Pumped hydro energy storage is already low specific energy. Compressed air and lifting large masses are even less economical schemes. It may be cheaper to just

Pumped hydro energy storage is already low specific energy. Compressed air and lifting large masses are even less economical schemes. It may be cheaper to just offer time of use pricing to incentivize demand response. EV charging, washing machines, and dishwashers use timers to shift demand to off-peak hours. HVAC and water heaters can be connected via smart grid switches or thermostats. Precooling or preheating can be exploited. During the highest demand days temperatures can be relaxed or units can be duty cycled by splitting customers' units into four groups A B C D and running each for 15 min. to smooth out a soften a sharp spike in total demand.