I was looking into getting something like the power walls as a battery backup for power failures, but we ended up going with a generator. We don't have variable power rates here yet for residential, but for a business, those power walls could be a good idea.I don't see any solar panels on their roof (google). So I might guess that they charge these during off peak electrical rates and then use them with their electrical equipment, fork lifts, floor cleaner, etc when needed. I have been to the plant a few times and I do not see much frivolity in Matt's operation. Anyway, he seems to know how to make a business run both smoothly and profitably, while treating his employees well. He also, seems to have a very low employee turn over rate.