By Josh Dzieza
Earlier this week, during a disappointing Tesla earnings call, Elon Musk mentioned in passing that he’d be producing a stationary battery for powering the home in the next few months. It sounded like a throwaway side project from someone who’s never seen a side project he doesn’t like. But it’s a very smart move, and one that’s more central to Musk’s ambitions than it might seem.
To understand why, it helps to look not at Tesla, but at SolarCity, a company chaired by Musk and run by his cousin Lyndon Rive. SolarCity installs panels on people’s roofs, leases them for less than they’d be paying in energy bills, and sells surplus energy back to the local utility. It’s proven a tremendously successful model. Founded in 2006, the company now has 168,000 customers and controls 39 percent of the rapidly expanding residential solar market.
Fueled by financing systems like SolarCity’s, government subsidies, and a rapid drop in the price of photovoltaics, solar has been growing fast. But with that growth, some of solar’s downsides are coming to the fore. Obviously, the sun isn’t always shining when you need power, and sometimes the sun is shining when you don’t need power. The former is a problem for the user, who needs to draw on the grid when it’s cloudy or dark; the latter is a problem for the grid, which needs to find a place for that excess energy to go. When there’s a lot of solar in the system, it can get hard to keep the grid balanced.
That’s part of the reason that California, with one of the most aggressive renewable energy mandates in the country, recently declared the most aggressive energy storage mandate as well, with a goal of 1.3 gigawatts of storage by 2020. As other states adopt intermittent renewables like solar and wind, they’ll need to install energy storage too, providing a ready and waiting market for Tesla’s batteries.