[stymaar]

The power (in W) isn't the relevant value when talking about batteries, it's the stored energy (in Wh) that matters (it's the opposite for dam storage, where energy is plentiful but power is limited). Just do the math and check how many minutes the installation would stay up under significant load from the grid.

BTW I'm baffled to see a website called “energy storage journal” mixing up energy and power like this …