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.
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?
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.
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.
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.
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/ 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.
> 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.
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.
