In the boardroom at Bloom Energy, a single picture hangs on the wall: a satellite image of the world at night. Clusters of bright lights mark the industrial centers, and thin white lines trace connecting passageways such as the U.S. Interstate System and the Trans-Siberian Railroad. In between, huge swaths lie in shadow. Standing almost reverently before the image, K. R. Sridhar, the CEO of Bloom, points to the dark areas—places where electricity isn’t accessible or reliable. “This is my motivation for everything,†he says. To improve the lot of the more than 2 billion people living in those dark...