In a similar way we will eventually have nuclear powered aircraft and cargo ships. Power and heat from nuclear plants on land will be used to manufacture synthetic liquid fuels.
I think nuclear powered should be used to something that has a nuclear reactor on board directly supplying power.
> start and stop intermittently
Solar & wind electricity is actually fairly predictable, based on the weather forecast. You don't know what it's going to be next week, but you do have a good idea what it's going to be in an hour. That helps a lot.
> fixed delivery commitments to customers
Maybe in the future, but that's definitely not an issue at the moment because excess production can always be sold without the green premium.