alt Hacker NewsHydro is limited by geography. It cannot scale in the same way. Rather than giant spinning masses at central locations, current thinking is more about smaller masses scattered throughout a grid. There are even a few studies on whether existing air conditioner/heat pump compressors could contribute.
I think geographic dispersion of batteries is going to be a big plus. If the "battery" is a giant lake or a big plant with a spinning mass, the power has to be transmitted from that facility to the end user over the grid
Putting a ton of smaller chemical batteries at distribution substations means when the grid is at the peak, you can cover that peak without transmitting that power over the transmission system. Putting the battery near the consumer will take a big load off of the transmission system which as much of a bottleneck as the lack of generating facilities