* Nuclear energy: Nuclear energy is produced by the fission or fusion of atoms. The heat energy released by nuclear reactions is used to turn a turbine that generates electricity.
* Renewable energy: Renewable energy sources such as solar energy, wind energy, and hydropower can be used to generate electricity. These sources do not produce greenhouse gases and are increasingly being used to meet the world's energy needs.
* Biomass: Biomass is organic matter from plants and animals that can be converted into energy. When biomass is burned, it releases heat energy that can be used to turn a turbine that generates electricity.
