Expanding from cars to homes makes sense for Tesla Motors. Storing energy is a huge piece of the electric car puzzle. In order to run smoothly, an electric car has to have a battery that is durable, long-lasting, and efficient. As Klint Finley at Wired notes, those same qualities are incredibly important for renewable energy expansion too. If a home or business wants to switch from the grid to a renewable power source like solar panels, a big part of making that change attractive is the ability to save up some electricity for a rainy (or cloudy) day. Having a huge battery ready to store extra juice could make moving to renewables much easier.