And to add to that, power is almost always the number that is reported/counted so watts is usually correct. That might seem strange since batteries store energy, but in terms of the service they provide to the grid power in/out is more important than storage at least for now.
Edit: 1-2 hours of storage seem to be the current state in Texas at the moment: https://www.renewableenergyworld.com/energy-storage/texas-co...