Smartphones have been adopted by the billions worldwide in no small part because they are wireless. But they're not entirely so. They still use wires to draw electricity -- whether from a coal-fired power plant hundreds of miles away or a rooftop solar panel.
While delivering the next billion smartphones to first-time customers is relatively easy, finding ways to charge them is not, because many people in developing countries lack reliable access to electricity. Solving this problem will challenge the rich world’s assumptions about what services should be provided by which kinds of network companies.