Geothermal plants emit very little air pollution and have minimal impacts on the environment.
Organic matter, called biomass, can be burned in an incinerator to produce energy. In newer facilities, the biomass is converted into a combustible gas, allowing for greater efficiency and cleaner performance. Biomass resources include agricultural, forestry, and food processing byproducts, as well as gas emitted from landfills. Dams provide electricity by guiding water down a chute and over a turbine at high speed. Although hydropower does not produce any air emissions, large dams must also consider environmental issues such as flood control, water quality, and fish and wildlife habitat.