Read the passage.
Windmill Power
When Malawi, an agricultural country in southern Africa long troubled by poverty, was struck by severe famine in 2002, a widespread lack of electricity and running water hampered its recovery. To lessen his own family's struggles, teenager William Kamkwamba decided to build a windmill to generate power. Others doubted the viability of his idea; Kamkwamba didn't have the finances to buy the proper supplies for such a project. However, Kamkwamba persevered. His first windmill, completed when he was just fourteen, was largely built out of scrap materials—including an old bicycle frame and a tractor fan—and generated enough power for only one light bulb. Kamkwamba then built a stronger windmill, which powered four bulbs. He went on to build several more windmills, including one for pumping water, allowing his family to use electrical appliances and to irrigate their crops. Kamkwamba's success garnered international attention and inspired similar projects.
What is the main, or central, idea of the passage?