Environmental Impacts of Geothermal (Research Paper Sample)

ENVIRONMENTAL IMPACTS OF GEOTHERMAL 
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Environmental Impacts of Geothermal: Tuscarora Facility
Introduction
Research has demonstrated that geothermal facilities are far less destructive as compared to other power plant technologies such as fuel plants (INL 2010, 4).In order to evaluate the actual environmental impacts of a given plant, it is important to focus on a particular area affected by a given power plant. Such a study is necessitated by the fact that the impacts of geothermal technology are dependent on the particular environment and other localized facets. In the modern day, geothermal is characterized as a green source of energy owing to multiple benefits it poses to the environment, however, exploitation of steam that is used to during the construction and operation of mega geothermal, induce minimal negative implications to the environment (The Carbon Neutral Company. Pg1). Such implications are better understood through an intensive study that focuses on a particular region. Geothermal harnessing is associated with studies on water quality, air quality, land use, biological resources, noise as well as waste disposal. To successfully evaluate the environmental impacts of geothermal, this paper looks into the Tuscarora Facility, which is located in Nevada, USA (Elko County Commission department of energy, 2015 pg 1). The paper focuses on the environmental implications associated with the construction and operation of the power plant. The paper begins by looking at the various structures that makes up the power plant and then explores particular environmental impacts. It also focuses on mitigation measures that have been put in place to minimize the environmental effects. The paper also compares the environmental impacts emanating from the geothermal plant to those of fossil fuel power plants.
The Tuscarora Facility
As mentioned earlier, this facility is located in Nevada. It is about 70 miles north of Elko in the independence valley. It is located about three miles to the north of the Spanish Ranch building complex. The entire project has two power plants phase 1 and phase 2 each with a capacity of 19Mw net. This plant consists of several feeder wells, an access load, a transmission line, and the generating plant itself. Various wells are located on private land which was leased from Ellison Ranching Company. The plant’s total production is evacuated via a 24.5-mile, 120KV transmission line, which is located on private land within the independence valley. The transmission line evacuates power from the plant to NV Energy’s Humboldt Substation for further transmission. The area can be accessed via two routes SR 225 to SR 226. The plant’s well pads, steam wells and associated pipes occupy about 62.8 acres of private land Summary of the Plant/ Facility
In order to understand the environmental effects of the plant, it is important to have a brief overview of the plants operating mechanism and structure. The plant consists of a number of facilities and auxiliaries. It is composed of:
Generating Facility
Production Wells
Re-injection wells
Pipelines
Fresh water wells
Office facilities
Generating Plant
This plant works on the principle of the Rankin cycle and is similar to any other plant that operates on the same principle. Steam is conveyed to the plant via pipelines which are connected from the well field into the generating plant. On reaching the plant, the steam is used to vaporize a secondary fluid that is used to provide the mechanical energy, which rotates the turbine of the generator to produce electrical energy (Elko County Commission department of energy 2015 pg 3) The generating plant consists of a two generators driven by four turbines with a net output of 19MW. The generators convert mechanical energy to electrical energy which is evacuated for transmission. The geothermal fluid emerging from the generator is taken to a heat exchanger where heat is lost and re-injected into the ground via re-injection wells. Four condensers are incorporated in the plant and have the role of condensing the steam into a fluid. From the condenser, the cooling water goes to the cooling tower where it is cooled by cold water normally pumped into the tower by cold water pipes.
Production Wells
The facility makes use of three production wells which are located in the private land well field. These wells were drilled between 2008 and 2011 and have the capacity to supply the required steam to generate 19MW. Each of the wells is drilled to a depth of about 5000 feet in accordance to stipulated standards by Nevada Davison of Minerals.
Injection Wells
This facility is served by four re-injection wells which are used to re-inject condensed fluids back into the geothermal aquifer. This re-injection plays an important role in ensuring environmental stability and preventing disasters such as land sinks. Additionally, a fifth well is also used to re-inject the cooling water blow down into the ground. This also helps to retain the natural balance in the environment.
Pipelines
The facility is served by pipelines which transport steam from the production wells into the generating plants. Another set of pipes is used to transport the geothermal fluid from the cooling tower back to the re-injection wells. A final set of pipes is used to transport fresh water from the fresh water wells to the various parts of the power plant, offices and the cooling tower (Elko County Commission department of energy 2015, pg 6)
Fresh Water Wells
The facility is served by two fresh water wells which are used to supply the required water to the various offices in the plant and the cooling tower. Fresh water wells are located in the private fields and connect to the facility via a set of pipes.
Auxiliary Offices
The plant is served by several buildings which include an office building, the generator room, machine shop, control room, toilets and bathrooms. These facilities are constructed to the southern side of the power plant.
Environmental Impacts
In order to counter various environmental impacts the plant has adopted environmental impact standards which guided the process of construction and are used in the repair, maintenance and operation of the facility. These environmental protection measures are geared towards protecting the air, water resources, various organisms and human health in general. Despite the environmental measures, various limited impacts into the environment are still significant enough to attract attention from researchers. These impacts are analyzed in various categories which are discussed in the following sections.
Air Quality
Like other geothermal plants, air quality issues are significant areas of interest while dealing with this particular power plant. This plant is associated with the release of various gases at various levels despite stringent measures taken to minimize such gases. Air quality issues are discussed with respect to global warming, toxic gases, particulate emissions and the formation of acid rain (INL 2010, 6). Although this plant is far much better than any fuel fired plant with regard to air quality, minimal effects are still important aspects of consideration. Nevada area is associated with a high concentration of H2S gas. This gas is nuisance at low levels of concentration and toxic at a high level of concentration. This effect is quite significant due to the various leakages at different parts of the generation process. Exposure of the geothermal fluid at the cooling tower also leads to the release of this gas into the environment. Particulate matter is also known to cause respiratory problems to human beings. However, due to stringent environmental measures that have been put in place, there is an insignificant release of particulate, matter associated with the generator. Acid rain formation for this acid is not a significant consideration. This is because sulfur and nitrogen are not significantly released by the processes involved in the generation (Geothermal Ex, 2009 pg 112). Co2 release by the process of generation, pose a challenge to the environment. Although minimal carbon dioxide is released it is still significant, especially due to global warming, which poses a serious danger to the environment (Geothermal Energy Association 2012, 4) A fossil fuel power plant of the same capacity we induce much more destructive impacts. It is associated with the release of carbon dioxide, particulate matter, nitrogen oxides, and sulfur dioxide. These gases cause respiratory problems, global warming and acid rains.
To reduce these environmental impacts various standards have been adopted. Fugitive dust is continuously controlled using chemical and water suppressants. In addition, BMPs standards have been applied to ensure that additional dust is dealt with accordingly.
Bureau of Air Pollution Control standards is used to specify requirements for various generator parts to prevent emissions (Ľudovít C et al 2010).
Water Resources
The central water resource affected by the Tuscarora power plant is Hot Creek. This resource is a perennial stream running from north to south. A second water tower affected by the facility is the Harrington Creek flowing eastwards from the location of the plant. This second creek is a cold water resource located above hot Sulphur springs in the region. Ground water is also a significant water resource that is susceptible to degradation by the presence of geothermal wells in the region. Various dangers are eminent from geothermal activities in the region. The First danger is the danger of mixing shallow underground water with the geothermal fluids which may contain dissolved toxins such as mercury...