Renewable Geothermal Resources Team: Ian Zaback Faeldi Zekaj Vikas Tiwari Date: 10/24/2012 Hour: 4th Hour

How The Energy Is Produced Geothermal energy is created by accessing an tapping into the natural heat sources created in the earth. This is done by digging wells and inserting pipes directly into the source of the heat, then piping the heat directly to power plants. The heat energy by then is in the form of steam which is used to power the turbines of electrical generators. Steam is harvested in a variety of ways. -The dry steam method involves pumping steam directly from underground water reservoirs to turbines. -The flash steam method involves relying on already-pressurized reservoirs to provide steam as it rises naturally. -The binary cycle method involves relying on heat from underground reservoirs to boil independently produced organic compounds with a relatively boiling point, thus creating steam. The water is kept separate from the compound and, when cooled, is returned uncontaminated to the earth.

Waste Products When drilling is done to find geothermal sources certain minerals are found to be harmful to ecological communities. These minerals are Hydrogen Sulfide (very corrosive), arsenic, mercury and ammonia. All these minerals are a danger to humans and surrounding ecosystems if precautions are not taken.

Where is it used Places Around the World that Use Geothermal Energy include: Iceland- gets 90 % of its heat for homes and public buildings by directing hot water from the earth into a system of pipes under the streets. Natural hot water is also used in swimming pools, washing machines, and showers. Large greenhouses heated by the earth’s hot water make it possible for Icelanders to grow fruits and vegetables that would otherwise never survive in the bare, cold countryside. California- uses geothermal energy directly in a district-heating program. Similarly, geothermal water warms greenhouses in Idaho, nurtures fish in Utah, and provides hot baths at resorts in Virginia. All around the world renewable geothermal energy is being used more each passing day.

Advantages Readily available as steam from hot water reservoirs with low processing need High versatility; can be used to heat buildings, nurture plants, dry crops, heat water, pasteurize milk and much more. High energy output , capable of potentially generating around 10% of the U.S.’s current electric capability. Creates more local jobs in regions capable of generating geothermal energy. Reduces reliance on fossil fuels Significant amount of money saved; saves 80% of money spent on fossil fuels and requires very low processing fees No pollution- no greenhouse gasses are released, and gasses released are generally not ecologically harmful. These also pose no ecological threat if dealt with carefully.

Disadvantages Low availability of equipment, staff, infrastructure and training Limited geographic reach; the regions that can accommodate harvest of geothermal energy need to have hot rocks underground capable of heating water reservoirs and creating steam. High installation costs (although one time investment) that are pushed up by extensive research needed to investigate the region’s geology and ability to produce sustained steam. Risk of poisonous gasses being released such as Hydrogen Sulfide (very corrosive), arsenic, mercury and ammonia, which are harmful to human health and nearby ecosystems if precautions are not taken.

Interesting Facts Geothermal energy can be found in the form of volcanoes, hot springs and geysers. Geothermal energy has three main uses: Heating, Electricity generation and Geothermal heat pumps. Geothermal energy is used since ancient times in form of hot water. Geothermal energy exploit uses three basic types of geothermal power plants: Dry steam, Flash steam and Binary power plant. Geothermal energy use has such negligible emissions of greenhouse gases such that it can be considered a zero-emission process in this regard. Geothermal energy is extremely efficient (almost 100 %) energy source where only real source of losing energy is from turbine friction. Geothermal energy's advantage is also the fact that geothermal power stations are relatively small, and have a lesser impact on the environment than for instance hydroelectric plants.