Google will buy 536 megawatts of wind power, adding to the company’s already large supply, making it the biggest corporate purchaser of renewable energy, according to a statement Thursday. The Alphabet subsidiary will purchase wind energy from four different power plants: two in South Dakota, one in Iowa and one in Oklahoma. Google announced at the end of last year that it would reach 100% renewable energy in 2017. With these deals, the company has agreed to buy enough power to compensate for all of its energy needs this year, though some of the projects are not yet operational.