Renewable energy comes from natural sources such as sunlight, wind, rain, tides and geothermal heat. These sources are renewable because they are naturally replenished. The document discusses various types of renewable energy sources including solar, wind, hydroelectric, geothermal and biomass. It notes that renewable sources are needed because non-renewable sources like coal and fossil fuels are limited, and burning them causes environmental problems. The conclusion is that renewable energy can help avoid energy disasters by providing sustainable alternatives.