Starting in 2020, California will become the first U.S. state to require almost all new homes to draw some power from the sun. The solar mandate is part of a wide-ranging push by the world’s fifth-largest economy to combat climate change by weaning itself off fossil fuels.
California already leads the U.S. in home solar panels. Solar makes up about one-seventh of its electricity supply, and that’s expected to grow for the state to meet its goal of 100% carbon-free power by 2045. Others may follow: Massachusetts is weighing a similar mandate, as is Maryland’s Montgomery County. “California has provided the template for a lot of U.S. clean energy policy,” says Hugh Bromley, an analyst for BloombergNEF.