So there's always paper reactors that go into variable energy use for industrial chemical applications or water desalination or even carbon capture when the grid doesn't want all the power from a particular power plant. The real solution is over developing nuclear to the point that power is cheap. We could even create artificial fuel instead of drilling for fossil carbons, and use that fuel to retrofit transportation instead of relying on rare earth minerals for batteries. The US Navy actually patented a process to use excess nuclear power at sea to convert seawater to jet fuel. They can't do it enough to not go without a refueling tanker for the inboard fuel tanks, but it's a capacity they can use to extend their fuel reserve a tiny fraction.