Spent about forty minutes last night doing math on the back of an envelope about whether I could ever justify a Tesla Powerwall, which is a ridiculous thing to do at 11pm on a Monday but here we are. Musk unveiled the thing at that event in Hawthorne a couple weeks back — the 10 kWh version for weekly cycling runs $3,500, and there's a 7 kWh daily-cycle one for $3,000, before you even get to the inverter and installation costs, which nobody was talking about on stage but which I guarantee eat a huge chunk of that number in practice. Still. A wall-mounted battery that quietly banks your solar (or off-peak grid power, if you're not one of the six people in America with rooftop panels) and hands it back to you during peak hours is a genuinely interesting idea, and I don't say that about most keynote reveals.
Except I rent. I've got a one-bedroom on the third floor with a landlord who takes eleven days to fix a leaking faucet, and there is exactly zero chance he's letting me bolt a battery pack to a wall he owns so I can save forty bucks a month on my electric bill. This is the part nobody in the excited tech coverage seems to want to sit with — Powerwall is a fantastic pitch if you own a house, have a garage or exterior wall to spare, and live somewhere with time-of-use electricity rates that actually make the payback math work. For the rest of us it's basically a very elegant piece of furniture we'll read about. I'm not being bitter about it, or maybe I am a little. I just think a lot of the "this changes everything" framing going around skips over the fact that most people who'd want one can't actually get one installed.
What I keep coming back to is that the interesting part isn't really the box on your wall, its the fact that a car company decided the more durable business is stationary storage, not the cars. That's the bet, quietly, underneath the announcement. Whether it pays off is a different question and not one I'm going to pretend to answer from my kitchen table.
Anyway. Unrelated but sort of related tangent: I went to see Age of Ultron opening weekend, packed theater, sold-out 9:40 showing, and sat there thinking about how funny it is that the villain of the biggest movie of the year so far is basically a rogue AI that got created by well-meaning engineers who didn't think hard enough about what they were building. Every few years Hollywood does this and every few years I read a dozen thinkpieces about "what Ultron gets wrong about AI" and honestly I don't care that much whether the science is right, I just think its funny that we keep telling ourselves the same cautionary story about smart people building something they lose control of, and it keeps making a few hundred million dollars, and none of us change our behavior even slightly. James Spader's voice work was the best part by a mile, for what its worth. Didn't love the movie as much as the first one but that's a whole separate post I'm not writing tonight.
Back to batteries for a second because I can't let it go: I did the math three different ways and at my current usage, a Powerwall would take somewhere north of nine years to pay for itself even under generous assumptions, and that's before accounting for the fact that lithium-ion packs degrade and I'd probably need to replace the thing before it broke even. Which doesn't make it a bad product. It just means the "revolution" is a few price cuts and a few years away for anyone who isn't already living somewhere with high electricity rates and a house they own outright. I'll be here, renting, watching from the sidelines, occasionally doing envelope math at 11pm for no reason other than I find the whole category genuinely interesting even when it doesn't apply to my life yet.
Going to go stare at my breaker box now like that'll tell me something useful. It won't.