What is Geothermal?
Geothermal energy is recognized as a renewable resource because it is produced naturally from the heat generated at the Earth’s core. Geothermal power plants offer significant environmental benefits over other methods of generating power. Because the heat is natural, there is no need to combust any fuel, resulting in extremely low emissions. Practically no air emissions or liquids are discharged by binary geothermal plants, which are projected to become the dominant technology in the near future.
| Emission | Nitrogen oxide (NOx) | Sulfur Dioxide (SO2)* | Particulate Matter (PM) | Carbon Dioxide (CO2) |
| Sample Impacts | lung irritation, coughing, smog formation, water quality deterioration | wheezing, chest tightness, respiratory illness, ecosystem damage | asthma, bronchitis, cancer, atmospheric deposition, visibility impairment | global warming produced by carbon dioxide increases sea level, flood risk, glacial melting |
| Geothermal emissions (lb/MWh) | 0 | 0 – 0.35 | 0 | 0 -88.8 |
| Coal emissions (lb/MWh) | 4.31 | 10.39 | 2.23 | 2191 |
| EmissionsOffset by Geothermal Use (per yr) | 32 thousand | 78 thousand tons | 17 thousand tons | 16 million tons |
| Table from “A Guide to Geothermal Energy and the Environment”, prepared for the Geothermal Energy Association by Alyssa Kagel, Diana Bates, & Karl Gawell, updated in April 2007 and available online at http://tinyurl.com/3x5l2cw. | ||||
Geothermal plants have a small surface footprint and visual impact per MW of output even when compared with other renewable energy based power plants, such as any fuel burning plant, or even wind or solar generating facilities.