ACCRA, Ghana—My first assignment as a dad this year was to get our infant son electricity. Here in Accra, the power goes out daily, an agony this city shares with tiny villages and teeming metropolises in many parts of Africa.

So I solar-powered our home—less out of environmentalism than exasperation. “I feel like I am going mad slowly,” my wife wrote me recently after another routine daylong outage. “Like Chinese water torture.”

Africa...