Encyclopedia of Global Resources part 132 pptx

1216 • Thailand Global Resources Thailand: Resources at a Glance Official name: Kingdom of Thailand Government: Constitutional monarchy Capital city: Bangkok Area: 198,131 mi 2 ; 513,120 km 2 Population (2009 est.): 65,905,410 Language: Thai Monetary unit: baht (THB) Economic summary: GDP composition by sector (2008 est.): agriculture, 11.6%; industry, 45.1%; services, 43.3% Natural resources: tin, rubber, natural gas, tungsten, tantalum, timber, lead, fish, gypsum, lignite, fluorite, arable land Land use (2005): arable land, 27.54%; permanent crops, 6.93%; other, 65.53% Industries: tourism, textiles and garments, agricultural processing, beverages, tobacco, cement, light manufacturing such as jewelry and electric appliances, computers and parts, integrated circuits, furniture, plastics, automobiles and automotive parts; world’s second largest tungsten producer and third largest tin producer Agricultural products: rice, cassava (tapioca), rubber, corn, sugarcane, coconuts, soybeans Exports (2008 est.): $174.8 billion Commodities exported: textiles and footwear, fishery products, rice, rubber, jewelry, automobiles, computers and electrical appliances Imports (2008 est.): $157.3 billion Commodities imported: capital goods, intermediate goods and raw materials, consumer goods, fuels Labor force (2008 est.): 37.78 million Labor force by occupation (2005 est.): agriculture, 42.6%; industry, 20.2%; services, 37.1% Energy resources: Electricity production (2007 est.): 148.4 billion kWh Electricity consumption (2007 est.): 138.6 billion kWh Electricity exports (2007 est.): 731 million kWh Electricity imports (2007 est.): 4.488 billion kWh Natural gas production (2007 est.): 25.4 billion m 3 Natural gas consumption (2007 est.): 35.3 billion m 3 Natural gas exports (2007 est.): 0 m 3 Natural gas imports (2007 est.): 9.8 billion m 3 Natural gas proved reserves ( Jan. 2008 est.): 331.2 billion m 3 Oil production (2007 est.): 348,600 bbl/day Oil imports (2005): 832,900 bbl/day Oil proved reserves ( Jan. 2008 est.): 176 million bbl Source: Data from The World Factbook 2009. Washington, D.C.: Central Intelligence Agency, 2009. Notes: Data are the most recent tracked by the CIA. Values are given in U.S. dollars. Abbreviations: bbl/day = barrels per day; GDP = gross domestic product; km 2 = square kilometers; kWh = kilowatt-hours; m 3 = cubic meters; mi 2 = square miles. China Bangkok Myanmar Thailand Cambodia Vietnam Laos Malaysia Indonesia Bay of Bengal Andaman Sea Gulf of Thailand South China Sea Indian Ocean increased 60 percent, earning $2.8 billion. Three years later, Thailand produced 2.7 million metric tons of that resource, andindustry representativesexpected yields to expand2.2 percent annually afterward. That year, Thailand exported 2.5 million metric tons of natural rubber worth $5.41 billion to the United States, Japan, China, and other markets. Occasionally, weather changes caused by El Niño have threatened successful rubber harvests and that industry’s success in Thailand. Synthetic rubber has competed against natural rubber for markets, impact- ing Thailand’s rubber industry, which has suffered declining prices and lost income. The Thai government has encouraged rubber farmers to continue cul- tivating rubber plantations during economic crises, such as the international recession in 2008, which affected automobile production, reducing demand for rubber tires. Tin Thailand has produced the third most tin internationally since 2002, competing with neighboring Malaysia and Indonesia, both of which have ample tin resources. Tindeposits stretchfrom Thailand’speninsula, which has the largest reserves, to smaller amounts in northern provinces along the Myanmar (Burma) border. Thais have mined tin ore for several centuries. In addition to their location in land sites, tin ore deposits are often found in sea- and riverbeds. Islands near Phangnga Province have large tin deposits. The retrieval of tin from seabed deposits requires specialized technology, such as dredges and suction devices on boats. Because of the expenses involved in extracting tin, mining companies that can afford the necessary equipment and employ experienced divers dominate offshore tin mining. In addition to Thai mining businesses, many foreign companies invest in extracting tin resources located close to Thailand’s coasts. By 1963, Thailand Smelting and Refining Com- pany Ltd. (THAISARCO) operated a tin smelter at Phuket. During the 1980’s, Thailand produced more than 27,000 tons of tin yearly in addition to unreported tin exports shipped clandestinely to markets in an attempt to avoid paying taxes and royalties to the government. During the following decades, tin exports consistently generated foreign income for Thailand, with only a small portion of that resource being used domestically. By 2000, approximately 70 percent of Thai tin and related materials, such as slag and tanta - lum, were that country’s leading global exports. Thai- land exported tin worth 6 billion baht (roughly $162 million) in 2006. In 2007, tin prices reached $15,000 per metric ton; the rate of government royalties and the willingness of the Department of Mineral Re- sources to adjust percentages the government re- ceived affected the interest of mining companies and investors in that resource. Tantalum Tantalum represents Thailand’s most controversial resource. Thais have resisted tantalum refinery methods, which they consider detrimental to environmental and economic quality. Tantalum is often used in computing, electronics, and aerospace technology. In 1985, the Thailand Tantalum Industry Corporation, with a desire to profit from this tin by-product, started construction of a $46 million tantalum refinery near Global Resources Thailand • 1217 A worker in a Thai rubber factory holds a container of latex. Rubber is a major natural resource for Thailand. (Sukree Sukplang/ Reuters/Landov) houses and hotels on Phuket, a popular Thai island that generates income from tourism and fisheries. Many people in Phuket were already angry that tin mining and related industrial processes had detri- mentally impacted their community, particularly in terms of the environment, which was crucial to attracting tourists and maintaining fish health (fishing provides many residents funds). They voiced their worries about disposal of hydrofluoric acid incorpo- rated in Thailand Tantalum Industry Corporation’s procedures. On June 1, 1986, fifty thousand citizens, represent- ing the Committee to Coordinate Action Against Pol- lution, protested publicly and signed petitions, de- manding the Thai government intervene to stop the refinery. Thai industry minister Chirayu Isarangkun na Ayutthaya traveled to Phuket on June 23 but left quickly, frightened by the enraged crowd, which burned the refinery and kept firefighters away. Re- sponding to this action, the Thai government passed the National Environmental Quality Act to fund regu- lating industries, particularly those refiningtantalum, and to remove industrial materials contaminating the environment. By August, 1992, the Thailand Tanta- lum Industry Corporation had built another tantalum refinery at Map Tha Phut, an industrial site, and stated hydrofluoric acid would not be released out- side the factory. Achieving rates of 272,000 kilograms annually, that company often produced 40 percent of tantalum globally, the most in the world. Thailand hosted the World Tantalum Conference in 1992. Rice In the first decade of the twenty-first century, Thai- land exported more rice than any other country in the world. Prior to the 2008 economic crisis, Thailand exported more than 5.9 million metric tons of rice every year. Encouraged by King Bhumibol Adulyadej, who promotes agriculture, Thai farmers cultivate this lucrative crop on large areas (28 percent of the country) of Thailand’s arable land. Thailand’s unique jasmine rice attracts foreign buyers willing to pay higher prices for this delicacy. The Thai government started emphasizing jasmine rice in the 1980’s in an attempt to surpass other exporting nations. Thai exports of jasmine rice accumu- lated $48 million dollars during 1988. Prices for Thai jasmine rice exports rose 44.4 percent within two decades, with yields increasing approximately 2.5 per - cent annually. Competitors attempt to grow and market jasmine rice but have been unable to achieve the quality and quantity Thai rice producers have achieved. Thailand’s greatest challengers for rice- exporting leadership include U.S. long-grain rice and Pakistan’s basmati rice. Vietnam poses regional com- petition for rice production. In 2004, Thailand produced 9.18 million metric tons of rice worth $2.73 billion. A 2005 drought low- ered rice exports, with jasmine rice selling for about $400 per metric ton and pathumthani rice receiving $275 to $450 per metric ton. The global economic crisis in 2008 impacted Thailand’s rice exports despite food shortages increasing demand. Rice production in Nakhon Sawan Province decreased by 25 percent. In 2009, the Bangkok Post reported Thailand’s rice exports had decreased by 15.9 percent, with the country exporting only 666,688 metric tons of rice, worth $406 million to international markets. Payment of European Union tariffs, approximately $160 per metric ton, which many Asian countries are not required to pay, reduced Thailand’s profits. Lignite Since the 1960’s, the Electricity Generating Authority of Thailand (EGAT) has extracted lignite, a form of coal, from the Mae Moh Lignite Mine in the country’s northern Lampang Province as an energy resource to fuel the country’s biggest power plant. Geologists stated the coal deposits beneath the Mae Moh mine, which encompasses 32 square kilometers, total 630 million metric tons, placing it among the region’s biggest mines. This mine annually produced 2.5 million metric tons of lignite at its peak. Wanting to reduce Thailand’s reliance on imported oil, government officials planned additional development of Thai resources to generate energy. The Second Mae Moh Lignite Project resulted in more lignite extraction at that mine, attaining 4.5 million metric tons produced yearly. Thailand’s second lignite mine, in Krabi Province on Thailand’s peninsula, produces about 250,000 metric tons of lignite annually. Lignite mining in Thailand has caused problems. Approximately thirty thousand citizens were removed from lands in the Mae Moh valley in order to facilitate construction and operation of the Mae Moh mine and power plant. The mining process released pollutants, especially dust and sulfur dioxide emissions, into the environment, contaminating water and air sources and damaging people’s health. Agricultural resources, including soil and crops, were severely damaged. 1218 • Thailand Global Resources In the early twenty-first century, the Mae Moh power plant provided Thailand with electricity but had the undesirable distinction of being Southeast Asia’slargest producer of sulfur gas. Villagers pursued litigation against EGAT. In March, 2009, a Chiang Mai court demanded that EGAT provide $7,000 per Thai whom lignite mining and power generation had harmed physically and economically. EGAT also was required to pay for villagers to move to land located at a safe distance from the power plant and to improve the mine’s environment by planting trees. Natural Gas Thailand has sought to develop such indigenous energy resources as natural gas because the country did not produce sufficient oil to meet domestic demand and was consistently among the top oil importers in Southeast Asia. During the 1970’s, Thailand identi- fied several Gulf of Thailand natural gas fields. The field near Sattahip contained 40 billion cubic meters of known natural gas reserves and possibly another 6.2 billion cubic meters. Another field, located 170 kilometers south of Sattahip, held 3 billion cubic meters of natural gas with potentially 127 billion cubic meters more. Other fields contributed to more than 300 billion cubic meters of Thai natural gas reserves. In the early 1980’s, the Petroleum Authority of Thailand (PTT) and the Ministry of Industry oversaw pipeline construction near Map Tha Phut, extend- ing south 425 kilometers in the gulf to a natural gas field. Other pipelines on land transported natural gas to thermal power plants and industries in Bang- kok and Bang Pakong. The Erawan field provided natural gas through pipelines to several gas and power plant sites, including ones in Rayong, Samut Prakan Province, and the Khanom district in Nakhon Si Thammarat Province. The Bongkot natural gas field became Thailand’s biggest source of that resource, attracting such international companies as Chevron. That company extracts natural gas from twenty-two Thai fields, producing 70 percent of that resource in Thailand. In 2008, the Gulf of Thailand’s Arthit and Block A- 18 fields began contributing 20 million cubic meters of natural gas daily to boost yields. Oil and Gas Journal projected that extraction from more Gulf of Thailand natural gas fields will enable Thailand to acquire sufficient amounts of that resource to exceed demand. Officials urged Thai motorists to use natural gas as a fuel instead of oil. Other Resources Thailand has numerous mineral resources with vary- ing production levels and contributions to the global economy. Exports of Thai feldspar have ranked high internationally, behind Italy and Turkey, with one million metric tons produced in 2006, approximately 7.5 percent of the global exports. A zinc deposit located in Tak Province at Mae Sot held 3.2 million metric tons. Thailand ranked eighth in the world for gypsum exports in 2001, producing 8.6 million metric tons of gypsum in 2007. Finally, Thailand’s Ministry of En- ergy has encouraged companies such as Solartron to manufacture sufficient amounts of photovoltaic cells to export that commodity. Fish comprise 10 percent of Thailand’s exports, especially prawns and tuna. Thailand has regularly ranked third in deep-sea fishing yields among Asian countries. Thailand’s agricultural resources, rang- ing from crops—including sugarcane, coconuts, and pineapples—to forestry, have consistently earned Thai- land global rankings near the top ten for exports. Thai- land also exports cassava, sold as tapioca, globally. Thailand has gained income from luxury resources. In 2006, Thailand earned $14.5 million from silk exports. Although Indiaand China dominateinterna- tional silk trade, many consumers prefer Thai silk, produced from silkworms cultivated on mulberry groves in Isan. Thailand exports orchids to global markets. Consistent consumer demand, despite economic recessions, enables Thailand to acquire more than $100 billion yearly from orchid exports. Gem- stones contribute to Thailand’s export gains, with sap- phires mined from Kanchanaburi Province and ru- bies extracted from Chanthaburi and Trat provinces. Mines in Lamphun and Chiang Mai provinces extract minerals, including some uranium, from sizable fluorite deposits. Elizabeth D. Schafer Further Reading “Amanta Revives Thai Tungsten.” Mining Journal (June, 2008): 7. Douangngeune, Bounlouane, Yujiro Hayami, and Yo- shihisa Godo. “Education and Natural Resources in Economic Development: Thailand Compared with Japan and Korea.” Journal of Asian Economics 16, no. 2 (April, 2005): 179-204. Hirsch, Philip, ed. Seeing Forests for Trees: Environment and Environmentalism in Thailand. Chiang Mai, Thailand: Silkworm Books, 1998. Global Resources Thailand • 1219 Keeratipipatpong, Walailak. “Thai Orchid Exports Remain Resilient.” Bangkok Post, June 17, 2009. Rahman, Sanzidur, Aree Wiboonpongse, Songsak Sriboonchitta, and Yaovarate Chaovanapoonphol. “Production Efficiency of Jasmine Rice Producers in Northern and Northeastern Thailand.” Journal of Agricultural Economics 60, no. 2 (2009): 419-435. Web Sites Amanta Resources Ltd. http://www.amantaresources.com Thailand Ministry of Natural Resources and Environment Department of Mineral Resources http://www.dmr.go.th/dmr_data/eng/ indexeng.htm Thailand Smelting and Refining Company Ltd. http://www.thaisarco.com See also: Agricultural products; Agriculture industry; El Niño and La Niña; Oil and natural gas distribution; Rice; Rubber, natural; Tin; Tungsten. Thallium Category: Mineral and other nonliving resources Where Found Thallium is widely distributed in the Earth’s crust in small amounts. A few minerals exist that contain up to 60 percentthallium, but these are extremelyrare. The most important sources of thallium are zinc and lead ores. Primary Uses Thallium compounds are used in very small amounts for special applications in electronics and glass- making. Thallium was used previously in pesticides. Technical Definition Thallium (abbreviated Tl), atomic number 81, be- longs to Group IIIA of the periodic table of the elements and resembles lead in its chemical and physical properties. It has two naturally occurring isotopes and an average atomic weight of 204.37. Pure thallium is a soft, dense, shiny metal that dulls to a blue-gray tinge when exposed to air. Its density is 11.85 grams per cu - bic centimeter; it has a melting point of 303.5° Celsius and a boiling point of 1,457° Celsius. Description, Distribution, and Forms Thallium is a fairly rare element resembling lead. It is mostly obtained as a by-product of the extraction of lead or zinc from sulfide ores or from copper smelting. Most of this production takes place in the United States (recovery from flue dust and smelters), Canada, and Europe. Once used in pesticides, thallium is now used to a limited extent in manufacturing photoelectric devices and in making special kinds of optical equipment. History Thallium was discovered in 1861 by the British chem- ist and physicist Sir William Crookes. Its first important industrial use was as a rat poison and insecticide in the form of thallium sulfate, first used in Germany in the 1920’s. In the 1960’s, thallium compounds fell out of use for this purpose. Obtaining Thallium Thallium is usually obtained from the sulfide ores of zinc and lead. When these ores are heated to extract the zinc or lead, dust and gas that contain thallium compounds, as well as compounds of elements such as cadmium, indium, selenium, and tellurium, are released. Thallium compounds are separated from the other compounds by a variety of chemical processes. In general, these methods involve forming compounds of thallium that have higher or lower sol- ubilities in certain liquids than the equivalent compounds of the other elements. Crystallization removes the least soluble compound. Free thallium may be obtained from the compound by electrolysis, resulting in a powder. It may then be transformed into metallic form by compressing it, heating it in the absence of oxygen, and casting it into molds. Uses of Thallium Thallium is not a major resource in manufacturing, but it has a few special uses. Thallium sulfide may be used to make photoelectric cells that are highly sensi- tive to infrared light. Thallium bromide and thallium iodide can be used to produce crystals that transmit infrared light. These crystals may then be used to make lenses, windows, and prisms for use in infrared optical systems. Thallium oxide may be used to make special kinds of glass or to add color to artificial gems. 1220 • Thallium Global Resources Thallium-barium-calcium-copper oxide high- temperature superconductors are used in wireless communication devices. Sodium iodide crystals doped with thallium are used in scintillometers for the detec- tion of gamma rays. Thallium increases the refractive index and density of glass; it is employed as a catalyst for the synthesis of organic compounds; it is used in high-density liquids that are employed in mineral- separation methods; it is also alloyed with mercury to measure low temperature. Finally, thallium 201, a radioactive isotope, is used in cardiovascular imaging. Thallium compounds are often toxic, as shown by their former use in pesticides. Thallium poisoning is rare but can be fatal. Symptoms of thallium toxicity include rapid hair loss and disorders of the digestive and nervous systems. Rose Secrest Web Site WebElements Thallium: the Essentials http://www.webelements.com/thallium/ See also: Lead; Metals and metallurgy; Pesticides and pest control; Zinc. Thermal pollution and thermal pollution control Category: Pollution and waste disposal Thermoelectric power plants remove large quantities of water from the environment, use it to condense steam exiting a turbine, and return warmer water. Although the water is heated only slightly, there are environmental consequences. Definition Thermal pollution is waste heat that has been dumped into an aquatic environment. The main sources of thermal pollution are fossil-fuel and nuclear power plants. Overview The oxygen content of the heated water, critical for most marine life, decreases as the temperature in - creases, while concurrently plankton multiply more rapidly, putting a further demand on the available oxygen. Since fish are cold-blooded and cannot maintain a constant body temperature, their metabolic rate increases with temperature: More oxygen is needed, and less is available. Also, the toxicity of chemical pollutants present in a lake or river increases with temperature. Extra heat in thewater can also raise the temperature beyond the lethal temperature for fish. Cold-water species such as salmon and trout die quickly when the water temperature reaches 26° Celsius. Although fish can adapt to warmer water if the change occurs slowly, the rapid changes that occur when power plants shut down for maintenance are usually fatal. Furthermore, warm water can block cold-water species from reaching their spawning areas, and entire food chains can be disrupted when higher temperatures alter a local eco- logical balance. Thermal pollution can be controlled either by using the waste heat or by alleviating it through other means when it cannot be used. Waste heat could be utilized to irrigate fields in cold, dry climates so as to extend the growing season. Waste heat can preheat salt waterfor distillation in coastalregions where fresh water is scarce, such as in Southern California. A large pond could be used to contain the heat, and the pond could be stocked with catfish, a source of food, which thrive in 34° Celsius water. Combining a sewage treat- ment plant with an electric power plant, the waste heat could be employed to help evaporate water from treated sewage. In winter, waste heat could be used to heat factories located near the power plant. Finally, rivers suchas the St. Lawrencethat often freezein winter perhaps could, with a sufficient number of power plants along its bank, be kept open for navigation. There are two methods for alleviating thermal pollution when no useful means of using the heat can be found. The simpler method is a cooling pond. The warmed water flows into a large artificial pond, where it releases its heat into the atmosphere. After cooling, the water may be reused or flow back into a river. Al- though relatively inexpensive to construct and maintain, this method requires a large amount of land— approximately 800 hectares for a typical small power plant producing 1,000 megawatts. Obviously this is not feasible in a densely populated region. The main way that thermal pollution is alleviated is by means of the cooling tower, essentially a very large radiator. The heated water flows through finned tubes, transferring its heat to the atmosphere. If the system Global Resources Thermal pollution and thermal pollution control • 1221 is closed, no water is lost through evaporation. For a typical small, 1,000-megawatt plant, at least one tower 76 meters in diameter and 98 meters high is required. Although not much land area is covered, the towers are much more expensive than cooling ponds. Each tower adds approximately 10 percent to the cost of constructing the power plant, which causes electricity rates to be about 5 percent higher. George R. Plitnik See also: Coal; Cogeneration; Nuclear energy; Water pollution and water pollution control. Third World countries. See Developing countries Thorium Category: Mineral and other nonliving resources Where Found Thorium occurs in various minerals that contain uranium or rare earth elements. The most important source of thorium is monazite, which is usually found in sand. Sand containing monazite is found in India, Brazil, Australia, Madagascar, Sri Lanka, South Africa, and Canada. In the United States, thorium is found in Idaho, Florida, Michigan, California, Colorado, North Carolina, and South Carolina. Primary Uses Thorium is mostly used in the form of thorium 232. This can be used to produce uranium 233 for nuclear reactors. Technical Definition Thorium (abbreviated Th), atomic number 90, be- longs to the actinide series of the periodic table of the elements and resembles uranium in its chemical and physical properties. All thorium isotopes are radioactive; thorium 232 dominates because it has a half- life of about fourteen billion years. Thorium has an atomic weight of 232.038. Pure thorium is a silver- white metal that turns gray or black when exposed to air. Its density is 11.7 grams per cubic centimeter; it has a melting point of about 1,700° Celsius and a boil - ing point of about 4,000° Celsius. (Exact figures can - not be given because these values are greatly changed by impurities.) Description, Distribution, and Forms Thorium is a fairly rare radioactive element resembling uranium. It is mostly obtained along with rare earth elements in the processing of monazite. Tho- rium serves as an indirect source of nuclear power because it can be changed into uranium. History Thorium was discovered in 1828 by the Swedish chem- ist Jöns Jacob Berzelius. Its radioactive nature was discovered in 1898. In the late nineteenth century and early twentieth century, thorium was mostly used in mantles for incandescent gaslights because it gave off a bright white light when heated. Obtaining Thorium Thorium is usually obtained from monazite. First the monazite is finely ground and mixed with hot sulfuric acid or hot sodium hydroxide to separate thorium and rare earth elements from the other substances found in monazite. Thorium compounds are then obtained from this mixture by a variety of chemical re- actions. In general, these methods depend on the fact that certain thorium compounds have different solu- bilities from similar compounds of the rare earth elements in certain solvents. Free thorium may be obtained by treating thorium oxide with calcium at about 950° Celsius. It may also be obtained by the electrolysis of thorium chloride. The thorium powder obtained by these methods may be transformed into thorium metal by compressing it and heating it in a vacuum. Uses of Thorium In a nuclear reactor thorium 232 can be transformed into uranium 233, which can undergo fission to re- lease nuclear energy. Thorium is also used to strengthen magnesium alloys, to make photoelectric cells, as a catalyst, in welding electrodes, and in high- temperature ceramics. Because thorium is radioactive, it poses a health hazard. Although thorium 232 is not particularly dan- gerous on its own, one of the substances it changes into as it decays, radon 220, is hazardous because it is a gas and may enter the lungs. Because of its radioactiv - ity, the use of thorium products has decreased. Rose Secrest 1222 • Thorium Global Resources Web Site U.S. Geological Survey Mineral Information: Thorium Statistics and Information http://minerals.usgs.gov/minerals/pubs/ commodity/thorium/ See also: Metals and metallurgy; Nuclear energy; Rare earth elements; Uranium. Three Gorges Dam Category: Obtaining and using resources The Three Gorges Dam, in addition to being one of the largest dams ever built, is perhaps the most public example of the conflict between resource manage- ment benefits and the environmental and societal costs. Definition The Three Gorges Dam lies on the Chang River (also known as the Yangtze River) in China. It is designed primarily to provide flood control, electricity, and reliable water resources. In pro- viding these resource benefits, however, construction of the dam also damaged the existing ecology, forced people be relocated, and flooded cultural sites. Overview The Three Gorges Dam was proposed by Sun Yat-sen in 1919 and later supported by Mao Zedong. Plans for the dam were approved in 1992, and construction began in 1994. In 2006, the 185-meter-tall and 2.3-kilometer-long dam was completed. The reservoir behind the dam extends 660 kilometers to Chongqing and cov- ers an area of approximately 1,050 square kilometers. The dam cost approximately $30 billion, with an additional $22 billion spent to relocate people living in the flooded area of the reservoir, $2 billion to stabilize slopes near the reservoir, and $5 billion to improve water quality in the reservoir. A benefit of the Three Gorges Dam is flood control. The Chang River has flooded approxi - mately one thousand times in the last two thou - sand years, including five major floods in the twenti - eth century that killed thousands to millions of people. The Three Gorges Dam is designed to dramatically reduce the possibility of floods. The dam also produces more electricity than any other dam in the world. At full capacity, the dam is expected to generate more than 80 terrawatt-hours per year in electricity. This energy will help fuel growth and development in China, while contributing to China’s goal of meeting up to 15 percent of its energy needs from renewable sources by 2020. The large volume of water stored in the reservoir, approximately 40 cubic kilometers, will provide reliable water resources for nearby industry, agriculture, and municipalities. Finally, because the reservoir widens and deepens the Chang River for such a long distance, large vessel navigation is now possible from Shanghai to Chongqing. Global Resources Three Gorges Dam • 1223 As of 2010, the controversial Three Gorges Dam in China was the largest hydropower station in the world. (Zheng Jiayu/Xinhua/Landov) These benefits do not come without significant costs. Approximately 1.2 million people had to be relocated, which is the largest population resettlement in peacetime history. In addition, it was announced that between 4 and 16 million additional people living in the area might need to be relocated in the future. The decreased freshwater outflow from the dam re- sults in more saline conditions farther downstream, which has impacts on wildlife and on diseases, such as schistosomiasis. The heavily fished Chang River has seen a steep decline in its total catch since the reservoir started filling, although it is uncertain how much of this decline is because of the dam. Also, it ispossible that the Three Gorges Dam will result in the extinc- tion of the river dolphin (baiji) and the finless por- poise (jiangzhu). Finally, it is uncertain how quickly sediment will build up behind the dam and how this loss of sediment from downstream will erode the important Chang Delta islands. With the dam in place, China has spent billions of dollars to monitor its environmental impact. Thomas R. MacDonald See also: Central Arizona Project; China; Dams; Deltas; Energy politics; Floods and flood control; Hydroenergy; Irrigation; Los Angeles Aqueduct; Streams and rivers; Water; Water supply systems. Three Mile Island nuclear accident Category: Historical events and movements On March 28, 1979, a serious accident at Three Mile Island nuclear reactor number two resulted in the re- lease of a relatively small amount of radioactivity into the surrounding area. Fearing that the accident might be worse, 100,000 residents fled. The legacy of Three Mile Island was to stop the expansion of nuclear power generation in the United States. Background Near Middletown, Pennsylvania, there is an island in the Susquehanna River that is almost exactly 3 miles (4.8 kilometers) long. A consortium of electric power companies built two pressurized-water nuclear power plants on this island. Safety precautions included en - closing the reactor core in a steel containment vessel 22 centimeters thick. This vessel and the reactor cool - ing system were then enclosed inside a large contain - ment building having walls of heavily reinforced con- crete 1.2 meters thick. When an accident occurred in March of 1979, the safety precautions worked. The accident was caused by a combination of hu- man error and mechanical failure. As a result, the core overheated and released radioactivity into the cooling water. Subsequently, many thousands of liters of contaminated water flowed into the containment building and into an auxiliary building. Alarge hydro- gen gas bubble formed at the top of the core containment vessel. Fearing that the bubble might explode and breach the containment vessel, authorities con- sidered evacuation. Reaction and Evacuation As news of the accident was broadcast, the local citizens wereunderstandably apprehensive. Although no evacuation was ordered, Richard Thornburg, gover- nor of Pennsylvania, prudently advised a limited evacuation of those who were most susceptible to harm by radiation: preschool-aged children and pregnant women. Out of prudence or fear, more than 100,000 people evacuated. For a brief period the area near Three Mile Island became a ghost town inhabited mainly by monitoring teams and news reporters. Over the next several days, there were both planned and unplanned releases of radioactivity into the atmosphere as the reactor core was cooled and the hydro- gen bubble removed. These releases were carefully monitored. Background radiation near Three Mile Is- land temporarily increased by 10 percent, which sta- tistically translates into a possible increase in cancer fatalities of 0.01 percent, a rate sufficiently small that it is likely that no one was harmed. (The probability of someone in the United States dying of cancer ranges between 15 and 20 percent. Ignoring the body’s abil- ity to repair itself and assuming that small radiation doses are harmful in the same proportion as large doses are known to be, background radiation from natural sources might increase cancer fatalities by 0.1 percent.) Impact of the Accident As a resultof the accident, changes were made. For example, within minutes of the initial coolant failure, a confusing array of more than one hundred lights and alarms clamored for attention with no obvious order of priority. This situation was rectified. Furthermore, reactor operators were subsequently given proper 1224 • Three Mile Island nuclear accident Global Resources training in emergency procedures. Safety oversight procedures also were strengthened. Spurred on by several political figures, antinuclear rallies exploded across the country. Antinuclear senti- ment became so strong in the United States that no new nuclear plants were ordered after the accident, and fifty-nine reactors that had been previously ordered were canceled. Unit two of Three Mile Island was not repaired. It underwent an eleven-year cleanup process and was shut down. The current owner of the facility continues to maintain Unit two in this shut- down state. It will not be decommissioned until Unit one is decommissioned. In 2009, the Nuclear Regula- tory Commission extended that date to 2034. Charles W. Rogers See also: Chernobyl nuclear accident; Isotopes, radioactive; Nuclear energy; Nuclear Regulatory Com- mission. Tidal energy Category: Energy resources Tidal energy utilizes the tides to create electricity by trapping seawater at the extremes of high and low tide and then releasing it through turbines. Although a potentially large source of power, it is most economically feasible where the tides average at least 4.5 meters and a narrow inlet encloses a large bay. The world’s first tidal electric generating station, built at the Rance estuary off the northwest coast of France, began operat- ing in 1966. Background The ebb and flow of the tides have long captured the imagination of poets, while the possibility of har- nessing this energy has been equally intriguing to technically inclined people. Mills powered by tidal motion were used almost continuously from the twelfth through the nineteenth centuries in England. In the seventeenth century, this technology was imported to New England. A tidal water pump installed under the London Bridge in 1580 operated success- fully for two and one-half centuries, and a tidal-powered sewage pump was used in Hamburg, Germany, until 1880. These systems were eventually superseded by more convenient electric pumps. Not until the 1950’sdid a renewed interest in tidal power develop as an offshoot of the search for environmentally benign sources of electric power. Extent of Tidal Power There are two high and two low tides every day. Thus, water may be trapped on one side or the other of a dam four times a day. The water released after the tide changes may be used to turn a turbine connected to a generator, thus producing electricity. If, for example, a tidal lake 3.2 kilometers by 16 kilometers is dammed, and the trapped water has a height of 1.5 meters (the average height of the tides), a maximum of 8 megawatts of electricity can be generated. By way of comparison, an average fossil-fuel plant generates at least1,000 megawatts. In many regions of the world, however, the tides are considerably higher—for example, in the Bay of Fundy, Canada, where the tides average 12 meters. Over the entire globe, the total energy dissipated in tidal flow is about 3 million megawatts. Assuming that approximately one-third of this is potentially available power, and further assuming that the con- version efficiency to electricity is about 20 percent, the maximum power available is 200,000 megawatts, about one-fifth the present world power demand. If one limits the consideration of tidal power generating stations to the places with convenient natural bays and/or abnormally high tides, the world total drops to 15,000 megawatts. The Rance Estuary Project Although many nations had an interest in developing tidal power plants, France solved the technical problems to construct the world’s first large-scale tidal generating station. Located at the mouth of Brittany’s Rance River estuary, this 240-megawatt plant was constructed at a cost considerably less than that of a con- ventional hydroelectric plant of comparable power. The location was chosen for two reasons: The average fluctuation of the tides is 8.8 meters, and, by damming the narrow inlet, a large volume of water could be trapped in the 14.5-square-kilometer estuary. To trap the water at the extremes of high and low tide, a dam 731 meters long was constructed across the Rance River, 3.2 kilometers upstream from where the river separates the towns of Dinard and St. Malo. The power-producing turbines are located under the central half of the dam. All tidal power-generating plants must contend with two problems: First, the Global Resources Tidal energy • 1225 . 1216 • Thailand Global Resources Thailand: Resources at a Glance Official name: Kingdom of Thailand Government: Constitutional monarchy Capital city:. metric ton; the rate of government royalties and the willingness of the Department of Mineral Re- sources to adjust percentages the government re- ceived affected the interest of mining companies. site, and stated hydrofluoric acid would not be released out- side the factory. Achieving rates of 272,000 kilograms annually, that company often produced 40 percent of tantalum globally, the most

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