It happened with computers, cell phones, and now solar panels. Frequently, technologies developed in the U.S. wind up being manufactured in countries with cheaper labor; by the time these products become widely adopted, we’ve ceded the jobs and profits they create. Tesla is determined not to let that happen with lithium-ion batteries, which are expected to play a key role in the transition to green power. With the completion last year of the first phase of its “Gigafactory” in (ahem) Sparks, Nevada, Tesla is about to become a leader in the production of the technology. According to Tesla’s director of global communications, Khobi Brooklyn, by 2020 the Gigafactory will manufacture more lithium-ion batteries annually than were made worldwide in 2013. These batteries, produced in partnership with Panasonic, will be used in Tesla’s electric vehicles—the Model S luxury sedan and Model X SUV, and the forthcoming Model 3 sport sedan—as well as the firm’s Powerwall (home) and Powerpack (business) systems, which can store green power (solar, wind, hydro, geothermal) for a rainy or windless day. (Or for nighttime, when solar panels are as useful as slate tiles.) These systems not only allow customers to extract themselves from the traditional electrical grid but also store energy produced by burning fossil fuels, especially useful during off-peak hours when rates and demand are lower and electricity generated may otherwise go to waste.