William Kamkwamba and harnessing the wind

At age 14, in poverty and famine, a Malawian boy built a windmill to power his family’s home. At 22, William Kamkwanba, who speaks at TED, here, for the second time, shares in his own words the moving tale of invention that changed his life.

To power his family’s home, young William Kamkwanba built an electricity-producing windmill from spare parts and scrap — starting him on a surprising journey detailed in the new book, “The Boy Who Harnessed the Wind.”