The World Bank says annual outages in sub-Saharan Africa can range from 50 hours to 4,600 hours — at the latter end, that’s more than half a year. So an off-the-grid solution is proving valuable in the region and throughout Africa. From Kenya to Tanzania, Uganda to Rwanda, Nigeria to Ivory Coast and even war-torn Somalia, Africans are embracing solar energy solutions that help them power their homes even without being connected to the grid, on an unparalleled scale. Nairobi-based M-KOPA started the revolution. Launched commercially in 2012, M-KOPA allows low-income families access to solar energy for as little as $1 per month. This is cheaper and more environmental than the alternatives, kerosene or diesel fuel, and offers a metered payment system tracked through their phone SIM cards.