Energy and Low Carbon Technology: Geothermal Technology - Report Example

Energy and Low Carbon Technology: Geothermal Technology Student’s Name Course Name & Number Date of Submission Table of Contents Table of Contents 2 1.0 Introduction 3 2.0 Geothermal Statistics 3 3.0 Geothermal Resource 4 4.0 Process of Capturing Geothermal Energy 5 4.1 Dry Steam 5 4.2 Flash Steam 6 4.3 Binary Cycle Power Plant 8 5.0 Emerging Technologies 8 6.0 Future of Geothermal Energy 9 7.0 Conclusion 10 References 12 1.0 Introduction Energy is regarded as the engine that drives economies. Energy is required to power the various industries, such as manufacturing, transport and businesses, as well as homes. Accordingly, this implies that no economy can do without energy. However, studies indicate that the world still relies heavily on fossil fuels, such as oil, natural gas, and coal as the main source of energy. According to the world Atlas (2016) report, at least 29 nations derive at least 90% of their energy from fossil fuel key among these countries are the UK, China and the United States. Nonetheless, with the impending peak oil, climate change and global petroleum crisis, countries have had to rethink about their energy policies and how they need to power their economies. Huenges and Ledru (2011, p. 2) argue that no part of the world is spared of the adverse effects of climate change that includes prolonged droughts, increased flooding, rising sea levels, high glacial movements and increased typhoons and wildfire, as well as increased public health risks. However, scientists have attributed the global warming effects to excessive use of fossil fuel that results in heavy emission of greenhouse gases (Dickson & Fanelli 2013, p. 4). The concern now is that if countries fail to act decisively to mitigate global warming, then the world will be no more by the next century. For this reason, most countries are increasingly shifting to low carbon energy technologies as a way of cutting down their dependence on fossil fuel so as to address climate change situation. The UK is among the countries that are working towards cutting their carbon footprint by shifting to greener energy sources, such as wind, solar, hydro and geothermal energy. According to the Green Match (2016), the UK government hopes to increase its low carbon energy production by 40% by 2020 and to cut its greenhouse gas emission by 34% by 2020 and one of the low carbon technologies targeted by the UK government and other nations is geothermal. This paper will describe geothermal energy beginning with statistics following by a description of how geothermal energy is captured, emerging trends and finally its future as a source of energy. 2.0 Geothermal Statistics Geothermal is one of the low carbon technologies that most nations of the world are shifting as they seek to lower their dependence on fossil fuel and address the problem of climate change. As at 2013, there were more than 11, 7000 megawatts (MW), high capacity geothermal energy stations in operations worldwide with the same number expected to be added over the next few years. The existing geothermal power stations produced about 68 billion KW-hours of electricity, which was enough to meet the annual electricity needs of more that 6 million people. Statistics indicate that geothermal currently accounts for more than 25% of Iceland and El Salvador’s electricity production (World Atlas, 2016). The United States is currently the global leader in geothermal energy production as the country has more than 3,300 MW of geothermal energy in eight states (Union of Concerned Scientists 2014). Presently, thousands of the U.S. households and buildings use geothermal power for electricity and heat pumps among other purposes, cleanly and inexpensively. The UK, however, despite its potential for geothermal energy, geothermal energy remains under exploited, according to the Green Match (2016) report. 3.0 Geothermal Resource Geothermal energy is produced from steam generated several miles below the earth’s surface. According to scientists, there are layers of hot and molten rocks below the earth’s crust called magma. The hot magma results from continuous heating of this layer, which is made of radioactive materials, such as potassium and uranium. According to the Union of Concerned Scientists (2014), heat generated within a distance of 10,000 meters below the earth’s surface is capable of producing 50,000 times more energy than the entire oil and gas resources globally. The statistics is an indication that geothermal energy if adequately invested in and harnessed, is enough to power the whole world, thus addressing the problem of climate change that the world is currently grappling with. However, geologists state that areas with active and young volcanoes are the more suited for the production of geothermal energy because of the high underground temperatures in such areas. The “hot spots” are said to occur within the boundaries of the tectonic plates or at the points with thin crust layers, which allow heat through. In the United States, areas, such as the Ring of Fire with its many young volcanoes have hundreds of hot spots with potential of producing large geothermal energy. In the UK, hot spots are found in areas, such as Wessex, the Lake District, the Eastern Highlands of Scotland, South West England and Cheshire among others (Green Match 2016). These areas are also said to be seismically active in the sense that they are prone to earthquakes and magma movements, which results in the breakup of the layer that covers the crust, thus allowing hot water to circulate. When the hot water rises up the surface, geysers and hot springs occur. (Dickson and Fanelli (2013, p. 14) state that the hot water that seeps from underground could be as hot as 200oC of more. It is important to understand that it is not only seismically active hotspots that have the potential of generating geothermal energy. Instead, geothermal energy can be generated from any location of the earth at a depth of from 10 to a few hundred feet below the surface of the earth because of enough heat generated underground in any location. According to the Union of Concerned Scientists (2014), even the grounds below homes, schools and churches have enough heat underground that can be turned into geothermal power. The report also indicates that, regardless of the location, from 4-10 kilometers below the earth’s surface, there are large amounts of heat generated from dry rock formation that can easily be taped using the latest technologies, such as Enhanced Geothermal Systems (EGS) (Huenges & Ledru 2011, p. 82). Although the EGS technology is still in the infancy stage, where it is still being tested in countries such as Australia and the United States, this technology has the potential of increasing the geothermal energy capacity in the event that it succeeds. It is believed that, in the event that the full economic potential of geothermal is achieved, geothermal would accounts for a large percentage of electricity production globally. According to the U.S. National Renewable Energy Laboratory (NREL) 2012 report, conventional geothermal sources in 13 states have the potential of generating 38,000MW capable of adding 308 million MWh of electricity every year (Union of Concerned Scientists 2014). 4.0 Process of Capturing Geothermal Energy At present, geothermal energy is captured naturally through the hydrothermal convection system, whereby hot water from below the earth’s surface is captured and directed to the installed turbines. The steam water rotates the turbines at high speed, which then activates the generator, which converts the thermal energy into electricity. To achieve this, geothermal power facilities start by drilling holes deep below the earth’s surface until it reaches the desired rock where the hot steam is generated so as to allow the steam to be captured (Dickson & Fanelli 2013, p. 41). However, there are three types of geothermal power plant designs commonly in use to generate electricity namely dry steam, flash steam and binary steam. 4.1 Dry Steam Dry steam is one of the geothermal power plant designs commonly used in different parts of the world to generate geothermal power. This design was named so because the extracted underground water has to be in gaseous form (fig. 1). Under this design, underground steam of at least 150oC is extracted from the underground reservoirs is send to straight to the turbines/generators, where the hot steam is condensed into water and then converted into electric power and then to the power grid for use by industries and households (Union of Concerned Scientists 2014). This is arguably the oldest and simplest method of generating geothermal power with the first power plant of this design having been built in Italy in 1904. In the United States, there are only two known dry steam geothermal power plants namely Geysers in Northern California and the other one in Yellowstone National Park, Wyoming. Figure 1: Dry Steam technology Source: Maehlum (2013). 4.2 Flash Steam Flash steam is now among the most common geothermal power plants developed across the globe. This is a type of geothermal power plant that uses hot water of temperatures of at least 182oC (360oC) (Union of Concerned Scientists 2014). This type of geothermal energy production derived its name ‘flash” from the fact that the process of power generation involves flashing of hot water at high pressure into steam inside a flash tank (fig. 2). As hot water flows from underground upwards, the flashing processes results in a reduction in pressure, as part of the water boils into steam. It is this steam that is isolated from water and sent directly to turbines at high pressure, which rotates the turbines, resulting in the generation of electric power. In the process, some water may be left due to condensation of steam (Dickson & Fanelli 2013, p. 49). These waters are usually injected back into the steam reservoir for heating and steam generation to ensure that the process does not stop. Accordingly, flash steam is regarded as a sustainable resource for generating electric power from geothermal. New Zealand’s Wairakei Power plant built in 1958 was the first geothermal power plant to use flash stream technology (fig. 3). Today, this technology is very common and is widely used in geothermal power stations in most parts of the world. Figure 2: Flash stem technology Source: Maehlum (2013). Figure 3: New Zealand's Wairakei geothermal power station Source: Union of Concerned Scientists (2014). 4.3 Binary Cycle Power Plant Binary circle power plant is a technique in which geothermal power is generated from water at temperatures which are as low as 570C (Union of Concerned Scientists 2014). In fact, this is one of the major advantages of binary circle technique over the steam and flash techniques. In binary circle geothermal power plant, heat emanating from hot water is used to boil a working fluid, which in most cases consists of organic matter with a low boiling point. Once the working fluid has been heated to the desirable temperatures, the vapor is channeled into a heat exchanger, where it is used to move the turbines. Remaining water is injected back into the reservoir for reheating. However, during the entire process, water and the working fluid are isolated from each other to prevent air from escaping. The first binary circle geothermal plant was built in Russia in 1967 and has since become a common technique for harnessing geothermal power (Maehlum, 2013). Source: Maehlum (2013). 5.0 Emerging Technologies It is important to note that, apart from the three basis geothermal technologies described above, there are other emerging technologies that are in their infancy stage that if successful, could help in production of geothermal power even in areas where the above three technologies have not succeeded. The first emerging and promising technology is the Enhanced Geothermal System otherwise called ‘hot dry rock” (Union of Concerned Scientists 2014). Hot dry rocks are located far below the earth’s surface that other conventional technologies, such as dry steam, flash steam and binary circle technologies cannot. Under this technology, water is pumped through the broken hot rocks by plants, after which it is heat up and channeled to the surface as steam that powers the turbines, thus resulting in the production of electricity. The remaining water is injected back to the reservoir through wells to finish the circulation. This emerging technology that is still at the testing stage in Australia and the U.S. will make it possible for engineers to generate geothermal power from anywhere, including in dry areas as opposed to the current technologies that target mainly young volcanoes and seismic prone areas. The other promising technology is Low-temperature and co-produced geothermal technology. This technology generates energy from the underground geothermal fluid at temperatures of 1500C or less. Energy produced from this technology is capable of being used to produce power through binary cycle geothermal processes (Union of Concerned Scientists 2014). 6.0 Future of Geothermal Energy Geothermal energy has the potential of moving the UK and the rest of the world towards a cleaner, efficient, cost-effective and sustainable energy. Geothermal energy is among the low carbon technologies with the capacity to supply the world with continuous base-load energy. For instance, unlike solar, and wind power whose supply vary depending on whether condition, geothermal power provide stable continuous power regardless of the whether condition and this makes it one of the energies that would be preferred for the future (Huenges & Ledru 2011, p. 8). Additionally, geothermal energy is considered the energy for the future because this energy is relatively cheaper compared to other sources of energy such as natural gas. According to a report by the U.S. Energy Information Administration (EIA), the cost of geothermal energy will be less than 5 cents for every kilowatt hour. This is in contrast to that of natural gas plants that are more than 6 cents per KWh and more than 9 cents for coal (Union of Concerned Scientists 2014). Accordingly, the low cost associated with geothermal energy compared to other energy sources makes the future of this energy source bright and this is demonstrated worldwide as countries are doing everything possible to increase their geothermal power capacity so as to reduce the cost of energy in their countries. Lastly, geothermal energy is considered the energy for the future because of the fact that it is one of the greenest sources of energy. As earlier highlighted in the inductor part of the paper, the world is currently grappling with the global warming problem. Climate change is a reality and the world leaders are trying to find the solution to this phenomenon whose adverse impact is being felt in the entire world. Some of the impacts of climate change include increased prolonged drought, flooding, and glacial movements, rising sea levels, typhoons and wildfires among others. Additionally, the global warming effect is believed to be partly responsible also for the increased health problems that are currently being felt across the globe, such as cancer (Dickson & Fanelli 2013, p. 5). Besides, breathing in some cities of the world have started becoming a problem due to pollution, as is the case in large cities such as New Delhi, India, London, UK and New York, USA. The global warming problem is associated mainly with the world’s overreliance on fossil fuel that produces large amounts of greenhouse gases. Fortunately, geothermal energy is clean and less pollutant. The only emission from geothermal are those associated with its production process. Therefore, because geothermal is a green energy, the world is increasingly shifting to this renewable source of energy not just as a means of increasing energy capacity, but also as a strategy for mitigating the global warming effect. For this reason, the harnessing and production of geothermal power is expected to continue in the foreseeable future. At present, there are only 10,715 MW geothermal power plants in 24 nations, which is very little considering the world’s electricity consumption capacity (Union of Concerned Scientists 2014). However, the amount of geothermal energy is expected to increase by more than double digit over the next decade as more and more countries invest in this low carbon technology. 7.0 Conclusion Geothermal energy is one of the low carbon technologies that are increasingly being embraced as the solution to the fossil fuels that have dominated the energy industry for many years. As indicated in the paper, geothermal energy is energy produced from underground steam that are sent to the turbines to generate electricity that is then sent to the power grid for use in industries and homes. The energy is also used for cooling and heating homes. There are basically three technologies commonly used in geothermal power plan, which include dry steam, flash steam and binary circle. The choice of the technology is determined by the resources. However, there are other emerging technologies that are still in their infancy stages being tested that if successful could enable countries to generate geothermal even in areas that the other three technologies cannot generate power. The two new technologies are Enhanced Geothermal System and Low-temperature and co-produced geothermal technology. It has also emerged from the discussion that geothermal will remain one of the energies for the future because it is sustainable, cheaper compared to other sources, such as natural gas and goal and above all, the fact that it a clean energy. References Dickson, M. H., & Fanelli, M 2013, Geothermal energy: Utilization and technology. Routledge, New York. Huenges, E., & Ledru, P 2011, Geothermal energy systems: Exploration, development, and utilization. John Wiley & Sons, Hoboken, NY. Green Match 2016, Is the UK harnessing its geothermal energy resources? viewed 11 March 2017 http://www.greenmatch.co.uk/blog/2014/08/is-the-uk-harnessing-its-geothermal-energy-resources Maehlum, M. A 2013, How a geothermal power plant generates electricity, viewed 11 March 2017 http://energyinformative.org/how-a-geothermal-power-plant-generates-electricity/ Union of Concerned Scientists. 2014, How geothermal energy works, viewed 11 March 2017 http://www.ucsusa.org/clean_energy/our-energy-choices/renewable-energy/how-geothermal-energy-works.html#.WMLdBbj-sdU World Atlas 2016, Fossil fuel dependency by country, viewed 11 March 2017 http://www.worldatlas.com/articles/countries-the-most-dependent-on-fossil-fuels.html Read More