Pump it to the storage. Building something like https://www.energyvault.com/products/g-vault-gravity-energy-... is impossible for a home owner. But the country scale energy provider can build such thing.

Technically almost all homes have a wonderful energy storage system already -- their hot water heater tank.

One can imagine a setup where you've got a hot water tank and a mixing valve that allows you to heat your water up to some very high temperature and then mix that down to "safe" hot water for the house. Have that run in "heat from grid if below this threshold, otherwise conditionally heat with surplus energy if the water's below this temperature"

Great idea, but that also comes at an additional cost - who would you recommend should pay for that cost?

Storage comes at a cost, but storing cheap/free power offsets even bigger generation costs. So the power company should pay to build storage.

There's a point where the grid has so much solar power that we need to start shedding production as a general rule and not just as an intermittent temporary measure, but I don't think we're anywhere near that point.

Hmmm, run direct carbon capture systems?

Heat up molten salt, or shipping containers full of sand. It’s a surprisingly high density and cheap way to store an awful lot of energy. Don’t have sand batteries here yet, but they’re on my todo for deep storage of excess energy, which I currently just dump as heat into the air.

I don't know. Salt (NaCl) is corrosive. Specific heat capacity is not that high (about 1/5th of water per weight). Suppose you have cubic meter of molten salt at 800°C in a dewar, how do you get the heat out again?