Flow batteries, thermal salt storage and simple overcapacity + long-distance transmission are all possibilities. There's an 800 MWh / 200 MW Vanadium flow batt

Flow batteries, thermal salt storage and simple overcapacity + long-distance transmission are all possibilities. There's an 800 MWh / 200 MW Vanadium flow battery being built in Dalian, China, for example. Thermal salt storage is already coupled to thermal solar plants in Spain, but could be run with a heat pump, using any power source. There are actually several promising technologies. It's not as dire as you're suggesting.