Energy storage solutions are getting better, but energy storage research didn't really pickup till the 1990s.
Pumped Hydro (~80% efficiency) is still the best large-scale energy storage mechanism in the USA. Maybe in a few years Redox-Flow Batteries (Or flywheels, or Lithium, or Compressed Air, or...) will catch up to technologies from the 1960s and we can have advanced energy storage.
But for now, the vast vast majority of energy storage is basically pumping water up a hill and letting it back down at a later time. Something like 95% of the entire USA's energy storage is pumped hydro.
Pumped Hydro (~80% efficiency) is still the best large-scale energy storage mechanism in the USA. Maybe in a few years Redox-Flow Batteries (Or flywheels, or Lithium, or Compressed Air, or...) will catch up to technologies from the 1960s and we can have advanced energy storage.
But for now, the vast vast majority of energy storage is basically pumping water up a hill and letting it back down at a later time. Something like 95% of the entire USA's energy storage is pumped hydro.