Tesla, it’s been said, is less a car company than a battery company that sells cars. Today, the company is announcing a new milestone: Since 2015, it has installed a worldwide total of a gigawatt-hour of energy storage–technology that is critical for using renewable energy at scale. For comparison, that’s nearly half of the entire amount of energy storage installed globally last year. As the company’s electric car business quickly grows, the energy side of its business is growing even faster.