Renewable energy sources are generally being described as environmentally friendly compared to currently dominant fossil fuels and geothermal energy is in this sense no exception. Geothermal energy cannot be described as the perfect energy source from the environmental point of view, but it definitely has much more positive impact on environment than fossil fuels (coal, oil and natural gas) do.
First of all, harnessing geothermal energy does not have the devastating impact on climate change like burning of the fossil fuels does. It is true that fluids drawn from the earth’s core include greenhouse gases such as carbon dioxide and methane, but the amount of released greenhouse gas emissions is negligible compared to those from fossil fuel fired power plants. In fact, the average geothermal plant emit an average of 122 kilograms (270 lb) of CO2 per megawatt-hour of generated electricity, which is tiny amount compared to fossil fuel fired power plants. One of the reasons for this is the fact that geothermal power plants are equipped with emission-control systems that reduce the exhaust. Geothermal power plants emit 97% less acid rain-causing sulfur compounds and about 99% less carbon dioxide than fossil fuel power plants of the same size.
Geothermal fluids contain elevated levels of certain toxic elements such as arsenic, mercury, lithium and boron, which means that geothermal plants need to be equipped with proper waste disposal units in order to ensure that the waste is disposed back into geothermal fields instead of, for instance, ending up in near water bodies where it can create major environmental damage. There have been no reported cases of water contamination from geothermal sites in the United States. Also, most geothermal plants re-inject water into the reservoir after it has been used to prevent contamination and land subsidence.
From the environmental perspective it is also important to mention that geothermal power plants are connected with minimal freshwater and land requirements. This means that geothermal energy commonly has minimal impact on nearby ecosystems.
The only real environmental downside of harnessing geothermal energy is that constructing geothermal plant (which includes deep drilling) can affect land stability, and in some cases even trigger earthquakes (especially enhanced geothermal systems).
Geothermal power plants operate quietly meaning that they do not cause noise pollution. It is often relatively easy to incorporate them into the existing environment without the obvious visual pollution because of their modest land requirements.
It also has to be said that many geothermal sites are located in remote and sensitive ecological areas, so project developers must take this into account when planning geothermal power plants.
To conclude, harnessing geothermal energy with proper care causes negligible damage to environment and is certainly from the environmental perspective one of the best clean energy options. This natural source of energy provides efficient way to harness energy from with minimal impact on its surrounding environment.