Small solar panels can transform third world villages.

Many areas of the world are simply off the grid. To bring them electricity, solar is far cheaper than connecting them to the grid or building power plants. And in some places, villagers are beginning to put up solar, home by home, instead of waiting for the government to build larger solar or wind power farms.

Surprisingly, one of the motivating factors is cell phones.

A NY Times article shows a woman in Kenya putting what l...