“Goodnight #naturalgas, goodnight #coal, goodnight #nuclear,” Mark Jacobson, an atmospheric scientist at Stanford University in Palo Alto, California, tweeted after news of the deal surfaced late last month. “Because of growing economies of scale, prices for renewables and batteries keep coming down,” adds Jacobson, who has advised countries around the world on how to shift to 100% renewable electricity. As if on cue, last week a major U.S. coal company—West Virginia– based Revelation Energy LLC—filed for bankruptcy, the second in as many weeks. The new solar plus storage effort will be built in Kern County in California by 8minute Solar Energy. The project is expected to create a 400-megawatt solar array, generating roughly 876,000 megawatt hours (MWh) of electricity annually, enough to power more than 65,000 homes during daylight hours. Its 800-MWh battery will store electricity for after the sun sets, reducing the need for natural gas–fired generators. Precipitous price declines have already driven a shift toward renewables backed by battery storage. In March, an analysis of more than 7000 global storage projects by Bloomberg New Energy Finance reported that the cost of utility-scale lithium-ion batteries had fallen by 76% since 2012, and by 35% in just the past 18 months, to $187 per MWh. Another market watch firm, Navigant, predicts a further halving by 2030, to a price well below what 8minute has committed to.