> Put differently, in 2019 Fessenheim Unit 1 and 2 generated more electricity than all the solar panels in France combined
I learned a term recently called "base load supply". Essentially, something like a nuclear plant is hard to ramp/up down with changing grid demands, but it great at steady-state operation and can run like that for years. This takes care of the minimum load placed on the grid which is fairly predictable.
Nuclear strengths' play an important role in an "all of the above" approach.
Renewables and nuclear -both- have the problem that you can't control when you get the generation.
Nuclear wants to be constant-- both because ramping isn't super fast and because you want to recover large capital costs. Renewables ... produce varying amounts pseudo-periodically and unpredictably, which is even worse. Neither matches conventionally to demand.
The only way around this is technologies that store (hydroelectric, batteries, power-to-gas-to-power, solar thermal) or burning fossil fuels to supplement. Overprovisioning is also necessary: it takes a lot less storage / peaker plants / etc to meet 99th percentile demand with 150% of required generation capacity than 101%.
Renewables and nuclear do complement each other a little bit in reducing volatility.
If I'm not mistaken nuclear in France is actually pilotable quite fast, it is not instantaneous but it is really fast. You cover the risk of shortest term high variance with other means, but they basically already exist (hydro, gaz) and you don't need much.
This is not necessarily the case for all nuclear power plant, it has to be designed for that.
It depends what you call fast. It's my understanding that PWR's like this ramp from 50% to 90% in about an hour.
But nuclear power plants have a huge capital cost, so you really don't want them to operate for half of the day at 40% or they're even more expensive for the power generated.
And going below a minimum output power means a long time to get power back, which is why in North America power prices sometimes go negative (don't want to shut down).
But it isn't really financially optimal to do that. The marginal cost of an extra MWh is trivial. The staff and capital costs are going to be mostly the same regardless of output. So it makes sense to run it as much as possible. In that sense it is very similar to solar and wind. In comparison a gas plant is spending a lot of money on fuel and will shut down to save money as prices drop.
Also, the grid needs much faster reaction than modulating demand over hours. If a large generator fails (which sometimes happens to nuclear plants) you need 1GW in a few seconds.
I learned a term recently called "base load supply". Essentially, something like a nuclear plant is hard to ramp/up down with changing grid demands, but it great at steady-state operation and can run like that for years. This takes care of the minimum load placed on the grid which is fairly predictable.
Nuclear strengths' play an important role in an "all of the above" approach.