I recently had two Tesla Powerwalls installed to serve as backup for our home. My Powerwalls are powered by my solar panels which I also expanded since installing in 2015. You can see neat charts such as energy usage, solar production, and battery state. I’ve had energy monitoring for years since I have solar but if this is new to you it’s a bit addicting at first to stare at your power consumption and wonder what is consuming all that power!
I assumed I might go months or years before the Powerwall went into action, but I didn’t have to wait long. The day after my Powerwall was certified, we lost power. A tree fell in our neighborhood and took out power for an estimated 4-6 hours. We had light, we had coffee, our fridge was working and no one in the house really noticed.
PowerWalls make the most sense if you have Solar and live in a state that doesn’t have net metering or charges different rates during the day and at night. In these cases you want energy storage as you can use that stored energy at night or when power rates are more expensive. It’s much easier to justify the cost. I’d invest the money in an electric car first, then solar then a PowerWall if you can afford all that and want all that. PowerWall without Solar is a bad idea as you get no federal tax credit.