How Geothermal Energy is used
Introduction/Thesis
At the beginning of this century, the term “alternative energy” has become a keyword in describing new energy sources without the use of fossil fuels. Recently both developed and developing countries are looking for cleaner and more efficient ways to use energy for a variety of reasons. Geothermal energy is an alternative source of energy that many countries such as the United States and New Zealand are starting to tap into. Geothermal energy is a source of energy in which internal heat from the planet can be used to generate steam through a steam turbine. This could be used on a small scale by providing heat to a residential unit, but also on a much larger scale by supplying energy production through a geothermal power plant. There are many issues associated with geothermal energy such as reliability, cost, availability, aesthetics, and sustainability. All of these come into play when studying the use of geothermal energy, but one of the most important and controversial issues is whether geothermal energy is friendly for the environment.
Geothermal Energy uses
Geothermal energy has been used commercially for about one century and its large-scale utilization started around 40 years ago. This was used for both electricity generations in developing countries, as well as direct application for space heating. There is a wide variety of geothermal energy uses, depending on the need of the resource. Geothermal energy can be used for district heating, space heating, industrial processes, desalination applications, and agricultural applications. Most developed or developing countries are using geothermal energy through power plants to generate electricity. (Geothermal energy systems, 1). The production of electricity from geothermal energy sources can be very powerful and effective, but the location is key when tapping into geothermal resources. There are only a handful of places around the world that can produce effective and viable levels of electricity from geothermal energy sources.
Issues associated with geothermal energy use
Like every energy source, geothermal energy utilization has a number of issues associated with it. There are six main areas worth discussing in accordance to geothermal energy. There is reliability, cost, availability, aesthetics, sustainability, and environmental friendliness.
Reliability
In terms of reliability, geothermal plants are possibly the most dependable of all energy production methods. They tend to be simpler than most other power systems, which means less can go wrong. The plants require no purchase of fuel, and they require no waste disposal. It’s also important to note every geothermal energy facility that has been built in the last 100 years is still in production. (Energy Consumers Edge, 1).
Cost
When it comes to the cost, geothermal plants are very competitive in geologically suitable areas. Geothermal power plants do have high initial costs to construct and drill new facilities, but those costs are equalized due to no fuel costs. Geothermal plants are currently competitive with coal power plants, making them one of the cheapest power providers. Also with every new project, the cost is reduced due to the competition of the coal power plants. Finding and exploiting geothermal resources depends on locating the best producing hydrothermal wells, which depends on availability. (Energy Consumers Edge, 1).
Availability
Geothermal power is available where magma finds its way close to the surface of the earth and heats groundwater to temperatures above 100 degrees Celsius. These hot spots don’t occur everywhere, and finding specific locations to drill is a challenge. Many areas have accessible geothermal resources, especially countries along the Pacific “Ring of Fire.”
Figure 1. Hottest Known Geothermal Regions (Geothermal Education Office, 2000).
The figure above demonstrates where all the hottest known hot spots are in the world. In the United States, these spots are located in parts of the Western States, Alaska, and Hawaii. According to the “U.S. Geological Survey Circular 790” estimates a hydrothermal resources base in the United States uses roughly 95,000-150,000 megawatts. Of that power, about 25,000 megawatts are known resources. Even though those numbers are significant, it’s roughly about one fourth of the United States current electrical need. (Energy Consumers Edge, 1). Since most of the geothermal resource is located in the west coast of the United States, it can only be applied to those people and the few living in Alaska and Hawaii. The electrical power would not be able to support the entirety of the United States.
“The big key to universal use of geothermal resources is the development of deep, hot dry rock resources. The key to that is drilling technology. Due to the hot, often corrosive, environment of geothermal resource areas, drilling for geothermal resources is far more expensive than any other kind of drilling.” (Energy Consumers Edge, 1).
This quote shows that drilling in accessible geothermal hot spots is often hard to locate, as well as expensive.
Aesthetics
Geothermal power plants tend to have less aesthetics problems than most other power plants. The plants occupy the smallest space per kilowatt that is generated. They also have the least visual impact of power generation technology. If groundwater could be used as a cooling mechanism, a geothermal plant could be built underground, or within other structures built for other uses. (Energy Consumers Edge, 1). That would end any disagreements of the pros and cons of geothermal energy aesthetic concerns.
Sustainability
Geothermal energy is the most sustainable and renewable source of energy. The earth possesses more usable geothermal energy resources than coal, gas, oil, and nuclear fuels combined. Geothermal resources are a form of nuclear power and can continue to provide energy supplies decade after decade. On the other hand, fossil fuel reserves may be gone in a few decades. (Energy Consumers Edge, 1). This means alternative sources of energy need to be tapped into before we run out of fossil fuels; geothermal energy is one source worth investing in.
Is geothermal energy environmentally friendly?
There is much controversy over whether geothermal energy is harmful towards the environment. Most sources will say that comparatively, geothermal plants are environmentally friendly and may aid the environment. While other sources say that geothermal plants lead to air and thermal pollution, along with chemicals that get carried through the groundwater from geothermal plants. There are many pros and cons on the affects of geothermal energy, but its important to understand and discuss both aspects.
Pros
There are many advantages and disadvantages on the environmental impact of geothermal energy production. Most of the advantages outweigh the disadvantages, and geothermal energy use can actually have a positive affect on the environment. First off, burning fuels to produce energy has created harmful emissions in the environment. This results in acid rain and other pollutants escaping into our atmosphere. The amazing thing about geothermal energy use is that it reduces acid rain by 97%. (Geothermal energy pros and cons, 1). This is due to the fact that there is no purchasing or burning of fossil fuels in a geothermal plant. Another advantage of geothermal energy use is that it is totally renewable. Since it’s renewable, the water supply is replenished through rain and heat is continuously being produced by the earth’s interior. Because of this, the energy is capable of heating and cooling homes or other small-scale facilities without affecting the environment. Geothermal energy plants also reduce negative affects on the environment due to their size. Geothermal plants are not nearly as large as nuclear plants, electrical plants, or huge dams. Since geothermal plants are moderately small, they have less direct impact on the environment. The last thing worth mentioning about the advantages of geothermal energy use on the environment is channel use. After a geothermal plant is established at a specific site, minimum channels or drill points are required to collect the energy for use. (Geothermal energy pros and cons, 1). Thus, geothermal energy production is efficient. This also means that fewer holes are needed for drilling, and once the channels are established, no more need to be created.
Cons
There are many disadvantages of geothermal energy use, and many of them negatively affect the environment. One of the disadvantages of geothermal energy production is locating a site to tap into geothermal resources. Once the site is found, a drill needs to be used to access a place where hot rocks in the layer of the earth’s crust can be used. Once the rocks are accessed, the heat of the water can be pumped into a well at a suitable level. Then the heat from the water can be converted into geothermal energy. The problem with this is locating a suitable drilling area. Since drilling is an expensive endeavor, finding a proper drilling site takes time and other resources. Since drill sites are not easily available or accessible, means that the use of geothermal energy production is hampered. Another negative issue associated with geothermal energy is the emission of gases and water pollution issues. The use of geothermal energy results in the release of hazardous gases such as hydrogen sulfide, which can rise to the surface of the earth through the hot water. (Sabadell, 2). This also leads to trace pollution problems, because other materials that cause health hazards rise to the surface along with the hot water. The three main materials that get brought up to the surface by the steaming water are arsenic, mercury, and ammonia. These materials cause environmental pollution, and are not easy to clean up or deal with.
Rising pollution Issues
Pollution issues from geothermal power plants are starting to surface more than they have in the past. Initially geothermal energy was thought to be extremely clean with little to no environmental affects. This is true compared to nuclear or atomic plants, but pollution is still a rising issue with geothermal plants. The main environmental affects of geothermal development are related to surface disturbances, the physical effects of fluid withdrawal, and the discharge of chemicals. (Robertson, 1094). One of the main pollutants associated with geothermal power plants is mercury.
“Geothermal steam used for power production contains significant quantities of volatile mercury. Much of this mercury escapes to the atmosphere as elemental mercury vapor in cooling tower exhausts. Mercury emissions from geothermal power plants, on a per megawatt (electric) basis, are comparable to releases from coal-fired power plants.” (Robertson, D.E., 1094).
This quote demonstrates that even though geothermal plants are environmentally friendly in some aspects, they still come with pollution issues no different than coal powered plants.
Conclusion
Geothermal energy is an alternative source of energy that contains much potential for its uses, but comes with pollution issues. Geothermal power plants can provide electricity to run a number of applications such as district heating, space heating, industrial processes, and agricultural applications. The main issues associated with geothermal energy use are reliability, cost, availability, aesthetics, and sustainability. The use of this energy is becoming better known by small, developing countries, but comes with air and water pollution. Some critics will argue that geothermal plants have no impact on the environment, when in reality dangerous levels of mercury, arsenic, and other effluents are released. The hazardous waste can be devastating to the environment, but is seen as more environmentally friendly than other sources of energy that burn fossil fuels.
Bibliography/References
Geothermal Plant in Iceland
The main characters from one of my favorite films "Trainspotting"
