In order to answer whether geothermal energy is a renewable and sustainable source of energy it is necessary to characterize terms “renewable” and “sustainable”.
Renewable forms of energy constantly replenish themselves without any human participation. Regardless of how much renewable sources of energy are used their supply will not be exhausted. Examples of renewables include solar energy, hydro-energy and wind energy. The advantage of renewable energy sources is that they can free society of its reliance on non-renewable, finite energy supplies such as oil, coal and natural gas. This is due to the fact that renewable energy sources have both abundant energy flows and the ability for self-regeneration.
The distinguishing feature of sustainable energy sources—besides their renewability—is their capability to sustain the Earth’s ecosystems. By using the sustainable sources of energy the present generations will not jeopardize the ability of future generations to use their sustainable resources to the same amount that those energy sources are currently utilized.
Experts and researchers agree that geothermal energy is a renewable energy resource (U.S. Department of Energy, 2012; DeGunther, 2009; Pierce, 2011) and generation of geothermal energy can be sustained infinitely, as precipitation regularly supplies water to geothermal reservoirs. DeGunther (2009) asserts that geothermal energy is “the only completely renewable energy source from the earth itself” adding that “a well designed geothermal system is perhaps the most environmentally friendly source of energy possible.” According to Dickson and Fanelli (2004), the rate of energy renewal is the most important feature that helps categorize geothermal energy as a renewable energy source. Geothermal energy is a renewable energy source because during the utilization of natural geothermal systems, the rate of production from the resource is equal to the replenishment of thermal water.
While researchers generally concur that the geothermal energy is a renewable energy source, they disagree on the degree on renewability of geothermal energy. According to Tabak (2009), while geothermal energy is a renewable resource, it is not renewable in the same sense that solar energy is renewable. This claim is supported by the fact that an operator of a geothermal power plant must exercise extreme care while monitoring the effects that plant operation has on the geothermal energy supply. If not, the operator runs the risk of permanently ruining the site. That is, geothermal energy technologies must be managed in a way that will not disturb the geothermal resource. Arguably, the degree to which any technological process affects the nature is relative to the intensity of exploitation. Unlike sun and wind, however, geothermal resources are continuously available regardless of weather or climate condition.
Geothermal energy is also a sustainable resource to the greatest extent possible. Coal-fired power plants, for example, emit atmospheric pollutants and greenhouse gases including mercury and carbon dioxide. By contrast, geothermal plants burn nothing and release few greenhouse gases (GHG). These emissions are significantly lower per energy unit than those of fossil fuels. As a result, geothermal energy has the potential to help mitigate global warming if used instead of fossil fuels.
Considerably differing claims are made about the likely role that geothermal energy can occupy in meeting the world’s future energy needs (Tabak, 2009). From one point of view, the global supply of geothermal energy is inexhaustible due to it renewable nature. Other views assert that while a huge supply of geothermal energy does exist, the today’s technology is not advanced enough to access that energy. While both points of view are right, the potential of geothermal energy in meeting the future energy needs will undeniably depend on research and technical advances within the field.
New such advances will significantly extend the size and range of feasible sources, especially for uses such as residential heating. Geothermal energy has been slow to develop in the past, partially due to the price difference between electricity produced by geothermal power plants and coal-fired power plants. It is hoped that this price difference would gradually diminish. If coal were priced more realistically (accounting for environmental externalities, for instance), geothermal power would become more appealing to investors.
To conclude, from the position of environmental sustainability, geothermal energy is an exceptional power source. Renewability, sustainability, and simplicity make geothermal energy especially attractive. Prominently, geothermal energy is superior to fossil fuels including coal, oil and gas because it offers the advantage of putting the society on the sustainable energy path.
Dickson, Mary H., and Fanelli, Mario. What Is Geothermal Energy. Publication. Pisa, Italy: Istituto Di Geoscienze E Georisorse, CNR, 2004.
Energy.gov. US Department of Energy. Available at http://energy.gov.
Geothermal Energy Association. Available at http://www.geo-energy.org.
International Geothermal Association. IGA International Geothermal Association. Available at http://www.geothermal-energy.org.
Pierce, Val. Introduction to Geothermal Power. New Delhi: World Technologies, 2011.
Science News, Articles and Information | Scientific American. Available at http://www.scientificamerican.com.
Union of Concerned Scientists. Available at http://www.ucsusa.org.
Wachtel, Alan and Voege, Debra. Geothermal Energy. New York, NY: Chelsea Clubhouse, 2010.