At the influential TED conference last year, Bill Gates declared that if he were allowed one wish to improve humanity’s lot over the next 50 years, he would choose an “energy miracle”: a new technology that produced energy at half the price of coal with no carbon dioxide emissions. He explained that he’d rather have this wish than a new vaccine or medicine or even choose the next several American presidents. To help understand the reasoning behind Gates’s thinking, one should read Daniel Yergin’s intelligent new opus, “The Quest: Energy, Security, and the Remaking of the Modern World.”