Showing posts from May, 2015

Tesla's Powerwall will not piss off your utility company

The headlines over Tesla'a Powerwall have been nothing short of hyperbole: Tesla just made nuclear power obsolete. Elon Musk just seriously pissed off your utility company. Your whole concept of electricity has been turned upside down.

Let's do numbers for a bit. The high-end Powerwall is a 10kWh battery. If you have solar, this is what's meant to keep you going between dusk and dawn. And to illustrate the beauty of this new battery, we see this image of a Powerwall in a garage with a Tesla Model S:

A Tesla! Now let's see. On winter solstice in San Diego, the sun sets at 4:47pm and rises again at 6:48am. So we have over 14 hours without sunlight, i.e. without electricity from solar panels. And that's actually mild - Seattle would be 4:21pm until 7:56am, over 15 1/2 hours!

Tesla's own website says that a single refrigerator takes 1.6kWh per day, so 14 hours would be 1kWh. Since the sun sets early, you'll have lights running for a while. And a TV. Maybe you&#…