Solar energy is light and heat energy from the sun. Solar cells convert sunlight into electrical energy. Thermal collectors convert sunlight into heat energy. Solar technologies are used in watches, calculators, water pumps, space satellites, for heating water, and supplying clean electricity to the power grid. There is enough solar radiation striking the surface of the earth, to provide all of our energy needs.
Biomass is material of plants and animals that can be used for energy.
Geothermal energy uses heat energy from beneath the surface of the earth.
Fast-flowing water released from dams in mountainous areas can turn water turbines to produce electricity.
Electricity can be obtained by the flow of water through turbines in a dam as the tide rises and falls.
Moving air turns the blades of windmills or generators to make electricity or to pump water out of the ground.