"We could do it for $1 Trillion with liquid-fueled Molten Salt Reactors, on the same amount of land, but with no water cooling, no risk of meltdowns, and the ability to use our stockpiles of nuclear “waste” as a secondary fuel." This is not a production-ready technology, though. I believe there are lingering problems with corrosion. And the claim that the MSR doesn't require secondary water cooling is odd: what's the…
As for water, the working fluid of the heat exchanger and generator can be water, though Helium or CO2 would make more sense.
Additionally, renewables are absolutely not ready to take over base load power generation. They are an incredibly flawed system in their current form, and incredibly expensive (in multiple ways). They can be improved but it'll be a long, long way before we can rely on solar and wind as the core (rather than periphery) of our power generation infrastructure.