> That’s not quite how it works. Yeah in reality there are two forms of hydropower: the classic reservoir dam, and 'run of the river' powerplants. You're absol

> That’s not quite how it works. Yeah in reality there are two forms of hydropower: the classic reservoir dam, and 'run of the river' powerplants. You're absolutely right, even reservoir dams don't really fulfill the 'annual battery' idea, since they must maintain some minimum outflow for downstream consumers and can't shut it off entirely if it better suits the power generation goal.