Geothermal power uses the natural sources of heat inside the Earth to produce heat for distribution and currently; most geothermal power is generated by using steam or hot water from underground. This source of power has been found as a great renewable due to its production of few emissions and is a continuously available power source. In the U.S., there are three geothermal technologies currently in use, which are direct-use systems, use of deep reservoirs to generate electricity, and geothermal heating pumps. The most common is the direct-use geothermal systems, and in these systems, a well is drilled into a geothermal reservoir to provide a steady stream of hot water that is in turn brought up through the well and, by heat exchanger, delivers heat directly to its intended use. This geothermal hot water is used for heating buildings, raising plants in greenhouses, drying crops, heating water for fish farms, or for industrial purposes, at hundreds of sites around the country. The western United States is home to the majority of the geothermal reservoirs appropriate for direct-use systems, specifically those found in California, Hawaii, Nevada, and Utah. Geothermal heat pumps in the U.S. are not only being put to use by hot water, but also by the temperature found beneath the Earth’s surface. It is a fact that underground, the Earth remains at a relatively constant temperature throughout the year, warmer than the air above it during the winter and cooler in the summer. Geothermal heating pumps take advantage of this by transferring heat, stored in the ground, into buildings during the winter, and then transferring it back out into the ground through the summer to keep the energy in a continuous heating cycle with the Earth’s temperature.
Biomass power is power obtained from the energy in plants and plant-derived materials, such as food crops, grassy and woody plants, residues from forestry, and the organic component from industrial wastes. Biomass power is currently the second most important source of renewable energy in the United States behind water. Biomass can be used for direct heating, for generating electricity, or can be converted directly into liquid fuels to meet transportation energy needs. Today, the most common use of biomass energy comes from wood. It has been used longer than any other biomass source and still produces the most energy. The most common use is the burning of wood to produce steam that is used to drive turbines and produce electricity. Another type of biomass energy frequently used is the bio-fuels. Bio-fuels are liquid fuels produced from plants. The two most common in our country today are ethanol and biodiesel. Both ethanol and biodiesel are used for transportation energy needs and used as additives to reduce vehicle emissions or as a renewable alternative fuel for engines. Similar to these types of fuels, another common bio-fuel is rapeseed oil. Rapeseed oil can be used to fuel any vehicle once an adaptation is made to the engine and it is even cleaner than ethanol.