This looks exactly like I always imagined battery storage should look like, at least in a first step. Mid-sized batteries strategically distributed in the grid for frequency regulation/grid balancing.
I don't know specifics on this battery farm, but almost all are essentially fleets of shipping containers filled with smaller batteries, rather than some super-cool-mega-battery, so it's probably a safe assumption that this is a landmark project in scale, rather than in technology specifics.