Beside the Pan-American Highway, almost 600km (375 miles) north of Santiago, Chile’s capital, lies El Romero, the largest solar-energy plant in Latin America and among the dozen biggest in the world. Its 775,000 grey solar panels spread out across the undulating plateau of the Atacama desert as if they were sheets of water. Built at a cost of $343m by Acciona Energia, a Spanish company, last month El Romero started to be hooked up to the national grid. By April it should reach full strength, generating 196MW of electricity enough to power a city of a million people. A third of its output will be bought directly by Google’s Chilean subsidiary, and the rest fed into the grid.