Tesla, perhaps to distract from lackluster car sales, just announced plans for battery packs powered by solar panels for residential homes. This is not a new idea. Off-grid homes as well as grid-connected homes with solar panels already have batteries to store energy. So really, why is this news, except that Tesla announced it with great fanfare and says the batteries will look elegant. The amount of hype emanating from Tesla has always made me a bit suspicious.
Working with SolarCity (of which Musk is Chairman) to power the batteries with solar energy just makes the whole endeavor sound like a fantastically Earth-friendly project.
Um, no. Batteries by definition are not earth-friendly at all. They require mining, often in impoverished areas where workers are exploited, use noxious chemicals, and are difficult to dispose of. So don’t go hugging trees quite yet because of the not really green at all Tesla home battery. Is it better than powering your home with coal power? Absolutely. But it’s not green. Batteries probably never can be.
Another problem is the utilities, some of whom are dinosaurs that don’t want to lose revenue because people install solar.
Unregulated batteries to power homes attached to solar panels that keep the battery charged mean some annoyed executives at utilities, especially if the battery’s storage is large enough that it wouldn’t even need much in the way of the electric grid to supplement the solar panels. Not that you’ll ever hear it spelled out so bluntly. Tesla has said that utilities are partners, not enemies, but arguably that just depends on where you look.
Smart utilities, like Green Mountain Energy in Vermont, are leading the move towards home solar. And yes, home batteries do need some regulation. For example, they must never ever send power grid into the grid during a blackout to prevent electric shock to linemen fixing, say, downed power lines, who aren’t expecting power to be coming upstream to them.
Stored power from home solar is a great idea. Let’s hope it becomes ubiquitous soon. For that to happen, the grid will need to be rejiggered to handle distributed energy  flowing from many places to many places rather than the centralized system we have now.