In sunny California, solar panels are everywhere. They sit in dry, desert landscapes in the Central Valley and are scattered over rooftops in Los Angeles’s urban center. By last count, the state had nearly 47 gigawatts of solar power installed — enough to power 13.9 million homes and provide over a quarter of the Golden State’s electricity. But now, the state and its grid operator are grappling with a strange reality: There is so much solar on the grid that, on sunny spring days when there’s not as much demand, electricity prices go negative. Gigawatts of solar are “curtailed” — essentially, thrown away.