a mix of hydro and non-lithium batteries. for grid scale batteries, you don't care about weight, and if you make it big enough can hear the battery if it helps.

a mix of hydro and non-lithium batteries. for grid scale batteries, you don't care about weight, and if you make it big enough can hear the battery if it helps. as such there are a lot of very cool battery technologies in various stages of commercialization that will never go in a phone, but make a lot of sense when you scale them up to a few thousand pounds.