The price of PV cells, once very high, has dropped steadily by half every five years over the last 25 years. As the economics of PV continue to improve, the number installed will increase exponentially. The potential for PV expansion is vast. Solar could provide more power in California than any other source, including natural gas, coal, and nuclear. Geothermal Geothermal energy is generated by converting the hot water or steam from deep beneath the Earth's surface into electricity.
Geothermal plants emit very little air pollution and have minimal impacts on the environment.
They are very economical, competing favorably with fossil fuel generation. Currently, geothermal plants in the U.S. provide enough electricity to supply the homes of 3.5 million people. Known geothermal reserves could supply the entire country with electricity for 30 years, using present-day technology. Biomass 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.