Geothermal Energy Abstract The purpose of this report is to introduce the background of geothermal energy, different types of this energy, several applications and some disadvantages of geothermal energy. The scope and limitation of this report include the international development of geothermal energy and it benefits for human beings, thereby, providing incentive for the implementation of development of geothermal energy in Australia. However, due to the geological factor, the cost of the application and the development of technology may not be applicable in Australia.
This report mainly focused on considering the possibilities and problems of using geothermal energy in Australia. Case study is the main method to analyze the development of geothermal energy in different countries. Though secondary research which including scholarly journals, accredited websites show that Australian geothermal resource is potentially huge but little use of geothermal power presently. Geothermal energy has been produced for hundreds years and developed many applications those can catalogue into electricity generation and direct use. Australia is rich in geothermal resources.
However, most of Australia’s geothermal resources are characterized by their medium-to-low enthalpy and are more suitable for direct uses. According to the research some recommendations are suggested. Recommendation1: Incorporate internationally that can develop geothermal technology faster. Recommendation2: Support research in geothermal resource exploration techniques and equipment. Recommendation3: Support development of new direct use applications. Recommendation4: Increased resource information Table of Contents Abstract1 List of Figures2 1. 0 Introduction2 1. 1 Purpose and audience2 1. 2 Scope2 1. Brief history2 2. 0 Background of geothermal energy2 2. 1 Sources of geothermal energy2 2. 2 Types of geothermal energy2 2. 3 Applications of geothermal energy2 3. 0 Geothermal energy in different countries2 3. 1 Geothermal energy in Turkey2 3. 2 Geothermal energy in Japan2 3. 3 Geothermal energy in Australia2 4. 0 Advantages and disadvantages of geothermal energy2 4. 1 Advantages of geothermal energy2 4. 2 Disadvantages of geothermal energy2 5. 0 Conclusion2 6. 0 Recommendations2 7. 0 Reference list2 List of Figures Figure 1: The Earth’s crust, mantle, and core. Top right: a section through the crust nd the uppermost mantle. (Dickson and Fanelli 2004). 6 Figure 2: Location of Geothermal Power Plants in Japan (Kawazoe and Combs 2004, 59). 9 Figure 3: Japanese Geothermal Power – Net Output (MW) (Kawazoe and Combs 2004, 61). 10 Figure 4: The Eromanga (Great Artesian) Basin (Harries et al. 2006, 816). 11 Figure 5: Hot Dry Rock technology (Harries et al. 2006, 819). 12 1. 0 Introduction 1. 1 Purpose and audience Geothermal energy has principally been developed where large heat flows occur in association with volcanic activity. Australia’s conventional geothermal resources are extensive.
The purpose of this report is to introduce the background of geothermal energy, different types of this energy, several ways to use it and some disadvantages of geothermal energy. This report mainly focused on considering the possibilities and problems of using geothermal energy in Australia and it will be addressed to the Director of Western Australian School of Mine, the Paul Dunn. 1. 2 Scope This report will firstly go into an overview of world’s geothermal power development and also the growing in Australia. Case study is the main method to analyze the development of geothermal energy in the worldwide.
The scope and limitation of this report include the international development of geothermal energy and it benefits for human beings, thereby, providing incentive for the implementation of development of geothermal energy in Australia. However, due to the geological factor, the cost of the application and the development of technology may not be applicable in Australia. 1. 3 Brief history Geothermal Energy is extracted from the earth’s natural heat, this energy comes from the lava inside the earth, and in the form of heat is caused by volcanic eruptions and seismic energy (GRS n. . ). When the first mine were exploited for hundreds meters below the ground level, the miner who works underground thought the earth’s temperature increases with depth. 2. 0 Background of geothermal energy 2. 1 Sources of geothermal energy Form Dickson and Fanelli’s point of view ‘the total flow of heat from the Earth is estimated at 42 x 1012 W (conduction, convection and radiation). Of this figure, 8 x 1012 W come from the crust, which represents only 2% of the total volume of the Earth but is rich in radioactive isotopes, 32. x 1012 W come from the mantle, which represents 82% of the total volume of the Earth, and 1. 7 x 1012 W come from the core, which accounts for 16% of the total volume and contains no radioactive isotopes. (See Figure 1 for a sketch of the inner structure of the Earth). Since the radiogenic heat of the mantle is estimated at 22 x 1012W, the cooling rate of this part of the Earth is 10. 3 x 1012 W’(Dickson and Fanelli 2004). Figure 1: The Earth’s crust, mantle, and core. Top right: a section through the crust and the uppermost mantle. (Dickson and Fanelli 2004). 2. 2 Types of geothermal energy
Due to the difference in temperature between the different part of the Earth, generally geothermal energy can classified as low temperature (less than 90°C or 194°F), moderate temperature (90°C – 150°C or 194 – 302°F), and high temperature (greater than 150°C or 302°F). These different types of resources directly influence the application of geothermal energy. For the high temperature resources are used for generation electricity only. Moderate and low temperature resources can be divided into two application areas: direct use and ground-source heat pumps (GRC n. d. ). 2. 3 Applications of geothermal energy
There are two ways to use geothermal energy one is to generate electricity and the other is for direct use. The temperature of geothermal resources is the main reason to determine whether to generate electricity or use directly. High temperature resources is used for generate electricity and medium-low temperature are usually for direct use. In Australia, direct use of geothermal heat could be used in greenhouse heating or crop drying and in aquaculture as well. It could also be used for industrial processes such as wool processing, drying organic materials and so on (Geosciences Australia n. . ). 3. 0 Geothermal energy in different countries 3. 1 Geothermal energy in Turkey Turkey is a typical country of using geothermal energy, high enthalpy is used for generation electricity and low temperature resources is for direct use. Starting in the early 1960s the first geothermal exploration was focused on high temperature resources for potential power generation. A second high temperature fields and other medium temperature systems were found in the 1980s. From Serpen’s point of view is that Turkey’s geothermal resources base is about 3×1023 J.
More than 270 hot springs have been identified most of them are low-to-medium enthalpy geothermal systems. The high temperature resources able to generate about 1400 MWe of electricity. There are several applications of direct use of geothermal energy resources in Turkey such as: ‘district heating, health spas, greenhouse heating and some other direct uses. At end of 2008, nearly 6 million m2 of indoor space is being heated in 20 district systems and the total capacity is around 395MW’ (Serpen, Aksoy, Ongur and Korkmaz 2009, 232). Another application of geothermal energy is health spas.
Turkey has many natural warm springs with medicinal effect. Those warm springs can treat different kinds of illnesses and can attract a lot of visitors to these health spas. According to Serpen Cesme will be the most important spa center in Turkey if the local government decided to build a 42-km long pipeline to provide 18 major hotels with geothermal water. The amount of geothermal energy being used in Turkey’s geothermal health spas and swimming pools is about 220 MWt. The third application geothermal power used in Turkey is greenhouse heating.
Recently using geothermal power to heat greenhouse is very popular in Turkey and the total usage is about 180MWt (Serpen et al. 2009, 233). There also some other direct uses of geothermal energy in Turkey such as ‘drying food and agricultural products, the amount of uses could be about 795 MWt’ (Serpen et al. 2009, 233). By studying the case, the use of Turkey’s geothermal resources will increase in the future. 3. 2 Geothermal energy in Japan Japan is one of the most active volcanic countries in the world, with almost 200 volcanoes that means Japan has huge geothermal energy resources.
The substance of Kawazoe’s article is that 20 geothermal power plants were in operation at 18 different cities in Japan (see Figure 2). Most of them are located in the Kyushu and Tohoku districts. The amount of installed capacity is 535. 25 MW, it makes Japan the sixth largest generate geothermal electricity in the world. The country has cold winters and little heating, so the hot bath has been a national ritual from early times and for this reason Japan is the world’s largest user of direct geothermal energy resources. By developing three generations from mid-1960s to present, Japan’s geothermal power capacity is increased from 31MW to 535. 5 MW (see Figure 3) which is ‘about 0. 2% of total power capacity in the country. Electricity produced by geothermal energy during April 2002 – March 2003 is about 0. 4% of total annual electricity production’ (Kawazoe and Combs 2004, 60). By studying this case, Japan is the world’s sixth largest producer of electricity from geothermal energy resources. In developing those resources, Japan has made important role of contribution to world geothermal development. Figure 2: Location of Geothermal Power Plants in Japan (Kawazoe and Combs 2004, 59). Figure 3: Japanese Geothermal Power – Net Output (MW) (Kawazoe and Combs 2004, 61). . 3 Geothermal energy in Australia Australia has huge conventional geothermal resources, but lots of the resource are located in the areas of low population density so the result is that there are neither used for generate electricity nor direct heating. According to Harries ‘the existence of wet geothermal or hydrothermal resources and hot dry rock (HDR) is due to an abundance of high temperature granite occurring at depth of less than 5km and covered by water-bearing sedimentary layers that act as effective thermal insulators that keep the granite at twice the usual temperature of granite at such depth.
About 80% of these geothermal energy resources are located in the Cooper Basin and the Eromanga (Great Artesian) Basin’ (Harries, Mchenry, Jennings and Thomas 2006, 816). (see Figure 4) Figure 4: The Eromanga (Great Artesian) Basin (Harries et al. 2006, 816). There are three major geothermal systems were used to generate electricity, geothermal heat pump systems, geothermal aquifer resources and hot dry rock systems. Close–to-surface ground heat is used as a source for electric heat pumps. The total installed capacity is 24MW in 2001 and will be increasing 50% per year.
Geothermal aquifer resources in other words is wet geothermal resources. Because of the low temperature and in the low population density. There are only two small wet geothermal systems have been built for remote settlements in Australia. Another system is called hot dry rock system. The Hot Rock system is a closed-loop system that requires at least one fluid injection well and one production or recovery well. Liquid is pumped down the injection well and travels through the rock fracture network to be heated by the hot rocks.
The superheated fluid then returns to the surface in the production well(s), transfers its heat to a secondary fluid or working fluid, and is then recirculated and pumped down the injection well(see Figure 5). There are currently no Hot Rock systems generating electricity on a commercial scale anywhere in the world due to the cost of producing electricity from it (Harries et al. 2006, 817-820). Figure 5: Hot Dry Rock technology (Harries et al. 2006, 819). Direct use is another application of use geothermal energy.
An example of direct-use application is in Portland(Western Victoria) where four deep wells provide 56-59? water to a district-heating servicing a total of 18,990 m2 building area and the total installed capacity is 10. 4 MWt (Lund, Freeston and Boyd 2005, 721). 4. 0 Advantages and disadvantages of geothermal energy 4. 1 Advantages of geothermal energy With the increase in world population, industrialization and improvement in the standard of living, there are has been a continuous increase in consumption of energy. Due to the reserves of fossil fuels geothermal energy will play an important role in the future.
Geothermal energy is unlike the oil, natural gas and coal, it is considered to be a relatively clean and renewable energy resource, widely use geothermal energy can reducing emission of CO2 and other atmospheric pollutants which is from using fossil fuels. Geothermal energy has many advantages firstly, geothermal energy is a renewable and clean energy. Furthermore direct use of geothermal resources can give many benefit for humans, for example district heating, health spas and greenhouse heating. In addition, electricity generation from geothermal resources is more economical than other renewable resources.
According to a comparison from Fridleifsson shows ‘the current electrical energy cost to be 2-10 US? /kWh for geothermal and hydro, 5–13 US? /kWh for wind, 5–15 US? /kWh for biomass, 25–125 US? /kWh for solar photovoltaic and 12–18 US? /kWh for solar thermal electricity’ (Fridleifsson 2001,299). 4. 2 Disadvantages of geothermal energy Although geothermal energy has lots of benefit for human being, there are still some disadvantage of geothermal power. First of all, geothermal energy always occur around volcanos and fault lines. Because of this, it is difficult to find a suitable place to built geothermal power plants.
Secondly, direct use is a principal application of geothermal resources. The most important problem is that the hydraulic characteristics of the thermal resources have been completely ignored in their design ( Serpen et al. 2009, 232). 5. 0 Conclusion Geothermal energy has been produced for hundreds years and developed many applications those can catalogue into electricity generation and direct use. Australia is rich in geothermal resources. The Great Artesian Basin provides a huge hydrothermal resource. The Hot Dry Rock has a high resource in Australia and therefore would have a high potential to be vastly resourced.
However, most of Australia’s geothermal resources are characterized by their medium-to-low enthalpy and are more suitable for direct uses. 6. 0 Recommendations According to the research some recommendations are suggested to the Director of Western Australian School of Mine, the Paul Dunn. * Incorporate internationally that can develop geothermal technology faster. * Support research in geothermal resource exploration techniques and equipment. * Support development of new direct use applications. * Increase resource information 7. 0 Reference list Ayling, B. F. 2007.
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Geothermal resources council. n. d. What is geothermal? http://www. geothermal. org/ (accessed April 1, 2010). Gupta. H. , and S. Roy, 2006. Geothermal Energy: An Alternative Resource for the 21st Century. UK: Elsevier. Harries, D. , M. Mchenry, P. Jennings, and C. Thomas. 2006. Geothermal energy in Australia. International of Environmental Studies 63(6): 815-821. http://www. proquest. com/ (accessed March 15, 2010). Kawazoe, S. , and J. Combs. 2004. Geothermal Japan. GRC Bulletin. http://www. geothermal. org/ (accessed April 1, 2010). Lund, J. W. , D. H. Freeston, and T. L. Boyd. 2005.
Direct application of geothermal energy: 2005 Worldwide review. Geothermics 34: 691-727. http://www. sciencedirect. com/ (accessed March 16, 2010). Russo, S. L. , C. Boffa, M. V. Civita. 2009. Low-enthalpy geothermal energy: An opportunity to meet increasing energy needs and reduce CO2 and atmospheric pollutant emissions in Piemonte, Italy. Geothermics 38(2): 254-262. http://www. elsevier. com/ (accessed March 16, 2010). Serpen, U. , N. Aksoy, T. Ongur, and E. D. Korkmaz. 2009. Geothermal energy in Turkey: 2008 update. Geothermics 38(2): 227-237. http://www. elsevier. com/ (accessed March 15, 2010).