Nuclear requires a contract to buy all of that energy all of the time - and nobody really does that anymore at nuclear output levels. It’s the reason many large coal plants died of natural causes, nuclear is 2-3x worse

You have a huge upfront cost for building the plant, and then when it is running, relatively little, or very little cost for generating any additional kWh of energy. The funny thing is that when you run an energy market, what determines the market price is the marginal cost, that is, the cost for generating that additional unit! It is the same as when you run a car factory, people are going to give you money for the one car you produce, not for building the factory.

Now, with the marginal cost being near zero, that means that the market price is near zero as well. The price on the energy market goes to near zero. (And this is a very good thing because fossil energy has a much higher marginal cost and is competed out of the market, which is good for our planet's climate).

https://arstechnica.com/science/2019/08/wind-power-prices-no...

With the consequence that both nuclear and renewable need some kind of subsidy or other mechanism which makes sure that the upfront cost is somehow financed.

What's also nice is that much of the subsidy goes in advance. And specifically with renewable power, it is very predictable and can be planned well. You cannot promise, as in so many other areas where government money is spent, that you build it at a cheap price, and then come back and demand more.

And the latter is one reason why big nuclear energy constructors, like Westinghouse, appear to go bust one after another.