thats a huge load in the night. Yep, will be interesting what you findThanks everyone. I have to confess I was not reading my bill properly, and the generation charges are the actual SVCE charges, not what credit I am getting. I am not close to being a net exporter. I do get a generation credit during the month, but even off peak I only exceed the what I use a few months in the summer, and I never get close to offsetting peak hour use. The bill is not that easy to understand, but I will dig into it more.
So you are clearly right about the offset of load shifting being a lot smaller than what I was assuming, so the PW's clearly don't pencil out on the load shifting side.
Part of the reason electricity usage is high is I have a couple racks of servers in the basement that I use for a home lab. On average it's about 1800 watts, but it is continuous load - disks spinning, network switches, etc... Still, that's not explaining why in the middle of the night with the lights out I still am burning 5-6 kilowatts every hour. Pool pumps and car chargers shouldn't be running then, so something more investigation is called for.
In any case, the powerwalls clearly don't make sense, but I appreciate all the help I got here! Thanks everyone!