Geography
Geothermal Power
Geothermal power is a renewable energy source that harnesses heat from the Earth's core to generate electricity. This is typically done by tapping into natural reservoirs of hot water and steam beneath the Earth's surface. Geothermal power plants produce minimal greenhouse gas emissions and provide a reliable source of energy, making them an important component of sustainable energy production.
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12 Key excerpts on "Geothermal Power"
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Library Press(Publisher)
____________________ WORLD TECHNOLOGIES ____________________ Chapter- 6 Geothermal Power and Hydro Power Geothermal Power Steam rising from the Nesjavellir Geothermal Power Station in Iceland Geothermal energy (from the Greek roots geo , meaning earth, and thermos , meaning heat) is power extracted from heat stored in the earth. This geothermal energy originates from the original formation of the planet, from radioactive decay of minerals, from volcanic activity and from solar energy absorbed at the surface. It has been used for bathing since Paleolithic times and for space heating since ancient Roman times, but is now better known for generating electricity. Worldwide, about 10,715 megawatts (MW) of Geothermal Power is online in 24 countries. An additional 28 gigawatts of direct geothermal heating capacity is installed for district heating, space heating, spas, industrial processes, desalination and agricultural applications. ____________________ WORLD TECHNOLOGIES ____________________ Geothermal Power is cost effective, reliable, sustainable, and environmentally friendly, but has historically been limited to areas near tectonic plate boundaries. Recent technological advances have dramatically expanded the range and size of viable re-sources, especially for applications such as home heating, opening a potential for widespread exploitation. Geothermal wells release greenhouse gases trapped deep within the earth, but these emissions are much lower per energy unit than those of fossil fuels. As a result, Geothermal Power has the potential to help mitigate global warming if widely deployed in place of fossil fuels. The Earth's geothermal resources are theoretically more than adequate to supply hu-manity's energy needs, but only a very small fraction may be profitably exploited. Drilling and exploration for deep resources is very expensive. Forecasts for the future of Geothermal Power depend on assumptions about technology, energy prices, subsidies, and interest rates.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Academic Studio(Publisher)
____________________ WORLD TECHNOLOGIES ____________________ Chapter- 6 Geothermal Power and Hydro Power Geothermal Power Steam rising from the Nesjavellir Geothermal Power Station in Iceland Geothermal energy (from the Greek roots geo , meaning earth, and thermos , meaning heat) is power extracted from heat stored in the earth. This geothermal energy originates from the original formation of the planet, from radioactive decay of minerals, from volcanic activity and from solar energy absorbed at the surface. It has been used for bathing since Paleolithic times and for space heating since ancient Roman times, but is now better known for generating electricity. Worldwide, about 10,715 megawatts (MW) of Geothermal Power is online in 24 countries. An additional 28 gigawatts of direct geothermal heating capacity is installed for district heating, space heating, spas, industrial processes, desalination and agricultural applications. ____________________ WORLD TECHNOLOGIES ____________________ Geothermal Power is cost effective, reliable, sustainable, and environmentally friendly, but has historically been limited to areas near tectonic plate boundaries. Recent technological advances have dramatically expanded the range and size of viable resources, especially for applications such as home heating, opening a potential for widespread exploitation. Geothermal wells release greenhouse gases trapped deep within the earth, but these emissions are much lower per energy unit than those of fossil fuels. As a result, Geothermal Power has the potential to help mitigate global warming if widely deployed in place of fossil fuels. The Earth's geothermal resources are theoretically more than adequate to supply humanity's energy needs, but only a very small fraction may be profitably exploited. Drilling and exploration for deep resources is very expensive. Forecasts for the future of Geothermal Power depend on assumptions about technology, energy prices, subsidies, and interest rates.
eBook - PDF- David R. Boden(Author)
- 2016(Publication Date)
- CRC Press(Publisher)
1 1 An Overview of Energy KEY CHAPTER OBJECTIVES • Describe and contrast nonrenewable and renewable sources of energy. • Identify characteristics that make geothermal energy distinctive from other forms of renewable energy and describe how temperature affects how geo-thermal energy is utilized. • Recognize the difference between energy and power and apply the terms in the correct context. • Discuss the attributes of geothermal energy in terms of fuel source, emis-sions, and baseload. Succinctly, geothermal energy is heat from the Earth that can be harnessed and used for the benefit of society. Geothermal energy is below us everywhere and is available all the time, unlike other forms of renewable or alternative energy, such as solar and wind. And, yet, in many ways geothermal is overlooked because peo-ple are not able to see it like sunshine or feel it like wind. Geothermal, unlike solar and wind energy, is a baseload energy resource capable of providing power 24 hours a day all year long, similar to traditional fossil-fuel-fired power plants. This chapter provides a cursory overview of all forms of energy to provide a perspec-tive of how geothermal energy fits into the energy milieu. Also, key concepts on energy and power are reviewed so the reader understands how energy and power are related and measured. BASIC TERMINOLOGY OF ENERGY AND POWER Energy comes in many forms, including kinetic (energy of motion), potential (the ability to deliver energy), chemical (energy in fossil fuels, such as gasoline and natu-ral gas), and of course thermal or heat energy. The heat energy of the Earth is enor-mous and so is its ability to do work. Examples of Earth’s work include moving huge pieces of the Earth’s crust and uppermost mantle a few centimeters every year, the eruption of volcanoes, and the episodic lurching and shaking during an earthquake.
eBook - PDFGeothermal Energy
Renewable Energy and the Environment, Second Edition
- William E. Glassley(Author)
- 2014(Publication Date)
- CRC Press(Publisher)
201 10 Generating Power Using Geothermal Resources The production of electricity using geothermal energy employs technology that is fundamentally indistinguishable from that at most other power generating facilities. Specifically, an electrical gen-erator is powered by a turbine that converts thermal or kinetic energy into electricity. In fossil-fueled power plants, thermal energy drives the turbine, whereas in hydropower plants, the kinetic energy derived from flowing water drives the turbines. However, in two important respects Geothermal Power production is unique when compared to other power production methods. First, when com-pared to power generating technologies that supply baseload power, such as fossil-fueled power plants, biomass reactors, or nuclear reactors, there is no fuel cycle required to generate heat because the heat already exists within the earth. Second, when compared to other renewable energy tech-nologies that do not require a fuel cycle for heat generation, such as wind, solar, tidal, or ocean wave technologies, geothermal is not intermittent and provides true baseload capability at a reliability that consistently exceeds 90 % . The remainder of this chapter addresses the physics of power generation as it relates to Geothermal Power production and design issues that are specific to particular types of geothermal resources. For a detailed discussion of Geothermal Power plant design see the presenta-tion by DiPippo (2008). HISTORY OF Geothermal Power PRODUCTION The first production of electricity from geothermal steam took place in Larderello, Italy, in 1904. Larderello is in a region of Italy with substantial recent volcanic activity, including explosive steam eruptions that occurred as recently as the late 1200s. With the growth of the Industrial Revolution, interest in exploiting the geothermal resource of the area grew, beginning with the direct use of steam at Larderello to support a local chemical separation industry.
eBook - PDF- Sunggyu Lee, James G. Speight, Sudarshan K. Loyalka, Sunggyu Lee, James G. Speight, Sudarshan K. Loyalka(Authors)
- 2014(Publication Date)
- CRC Press(Publisher)
568 550 Handbook of Alternative Fuel Technologies miles of rocks and metallic alloys at or near their melting temperatures. Geothermal resources range from shallow ground to hot rock and water several miles below the earth’s outer surface, and even farther down toward the earth’s core, in the region of extremely high temperatures of molten rock called magma . Geothermal energy, the second most abundant source of heat on earth after solar energy, is accessible using current technology and is concentrated in underground reservoirs, usually in the forms of steam, hot water, and hot rocks. The three appli-cable technology categories are geothermal heat pumps (GHPs), direct-use applica-tions, and electric power plants. GHPs use the earth’s surface as a heat sink and heat source for both heating and cooling. Direct-use applications utilize the naturally occurring geothermally heated water for heating. Electric power plants use electric turbines fed by geysers to generate electricity. As in solar energy, the utility of geo-thermal energy is hampered by the extent of its distribution over the earth’s surface in amounts that are often too small or too dispersed. 1 This is especially serious for the generation of electricity. The most obvious forms of geothermal energy are geysers , boiling pools of mud, fumaroles, and hot springs. However, a greater potential does exist in regions not yet recognized for their energy possibilities—they are hot dry rocks ( HDRs ). Besides the vast availability and the unique distribution pattern of these resources, geothermal energy is very clean and environmentally friendly. Geothermal energy generates no (or minimal) greenhouse gases because the conversion or utilization pro-cess does not involve any chemical reaction, in particular, combustion. Geothermal fields produce only about one-sixth of the carbon dioxide that a natural-gas-fueled power plant produces and very little, if any, of the nitrous oxide or sulfur-bearing gases.
eBook - ePubRenewable Energy and Sustainability
Prospects in the Developing Economies
- Imran Khan(Author)
- 2022(Publication Date)
- Elsevier(Publisher)
Chapter 9Geothermal energy in developing countries–The dilemma between renewable and nonrenewable
Nurdan Yildirima , Emin Selahattin Umduba Mechanical Engineering Department, Yasar University, Bornova, İzmir-Turkeyb Energy Systems Engineering Department, Yasar University, Bornova, İzmir-Turkey9.1 Introduction
The word geothermal is formed by the combination of the Greek words geo (earth) and therme (heat). Basically, geothermal energy, resulting from the molten interior of the earth and the decay of radioactive materials in underground rocks, is generally defined as the energy coming from the depths of the earth. The temperature at the center of the Earth, around 6500 km-depth, is about 6000°C and is almost the same as the surface temperature of the sun. Magma, rising in places on the buoyancy forces, pushes the plates towards the Earth's crust and in this way a large amount of heat has been emitted from the Earth's core for about 4.5 billion years. The temperature gradient of the Earth and the total heat flux from the Earth's interior are normally 2 to 3°C/100 m and around 80 mWth/m2 , respectively (Dumas, 2017 ). Since the radioactive processes in the core of the Earth are continuous, geothermal energy can be classified as a renewable energy source (G. Systems, 2016 ; Yildirim, 2010 ; Petroski, 2013 ; Miller, 2006 ).Rainwater and melted snow seepage into the ground with the help of faults and cracks in the earth, and then they are heated up to above boiling temperature such as 260°C or more by hot rocks (Nemzer, 2005 ). If hot rocks are permeable, the percolating surface waters naturally circulate back to the surface, returned as steam forming hot springs, geysers, and fumaroles. When the rocks are not permeable, the water is trapped by impermeable rocks, filling the rock pores and cracks, geothermal reservoir is formed (Burgess, 1989
eBook - ePub- W Shepherd, D W Shepherd(Authors)
- 2014(Publication Date)
- ICP(Publisher)
CHAPTER 7
GEOTHERMAL ENERGY
7.1.Physical Basis of Geothermal Energy
Geothermal energy is thermal energy stored in the sub-surface of the earth. It is not a renewable source because prolonged exploitation can exhaust a particular site. Nevertheless, the vast extent of energy potentially available is such that many references refer to it as if it was infinitely renewable. Energy is stored in natural underground reservoirs of steam and/or hot water, known as aquifers, and also in more solid “hot sediments” that are buried at depth or adjacent to hot spots.Heat energy flows outwards from within the earth at the average rate of 0.063W/m2 . The total outward flow amounts to 32 × 1012 W, as shown in Fig. 2.1 of Chapter 2 . It is of interest that the amount of interior heat flux flowing outwards is only about one-thousandth the value of the solar energy flux falling from space onto the same area [1 , 2 ]. The surface geothermal heat distribution is too small and too diffuse to be exploited, except in concentrated hot spots such as geysers or volcanoes.7.2.Geological Structure of the Earth
The geological structure of the earth is illustrated in Fig. 7.1 [3 ]. It is believed to approximate to five concentric spheres. From the outside proceeding inwards these are the atmosphere, crust, mantle, liquid outer core (magma) and solid inner core. As one proceeds inwards the temperature and density increase. For non-volcanic (i.e. non-seismic) areas the average geothermal gradient is between 17°C and 30°C per kilometre of depth (50°−87°F per mile). In volcanic areas the temperature gradient is much higher.The earth’s crust, composed of basalt, silicate rocks, is not of uniform thickness. Under the oceans the crust is about 15 km thick and consists of porous rock. Under the continental land masses the crust is about 35 km thick (Fig. 7.2 ) and the proportion of porous rock probably increases with depth. Between the continental land mass and the ocean, the continental shelf contains a great thickness of sedimentary rocks such as sandstone or limestone [4
eBook - ePubFlow and Heat Transfer in Geothermal Systems
Basic Equations for Describing and Modeling Geothermal Phenomena and Technologies
- Aniko Toth, Elemer Bobok(Authors)
- 2016(Publication Date)
- Elsevier(Publisher)
Chapter 1What Is Geothermal Energy?
Abstract
The knowledge and use of geothermal energy have a long history. The primary source of geothermal energy is the decay of radioactive elements. This energy is stored in the high temperature region of the Earth's crust, mantle, and core. From an engineering point of view, only the upper region of the crust has practical importance. Terrestrial heat-flow and geothermal gradient are the main parameters used to characterize a region's geothermal properties. These parameters correspond to the tectonic motion of the lithosphere plates. That geothermal phenomenon occurs most intensely at the boundaries of the lithosphere plates. Where subcrustal erosion and tension stresses have thinned the continental crust terrestrial heat-flow is also above average. A geothermal reservoir is that part of the Earth's crust from which internal energy content can be recovered with the help of some reservoir fluid: steam, hot water, or a mixture of both. When studying geothermal reservoirs, different reservoir types yield correspondingly different conceptual models.Keywords
EGS; Geothermal gradient; Geothermal reservoir; HDR; Heat conduction; History of geothermal use; Mantle flow; Plate tectonics; Terrestrial heat-flowOutline1.1 Introduction 1.2 The Nature and Origin of Geothermal Energy 1.3 Geothermal Reservoirs References1.1. Introduction
Geothermal energy is energy contained within the high temperature mass of the Earth's crust, mantle, and core. Since the Earth's interior is much hotter than its surface, energy flows continuously from the deep, hot interior up to the surface. This is the so-called terrestrial heat-flow. The temperature of the Earth's crust increases with depth in accordance with Fourier's law of heat conduction. Thus the energy content of a unit of mass also increases with depth.All of the Earth's crust contains geothermal energy, but geothermal energy can only be recovered by means of a suitable energy-bearing medium. To be practical, the energy-bearing media must be: hot enough (high-specific energy content), abundant enough, easily recoverable, inexpensive, manageable, and safe. Water satisfies these requirements perfectly. The specific heat of water is 4.187
eBook - PDFOcean Energies
Environmental, Economic and Technological Aspects of Alternative Power Sources
- R.H. Charlier, J.R. Justus(Authors)
- 1993(Publication Date)
- Elsevier Science(Publisher)
38 1 Chapter 9 GEOTHERMAL ENERGY ... there is some encouragement that in the reflection that Oceanography has usually only ruined the reputations of people who dared to speculate too little and thought on too small a change. She has smiled most benignly on those who backed the most daring and outraging possibility. The Great Ocean Business, Brenda Horsfield and Peter Bennet Stone GEOTHERMAL ENERGY A certain amount of thermal energy can be extracted from the earth and used economically to produce electricity. This has been done for some time, including by the United States. Geothermal resources are either submarginal or paramarginal: the first group includes resources whose recovery would cost more than twice as much as the price of other energy sources, and the second group those recoverable at a cost one to two times that price. Geothermal resources exist in hydrothermal convection systems, either vapor dominated or hot water systems; hot igneous systems, either partly molten or hot dry rocks; and conduction-dominated areas, like the Gulf of Mexico geopressured system (Fig. 9.1). BACKGROUND Geothermal means literally heat of the earth, a term coined from the Greek words yq (the earth) and Bt-ppos (heat). This source of heat was in use in ancient Rome to heat villas: the Romans tapped the naturally warm waters and established spas of hot mineral baths throughout their empire as far north as Bath (England) and Trier (Germany). They were not alone in tapping the medicinal properties of such hot springs, Babylonians and Greeks and later the Japanese, also did so. The use of thermal springs was somehow lost during subsequent eras, though in France such resorts as Dax, Ax-les-Thermes, Plombikres, and Chaudes-Aigues boast of continued usage. The Habsburg dynasty founded hydrothermal spas such as Marienbad in Bohemia (now Czechoslovakia), and the Hungarians sank a well to secure natural mineral waters.
eBook - PDF- Frank R. Spellman(Author)
- 2014(Publication Date)
- CRC Press(Publisher)
When collision or grinding occurs, it can create mountains, volcanoes, geysers, and earthquakes. Near the junction of these plates is where heat travels rapidly from the interior of the planet. 256 Environmental Impacts of Renewable Energy ENERGY CONVERSION The conversion of heat to electricity is common to most power plants. This is the case whether the energy source is coal, gas, nuclear power, wind power, solar power, water power, or Geothermal Power. Powering the nontransportation section of our economy is important, of course, so converting any fuel source to electrical power for industrial use is a prime objective in our constant and insatiable appetite for energy. It is tempting to think that we should focus solely on the production of elec-tricity to power not only our industries and homes but also everything else—one genie in one bottle to accomplish everything. Liquid fuels are the fuels of choice right now because they are accessible, available, and relatively inexpensive. Thus, although our ongoing research for other energy sources persists, we still do not have that absolute pressing need to come up with a liquid fuel replacement—at least not yet. Anyway, when our energy-needs focus shifts due to necessity, absolute or oth-erwise, geothermal energy will be available, and we need to continue our research in this important area. Energy conversion occurs routinely today, with a variety of types of energy, and geothermal conversion is nothing new; only the procedures and methodology differ. Geothermal energy conversion refers to the power-plant technology that converts the hot geothermal fluids into electric power. Even though Geothermal Power plants have much in common with traditional power-generating stations—turbines, genera-tors, heat exchangers, and other standard power-generating equipment—there are important differences between geothermal and other power-generating technologies.
eBook - PDFGeothermal energy
Utilization and technology
- Dickson Mary H., Fanelli Mario(Authors)
- 2003(Publication Date)
- UNESCO(Publisher)
In the next sixteen years, from 1984 to 2000, there was a further increase in the total of almost 150 per cent. Geothermal Power plays a fairly significant role in the energy balance of some areas, and of the developing countries in particular, as can be inferred from the data reported in Table 1.2, which shows the percentage of Geothermal Power with respect to total electric power installed in some of these countries, relative to 1998. As regards non-electric applications of geothermal energy, Table 1.3 gives the installed capacity (15,145 MW t ) and energy use (190,699 TJ/yr) worldwide for the year 2000. There are now fifty-eight countries reporting direct uses, compared to twenty-eight in 1995 and twenty-four in 1985. The data reported in this table are always difficult to collect and interpret, and should therefore be used with caution. The most common non-electric use worldwide (in terms of installed capacity) is heat pumps (34.80 per cent), followed by bathing (26.20 per cent), space heating (21.62 per cent), greenhouses (8.22 per cent), aquaculture (3.93 per cent), and industrial processes (3.13 per cent) (Lund and Freeston, 2001). 3 Geothermal Background 1.2 NATURE OF GEOTHERMAL RESOURCES 1.2.1 The Earth’s thermal engine The geothermal gradient expresses the increase in temperature with depth in the Earth’s crust. Down to the depths accessi-ble by drilling with modern technology (that is, over 10,000 m) the average geothermal gradient is about 2.5 to 3 °C/100 m.
eBook - PDF- Vaughn C. Nelson, Kenneth L. Starcher(Authors)
- 2015(Publication Date)
- CRC Press(Publisher)
254 Introduction to Renewable Energy images, search Macaques in Japan, http://www.google.com/imghp). Geothermal heat pumps (GHPs) use an electric heat pump to exchange heat with the ground or groundwater, instead of air, and can be used in almost all areas of the world. These systems for residences and larger buildings are now competing with conventional heating and cooling systems. 11.2 RESOURCE The geothermal resource for direct use and the generation of electricity is located along the tectonic plate boundaries and magma plumes, such as in Hawaii and Yellowstone. The size of the resource (Table 11.1) could supply all the primary energy Eurasian Eurasian Arabian East African Rift Indian African Australian Philippine Pacific Plate Scotia Antarctic Cocos Caribbean North American South American Nazca Volcano Juan de Fuca FIGURE 11.1 Tectonic plates of the Earth with volcanoes (historical). TABLE 11.1 Geothermal Energy Resource Base for the World and the United States Regime World Continental (109 BOE) United States (109 BOE) Magma systems 2,400,000 160,000 Crustal heat 79,000,000 2,300,000 Thermal aquifers 130 9 Source: Geothermal energy, www.geothermal.org/GeoEnergy.pdf. Note: BOE, barrel of oil equivalent. 255 Geothermal Energy for heat and electricity for the world. However, use is restricted due to location in relation to population, and of course, it is also restricted by economics. The total stored heat energy up to a depth of 5 km worldwide is estimated at 1.5 * 10 26 J, and if 1 % can be mined, the recoverable resource is on the order of 1.5 * 10 24 J, which is way larger than the world use of energy in 2013, 530 EJ. Regions and nations along the boundaries of the tectonic plates are using geother-mal energy and have maps of the resource. In Europe (Figure 11.2), Italy, Iceland, and Turkey are the major areas.
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