Andat Datau used to deliver babies by torchlight, but now the nurse, who works in the Nigerian village of Sabon Gida, enjoys constant electricity courtesy of a solar-powered mini-grid. For a country in which 40 percent of the population lives without access to electricity, often relying on expensive and polluting alternatives, these mini-grids have immense potential. A number of African countries, like Kenya, Ethiopia and Zambia have made moves to encourage investment in such systems, which have been made more affordable as solar technology costs come down.