In the near future, the sun will come closer to you—so will the wind take up residence nearby. In a friendly neighbourhood battery, that is. The lithium-ion battery that runs your smartphone today could soon power Indian homes, cars and offices alike. This isn’t the stuff of science fiction, but a reality in the making. It already is a reality, for a small percentage of homes in countries such as the US and Germany. The scenario is doubly tempting: one, because of the vastly improved ways in which the Indian sun will soon be harvested; and two, because of how the big push towards renewable energy is accompanied by a technological leap in batteries—how they can trap, store and deliver power.