The loss from 1000 Km of transmission is probably comparable to the loss from good case lithium ion (making transmission better much of the time). Pumped hydro

The loss from 1000 Km of transmission is probably comparable to the loss from good case lithium ion (making transmission better much of the time). Pumped hydro is worse than both. Pumped hydro is usually built when it will directly reduce overall grid costs. For example, the Ludington Pumped Storage plant in Michigan was built by utilities to make their generation more cost efficient overall, the energy efficiency of the storage system only needs to be good enough to accomplish that goal.