWh from that plant goes way up, because those high fixed costs are now amortized over only half the output. Note that even some of the OPERATING costs of a nuclear plant are fixed. You still need about as many staff to run the plant even if you cycle it up and down. The renewables will be wind and PV. Biomass uses too much land area, and would likely be reserved for specialty markets like chemical feedstocks and perhaps aviation fuel.
        sharkster711 5y ago
        I'd guess a lot of the operating cost of nuclear plants is just the cost to break even - that's repaying infrastructure loans etc
      - throw7576521 5y ago
        > sans financing and insurance if the plant is already built isn’t expensive ?? What renewable isnt given that?
    - mcronce 5y ago
      Do you have sufficient battery capacity to power your grid through a 90th percentile worst case scenario solar outage? 95th? 99th? How long can it go without running coal and gas? Nuclear works when you want it to. Solar and wind work when they want to. That's a very big difference when you're producing the electricity people rely on to live their daily lives.
      - pfdietz 5y ago
        It's a very common mistake to think that batteries are to be used to get to a 100% renewable grid. Hydrogen can be much cheaper for (say) the last 10%, because (1) hydrogen has very low capital cost per unit of storage capacity, and (2) the efficiency hit of going through hydrogen vs. batteries is less important when it's just 10% of the total. Think of batteries and hydrogen as analogous to cache memory and main memory in a computer. They have different performance and economic characteristics and compensate for each others weak points. To see this in operation, go to https://model.energy/ https://model.energy/ and try turning hydrogen off and on in the settings. If you simulate for Germany, for example, turning off hydrogen can double the cost of achieving a certain level of constant grid power. Hydrogen can be particularly valuable for places with large seasonal variation or lots of wind (which has a long timescale component in how it varies.) I will add that China is already selling electrolysers for < $300/kW, less than half that simulation's 2030 cost assumption.
        arcticbull 5y ago
        > Hydrogen can be much cheaper for (say) the last 10%, because (1) hydrogen has very low capital cost per unit of storage capacity, and (2) the efficiency hit of going through hydrogen vs. batteries is less important when it's just 10% of the total. Basically all hydrogen comes from fossil fuels. It's just natural gas with extra steps.
        pfdietz 5y ago
        That's true right now, but that doesn't mean that hydrogen has to come from fossil fuels in the future (any more than most electrical power coming from fossil fuels right now means that that must also be the case in the future.) When describing hydrogen for energy storage in a 100% renewable grid, the hydrogen would be produced by electrolysis using renewable energy.
  - seanmcdirmid 5y ago
    Isn’t that what the EVs could be? There is also pumped storage, but it requires lots of land, water, and elevation differences (the latter I assume being the issue in Finland).
    - pfdietz 5y ago
      Pumped storage needs a lot of water to start but can then just cycle the water between reservoirs. Some will be lost by evaporation, but that loss isn't that high. I once compared a proposed pumped hydro system in Arizona near Phoenix vs. the water evaporated by the Palos Verde nuclear generating station. Per unit of levelized power output, the pumped hydro system used at least an order of magnitude less water than the nuclear plant.
      - ncmncm 5y ago
        That analysis ignores the prospect of siting a solar array floating on the reservoir, with benefits of reduced evaporation and cooler, more efficient conversion, an opportunity unlikely to be long neglected.
        pfdietz 5y ago
        I'm not sure how practical floating solar would be on pumped hydro reservoirs. The water will go up and down a lot.
        ncmncm 5y ago
        It will mostly only go down, anyway, when the sun is not out. If the panels don't mind settling on the banks, or if they are far enough offshore not to, that will not be a problem. It is already common to float panels on regular hydroelectric generation reservoirs, so the event is anyway familiar to operators. If the floats are bottom-heavy and attached to cables spanning the reservoir, the water dropping out from under just leaves them suspended. You need cable attachments, anyway, to extract power and maintain spacing.
- Manuel_D 5y ago
  Granted, the cost for solar and wind fail to account for the cost of storage to accommodate their intermittency. If your country has hydroelectric dams, then that works. But for the rest that don't have the right geography for hydro, they burn fossil fuels. Nuclear provides a path for decarbonization. Solar and wind do not, until a massive breakthrough in energy storage is invented. And nobody knows when that will happen, or if it will happen.
  - rndgermandude 5y ago
    We don't need massive breakthroughs in energy storage. And the goal is overall carbon-neutral, not carbon-zero. And other than wind and solar, we also have hydro and geo-thermal. The latter might become a very important part of the mix, as it would be relatively easy to securely and relatively cheaply deploy a lot of small scale heat pump power plants, requiring fewer massive power line installations, with the added benefit that geo-thermal basically works independent from the time of the day and weather conditions. As for storage, one way to "store" energy is hydrogen, which we can then burn as needed. We can probably get the efficiency of that to 70% (for hydrogen-burning larger-scale power plants). Pumped-storage hydroelectricity is another existing option, with an efficiency of about 70-80%. It's also OK to have some carbon emissions if you can manage to have other measures neutralizing that. We can e.g. use renewable biofuels (e.g. wood, biomass from algae or crops) which "use" a lot of carbon while growing to remove a lot of the emissions the power plants produce, and can with filter technology remove the rest to a degree where we'd still be neutral overall. As I see it, we already got all the basic building blocks, and now it's a matter of optimizing them further and further, and more importantly figuring out the development and deployment (including financing, investment incentives, etc) and logistics (building the additional power lines required is a massive, politically-charged, often NIMBY-kind challenge here in Germany, and from what I hear in a lot of other places including the US too). The deployment and logistics is a general problem of electrification, even with nuclear. People want to plug in their EVs near where they live, and want heat in their homes, so you either need additional power lines or (smaller scale) power plants close to people and industry, either way.
    - lazide 5y ago

pfdietz 5y ago

Since solar panels can go to zero output onto the grid instantly, this is just a matter of improper design (of the equipment, or of the regulatory regime.) In any case, the cost/kWh from nuclear is computed assuming it's running flat out (except for refueling outages). Reduce that generation and the levelized cost increases. It's already very much higher than renewables; curtailing nuclear output would make that discrepancy worse.

arcticbull 5y ago
Sounds like we could solve this problem for for nuclear the same way we look to solve problems for renewables: storage.
- pfdietz 5y ago
  Except if I have batteries, why should I charge them with expensive nuclear energy when I can charge them with cheap renewables? The nuclear plant will be forced to compete with those renewables for this market, which will limit what it can earn with the otherwise curtailed output. This is not as bad as losing it entirely, or even paying for someone to take it, but it's still going to be a net negative for the plant's economics vs. running all out selling at the calculated cost.
  - seanmcdirmid 5y ago
    Nuclear has very high capital costs but fuel and operating costs (sans financing and insurance) are relatively cheap. Nuclear energy isn’t expensive if the plant is already built, so if you had to choose and the costs were already sunk, it wouldn’t matter. I guess your point is whether to build the plants in the first place rather than going with other renewables. Since hydro is pretty much tapped out, I guess that would be wind or biofuels?
    - ncmncm 5y ago
      Operating cost of nukes is low only compared to coal and oil, and not even to gas. Compared to renewable + storage, nuke operating cost is very, very high.
    - pfdietz 5y ago
      My point was that when you calculate the cost/kWh from a nuclear plant, if you then are going to operate than plant only 50% (say) of the time you could otherwise do so, the cost/kWh from that plant goes way up, because those high fixed costs are now amortized over only half the output. Note that even some of the OPERATING costs of a nuclear plant are fixed. You still need about as many staff to run the plant even if you cycle it up and down. The renewables will be wind and PV. Biomass uses too much land area, and would likely be reserved for specialty markets like chemical feedstocks and perhaps aviation fuel.
      - sharkster711 5y ago
        I'd guess a lot of the operating cost of nuclear plants is just the cost to break even - that's repaying infrastructure loans etc
    - throw7576521 5y ago
      > sans financing and insurance if the plant is already built isn’t expensive ?? What renewable isnt given that?
  - mcronce 5y ago
    Do you have sufficient battery capacity to power your grid through a 90th percentile worst case scenario solar outage? 95th? 99th? How long can it go without running coal and gas? Nuclear works when you want it to. Solar and wind work when they want to. That's a very big difference when you're producing the electricity people rely on to live their daily lives.
    - pfdietz 5y ago
      It's a very common mistake to think that batteries are to be used to get to a 100% renewable grid. Hydrogen can be much cheaper for (say) the last 10%, because (1) hydrogen has very low capital cost per unit of storage capacity, and (2) the efficiency hit of going through hydrogen vs. batteries is less important when it's just 10% of the total. Think of batteries and hydrogen as analogous to cache memory and main memory in a computer. They have different performance and economic characteristics and compensate for each others weak points. To see this in operation, go to https://model.energy/ https://model.energy/ and try turning hydrogen off and on in the settings. If you simulate for Germany, for example, turning off hydrogen can double the cost of achieving a certain level of constant grid power. Hydrogen can be particularly valuable for places with large seasonal variation or lots of wind (which has a long timescale component in how it varies.) I will add that China is already selling electrolysers for < $300/kW, less than half that simulation's 2030 cost assumption.
      - arcticbull 5y ago
        > Hydrogen can be much cheaper for (say) the last 10%, because (1) hydrogen has very low capital cost per unit of storage capacity, and (2) the efficiency hit of going through hydrogen vs. batteries is less important when it's just 10% of the total. Basically all hydrogen comes from fossil fuels. It's just natural gas with extra steps.
        pfdietz 5y ago
        That's true right now, but that doesn't mean that hydrogen has to come from fossil fuels in the future (any more than most electrical power coming from fossil fuels right now means that that must also be the case in the future.) When describing hydrogen for energy storage in a 100% renewable grid, the hydrogen would be produced by electrolysis using renewable energy.
- seanmcdirmid 5y ago
  Isn’t that what the EVs could be? There is also pumped storage, but it requires lots of land, water, and elevation differences (the latter I assume being the issue in Finland).
  - pfdietz 5y ago
    Pumped storage needs a lot of water to start but can then just cycle the water between reservoirs. Some will be lost by evaporation, but that loss isn't that high. I once compared a proposed pumped hydro system in Arizona near Phoenix vs. the water evaporated by the Palos Verde nuclear generating station. Per unit of levelized power output, the pumped hydro system used at least an order of magnitude less water than the nuclear plant.
    - ncmncm 5y ago
      That analysis ignores the prospect of siting a solar array floating on the reservoir, with benefits of reduced evaporation and cooler, more efficient conversion, an opportunity unlikely to be long neglected.
      - pfdietz 5y ago
        I'm not sure how practical floating solar would be on pumped hydro reservoirs. The water will go up and down a lot.
        ncmncm 5y ago
        It will mostly only go down, anyway, when the sun is not out. If the panels don't mind settling on the banks, or if they are far enough offshore not to, that will not be a problem. It is already common to float panels on regular hydroelectric generation reservoirs, so the event is anyway familiar to operators. If the floats are bottom-heavy and attached to cables spanning the reservoir, the water dropping out from under just leaves them suspended. You need cable attachments, anyway, to extract power and maintain spacing.
Manuel_D 5y ago
Granted, the cost for solar and wind fail to account for the cost of storage to accommodate their intermittency. If your country has hydroelectric dams, then that works. But for the rest that don't have the right geography for hydro, they burn fossil fuels. Nuclear provides a path for decarbonization. Solar and wind do not, until a massive breakthrough in energy storage is invented. And nobody knows when that will happen, or if it will happen.
- rndgermandude 5y ago
  We don't need massive breakthroughs in energy storage. And the goal is overall carbon-neutral, not carbon-zero. And other than wind and solar, we also have hydro and geo-thermal. The latter might become a very important part of the mix, as it would be relatively easy to securely and relatively cheaply deploy a lot of small scale heat pump power plants, requiring fewer massive power line installations, with the added benefit that geo-thermal basically works independent from the time of the day and weather conditions. As for storage, one way to "store" energy is hydrogen, which we can then burn as needed. We can probably get the efficiency of that to 70% (for hydrogen-burning larger-scale power plants). Pumped-storage hydroelectricity is another existing option, with an efficiency of about 70-80%. It's also OK to have some carbon emissions if you can manage to have other measures neutralizing that. We can e.g. use renewable biofuels (e.g. wood, biomass from algae or crops) which "use" a lot of carbon while growing to remove a lot of the emissions the power plants produce, and can with filter technology remove the rest to a degree where we'd still be neutral overall. As I see it, we already got all the basic building blocks, and now it's a matter of optimizing them further and further, and more importantly figuring out the development and deployment (including financing, investment incentives, etc) and logistics (building the additional power lines required is a massive, politically-charged, often NIMBY-kind challenge here in Germany, and from what I hear in a lot of other places including the US too). The deployment and logistics is a general problem of electrification, even with nuclear. People want to plug in their EVs near where they live, and want heat in their homes, so you either need additional power lines or (smaller scale) power plants close to people and industry, either way.
  - lazide 5y ago