I happen to live rather close to a large(?) Amazon fulfillment center they just built a few years ago. Our electricity isn’t very expensive either, though it’s not what hydro areas pay.

I don’t know if we’re a test site or it was just easy to get the power installed or what. Perhaps being a new facility meant they just needed new vehicles anyway so it made sense to not buy gas.

But once they started appearing they kept getting more common.