Geothermal energy is a renewable energy source that can be used to offset the use of fossil fuels as well as the emission of greenhouse gases. Geothermal energy was created by the formation of the Earth and is replenished through the radioactive decay of core minerals and the shifting of tectonic plates. The solar rays that constantly strike the earth’s surface also add to the amount of geothermal energy found within the planet.
Geothermal energy is already used by approximately 70 countries across the globe and is capable of supplying 75% to 100% of the commercial energy needed. This would significantly lower the amount of pollution generated.
Despite all these benefits, geothermal energy is not completely pollutant free. The energy plants themselves are capable of releasing pollutants. While the geothermal energy is being extracted, noxious gases and elements are released, such as carbon dioxide, mercury, and sulfur. When released into the atmosphere, these things contribute to acid rain and global warming, things that renewable energy is generally used to lessen. Greenhouse gases are also emitted.
There is a case to be made against geothermal energy because of these extraction emissions. However, while there are pollutants involved with geothermal energy, fewer emissions are released than when fossil fuels are used for energy. If geothermal energy was used in full in place of fossil fuels, it would have a much smaller impact on the environment. These emissions can be offset by injecting any fluids brought to the surface through geothermal energy back into the earth. This is referred to as carbon capture and storage.
Hot water from geothermal sources may contain trace amounts of dangerous elements such as mercury, arsenic, and antimony. If this water is released into rivers or other bodies of water it can be extremely dangerous to humans and animals who may consume the contaminated liquid. Any program to utilize geothermal energy needs to allow for the capture of these elements.
Another aspect to consider is the influence of the geothermal power plants upon the site. Geothermal activity can cause foundational problems with surrounding land, especially if water is used in correlation with a hot dry rock. If the site is overused, or if a plant is larger than the geothermal site’s capacity, it is possible to deplete the area of its geothermal energy. This has a hard impact on the environment, and excess pollution from the remainder of the plant can also cause problems.
Geothermal power plants have minimal land and fresh water requirements compared to other energy sources. Current geothermal plants use 1-8 acres per megawatt (MW) versus 5-10 acres per MW for nuclear operations and 19 acres per MW for coal power plants. They use 20 liters of fresh water per MWh versus over 1,000 liters per MWh for nuclear, coal, or oil.
Geothermal energy has environmental implications to consider. However, when compared to fossil fuels, the impact of geothermal energy on the environment is much smaller relative to its benefits.