No, GW -- as in the pumped storage facilities can deliver 4 GW of power continuously.

The amount of energy that can be stored in California's pumped storage projects is enormous, measured in hundreds, if not thousands, of GWh, but that's mostly irrelevant to this discussion.

> but that's mostly irrelevant to this discussion.

Is it irrelevant? As another thread mentioned, how long you can provide that power for that for and how fast you can replenish capacity seems relevant for its usefulness buffering solar for after hours.

I'm pretty unread on the energy storage situation so your insight or any good resources are very welcome!

California uses something on the order of 1 GWh/day. If they have the ability to store up hundreds of GWh in a reservoir, then the exact amount becomes largely irrelevant. They have enough, and the limiting factor is power rather than energy.