Wind: Wind power is a good source of energy, but inefficient because you can't always predict the strength of the winds. Wind energy is made by the wind turning a turbine hooked to a generator.

Solar: Solar energy is given off by the sun. It consists of light, heat and other forms of electromagnetic radiation. People have devised many ways to use the sun's energy. Passive solar energy is used for heating. Solar energy can also be used to create electricity with photovoltaic cells.

Hydroelectric: Hydroelectric energy is the best renewable type of energy. All you need is a flowing river and a dam with turbines in it. As the river flows, it turns the turbines to turn a generator. Hydroelectric energy is efficient and nonpolluting.