The cacao-farming community of Daban, in Ghana, is seven degrees north of the equator, and it’s always hot. In May, I met with several elders there to talk about the electricity that had come to the town a few months earlier, when an American startup installed a solar microgrid nearby. Daban could now safely store the vaccine for yellow fever; residents could charge their cell phones at home rather than walking to a bigger town to do it. As we talked, one of the old men handed me a small plastic bag of water, the kind street venders sell across West Africa—you just bite off a corner and drink. The water was ice-cold and refreshing, but it took me an embarrassingly long moment to understand the pleasure with which he offered it: cold water was now available in this hot place. There was enough power to run a couple of refrigerators, and so coldness was, for the first time, a possibility.