Its a bit more complicated then that.

This wasn't always a battery power plant, as its quite an old power plant, this used to be a more contemporary steam based power plant, and it might still be (I forget what the fuel source was, could've been gas, could've been coal, could've been something else feel free to look it up I am not able to at the moment, but point being most of our power generation is literally: how can we boil water efficiently to spin a turbine), and like every contemporary that requires a constant and steady source of water.

Its also very different then farming, a farm isn't in danger of literally self destructing because it went a day without water, but a power plant very well might so it would have to shut down in that event. This has a much more immediate and very drastic effect...because now the neighborhood (or much more, thanks to the joys of grid balancing) just lost power if there was no backup sources to deal with it.