The document discusses and compares different sources of energy, including nuclear energy, natural gas, solar power, wind power, and biomass. It outlines key advantages and disadvantages of each source. Nuclear energy and natural gas are discussed as non-renewable sources that contribute to global warming and have risks of accidents or volatile gases. Solar and wind power are presented as renewable sources but with limitations such as reliance on sunlight or wind. Biomass is described as renewable but potentially expensive and requiring land. Overall wind power is characterized as the "cleanest" source without contributions to global warming.