Since most energy is used for heat, storing it as heat makes a lot of sense, and there are sand thermal storage systems that can scale from single household to whole neighborhoods.
But then you’re just having another system for storing energy, which probably isn’t very easy to implement. An easier solution if you don’t want to use grid batteries is just to improve housing insulation and schedule heating/cooling for non peak hours, so that you are just using less energy overall. The problem in my mind is that that would require a lot of renovation on older homes, which is just more expensive and slower than adding grid batteries. Don’t get me wrong, those changes should be mandated for newer housing, but expecting it to be implemented in older housing probably isn’t gonna happen.
They’re already using them in Finland. And there’s a company building them for residential applications
If you take something not unlike a water heater and fill it with sand that you then heat to about 1,000 degrees farenheit. Then when you need heat you just pump some air through it and use that feed of hot air to provide heat where you need it. And unlike heat pumps, this can be added to the sort of baseboard heat you find in a lot of older homes.
And since the heaters are just simple resistive coils with 100% efficiency, it’s a simple and cheap way to store electricity that you’re going to use for heating anyway. Remember that every time you change energy from one kind to another you’re going to lose some of it in the process.
