First U.S. nuclear reactor built from scratch in decades enters commercial operation in Georgia::ATLANTA — A new reactor at a nuclear power plant in Georgia has entered commercial operation, becoming the first new American reactor built from scratch in decades.
If you mean renewables by that, it’s hardly hypothetical or unproven. I’m in Australia and south Australia and Tasmania (two of our states) have fully renewable grids, Tasmania for the past 7 years. South Australia does still occasionally pull from an interconnect but most of the time they’re exporting a bunch of power.
Renewables with storage are cheaper and faster to build than nuclear and that’s from real world costs. Nuclear would be fine if it wasn’t so stupidly expensive.
Generates nearly all its power using hydro electric, which is great but pretty dependent on geography.
Wiki says a pretty big hunk of that is still gas
https://en.wikipedia.org/wiki/Energy_in_South_Australia#/media/File:Electricity_generation_SA_2015-2021.svg
In Ontario Canada where I am from it would take > 4000 wind turbines all working at once (not including the batteries) to supplant our nuclear capacity. Even the largest battery storage are in the hundreds of mega watts and only for a few hours at the cost of about half a billion dollars.
I think it is more productive to approach these technologies as complementary as any proper grid should have both for the near future if we want to reduce global warming.