Bill Gates, head of charity, is every bit as brilliant and hyperrational as Bill Gates, head of Microsoft, ever was. The cochair of the world’s biggest foundation can hold forth on the impact of polio in India, the challenges of fixing American high schools, and the necessity of distributing better seeds to small farms in Africa. But he really gets amped up about the future of energy. “If you gave me the choice between picking the next 10 presidents or ensuring that ene...