Energy from fossil fuels (coal, natural gas, and oil) was in abundance and had essentially displaced wind power. The Atomic Energy Act of 1954 allowed private companies to develop nuclear energy for peaceful purposes. However, Europe was developing more wind-power technologies. For instance, from 1956 to 1957 in Denmark, Johannes Juul built the world’s first alternating current (AC) wind turbine, the very effi- cient Gedser wind turbine. The 1973 oil crisis, the en- vironmental movement, and the dangers of atomic energy led to renewed interest in wind energy, which is a renewable energy source. Electricity generated by renewable energy sources (solar, wind, hydro, geo- thermal, andbiomassenergy) is called “green” power. During the 1990’s, wind power was one of the fastest- growing sources of energy. Wind Energy Technology When the Sun warms areas of the Earth at different rates and the various surfaces absorb or reflect the ra - diation differently, there are differences in air pres - sure. As hot air rises, cooler air comes in to replace it. Wind, or air in motion, is the result. Air has mass, and moving air contains kinetic energy, the energy of that motion. Windmills convert wind energy into mechanical power or electricity. The modern electricitywindmills are called wind turbines or wind generators. In the wind turbine, wind turns two or three propeller-like rotor blades, which are the sails of the system. When the blades move, energy is transferred to the rotor. The wind shaft is connected to the rotor’s center, so both therotor and shaft spin. The rotational energy is thus transferred to the shaft, which spins an electrical generator at the other end. The ability to generate electricity is measured in units of power called watts. A kilowatt represents 1,000 watts, a megawatt is 1 million watts, and a gigawatt rep- resents 1 billion watts. Electricity consumption and production are described in kilowatt-hours. Multi- plying the number of kilowatts by the number of hours equals the kilowatt-hours. One kilowatt-hour equals the energy of one kilowatt produced or used for a period of one hour. 1346 • Wind energy Global Resources The Green Mountain Energy Wind Farm at Brazos in Texas was completed in 2003 and contains 160 wind turbines. The turbine’s size and the speed of the wind through the rotor determine the output of the tur- bine. As of 2009, the world’s largest turbine was the Enercon E-126, the firstwind turbine with 6-megawatt rated power. Wind turbines can generate electric- ity for an individual building or for widespread dis- tribution by connecting to an electricity grid or net- work. Wind Farms A wind farm or wind power plant is a group of large wind turbines (660 kilowatts and up) installed in the same location to jointly capture wind and pro- duce electricity. There can be up to about one hun- dred individual modules or turbines sited far apart and covering an extended area of hundreds of square kilometers. Turbines can be added as the need arises. Individual modules connect with a medium-voltage (usually 34.5-kilovolt) power collection system. Then a substation transformer increases the medium voltage of electrical current for connection with a high-voltage transmission system. Wind farms are best located in areas with consistent, strong, and unob- structed winds, such as high plains, mountain passes, and coastlines. In rural, agricultural areas, the land between the turbines can still be used for farming. As of 2009, the world’s second largest onshore wind farm was Florida Power and Light’s Horse Hol- low Wind Energy Center in Taylor and Nolan coun- ties, Texas. Completed in 2006, Horse Hollow has 421 turbines and delivers 735 megawatts of electricityatits peak. The world’s largest wind farm, as of October, 2009, was Roscoe Wind Farm in Texas,designed to de- liver 781.5 megawatts from 627 turbines. In 2008, T. Boone Pickens’s company, Mesa Power, placed a $2 billion order with General Electric (GE) for 667 wind turbines to be delivered in 2010 and 2011. Pickens, the legendary oil executive and energy investor, planned to build the world’s largest wind farm in Texas. He also created the Pickens Plan, which promotes generating up to 22 percent of the nation’s electricity from wind,thus freeing up the nat- ural gas supply to be used as transportation fuel and reducing foreign oil dependence. Wind farms can also be sited offshore in the shal- low waters of the oceans in order to capture the stron- ger winds. As of 2009, the world’s biggest offshore wind farm was the Lynn and Inner Dowsing Wind Farm near Skegness, Lincolnshire, England. Each of the fifty-four 3.6-megawatt turbines sits on a pylon driven into the shallow seabed and turns a hub that is more than 80 meters above sea level. As of 2009, plans existed for even larger offshore farms. When completed, Horns Rev 2 wind farm, sited in the North Sea between 30and40 kilometers west of the westernmost tip of Denmark, would become the world’s biggest offshore wind farm, delivering 209 megawatts from ninety-five turbines, at a cost of about $670 million. The 1,000-megawatt London Array in the outer Thames Estuary, one of the three strategic areas the United Kingdomgovernment hasidentified for offshore wind farm development, was scheduled for completion in the early 2010’s. In 2001, the Cape Wind Project was formally pro- posed. The proposed $1 billion farm would cover 38.6 square kilometers on Horseshoe Shoal in Nantucket, 8 kilometers off Cape Cod in Massachusetts. This loca- tion is one of the largest offshore areas with shallow water, which is very cost-effective because wind turbine foundation costs rise with increasing water depth and wave height. The farm’s 130 wind turbines would pro- duce up to 420 megawatts of renewable wind energy that would, on average, provide 75 percent of theelec- tricity needed by Cape Cod, Nantucket, and Martha’s Vineyard. The farm’s energy would be capable of re- placing 2.685 million barrels of oil per year. After years of rigorous and comprehensive review from federal and state agencies,theprojectwasapproved in 2009. Advantages and Disadvantages The first advantage of wind energy is that the fuel is free. The main costs of generating electricity from wind are those of installation, operation, and mainte- nance. The United States has an abundant supply of wind power that can help promote energy inde- pendence from expensive imported energy and thus reduce national economic and security risks. Since 1973, more than $7 trillion has been spent on foreign oil. The wind industry has also created jobs and helped stabilize electricity costs. Since 1980, the cost of wind energy has dropped more than 80 percent. Wind energy has significant long-term benefits for the environment, human health, and global climate change. Wind is a clean, renewable energy resource that is inexhaustible and easily replenished by nature. Wind power plants do not pollute the air or need waste cleanups like fossil-fuel and nuclear-generation plants, and wind turbines do not emit greenhouse gases or cause acid rain. As of 2009, the wind-energy- generating capacity of the United States was 25,170 Global Resources Wind energy • 1347 megawatts, enough electricity to power almost seven million households. To generate the equivalent of that much energy, 112 million barrels of oil or 31.2 million metric tons of coal (a line of 9-metric-ton trucks more than 22,000 kilometers long) would have to be burned each year. A significant disadvantage is that wind is inconsis- tent and intermittent. It is variable power that does not always blow at times of electrical demands. To be cost-effective, wind sites are located where both strong winds and land are available, usually in remote loca- tions, far from large population centers where con- sumer demand is the greatest. For instance, China’s major wind-energy resourcesarelocatedintheNorth- ern China wind belt, including the sparsely popu- lated Xinjiang Uygur and the windy grasslands of Nei Monggol. Even in locations where winds are strong, there are wide differences in wind velocities over rela- tively short distances. To meet these challenges, storage of surplus wind energy and electrical distribution systems to transmit this energy to consumers are necessary. Wind power can be stored in batteries, and technology already ex- ists that can convert wind energy into fuels suchaseth- anol and hydrogen. However, economic feasibility is a major consideration. Enhanced electrical transmis- sion systems improve reliability for consumers, relieve congestion in existing systems, and provide access to new and remote wind-generation sources. Typically, large wind plants are connected to the local electric utility transmission network. In the European Union, there is a proposal for a super grid of interconnected wind farms in Western Europe, including Denmark, England, Ireland, and France. On a smaller scale, distributed energy is a viable so- lution. Consumers can make their own wind power with private wind turbine and batteries as backup. As more communities or individual consumers use dis- tributed energy, they lower the costs of central wind power plants and transmission systems. Established in 1987, Southwest Windpower in Arizona is the world’s leading producer of small wind turbines. Applications include offshore platform lighting, remote homes and cabins, utility-connected homes and businesses, water pumping, andtelecommunications. Their wind generators often work as part of a hybrid wind-solar battery-charging system. Also, small domestic turbines can complement powerfrom a larger electrical power system, and utility companies buy back any surplus electricity. There are also aesthetic and environmental con - cerns surrounding the large-scale implementation of wind energy. Local residents and public advocacy groups have often opposed wind farms because of the rotor noise, visual impact, and potential harm to property values and local wildlife and its habitats. For instance, in 2001, residents concerned abouttheenvi- ronment opposed the proposal of the Cape Wind Project, the first offshore wind farm in the country. In many cases, technological advances and theappropri- ate sitingof the wind generators away from populated areas have mitigated the problems. The Future of Wind Energy Wind energy is already one of the fastest-growing en- ergy sources, and the market is forecast to expand in the future. Wind power is affordable, readily avail- able, and renewable. Wind energy technology has de- veloped to the point that it can compete successfully with conventional power generation technologies, such as oil, nuclear, coal, and most natural gas-fired generation. As of 2008, the world’s ten largest producers of wind power were the United States, Germany, Spain, China, India, Italy, France,theUnitedKingdom, Den- mark, and Portugal. There is major wind-energy de- velopment globally, and in some countries, wind-power generation has been increasing exponentially. In 2008, in Australia, numerous wind farm projects were ap- proved, and wind power is expected to provide more than 20 percent of the country’s energy by 2020. China has been rapidly increasing its installed wind- power capacity each year since 2005, and estimates predicted that China would achieve a capacity of 100 gigawatts by 2020. Utility companies have increased investments in wind farms and wind technology. In 2005, General Electric’s turbine business doubled, and by 2009, it was the leading U.S. wind turbine supplier and a world leader, with more than ten thousand wind tur- bine installations worldwide, comprising more than 15,000 megawatts of capacity. GE operates wind power manufacturing and assembly facilities in Spain, Can- ada, China, Germany, and the United States. In 2008, GE passed the $4 billion mark in investments in wind farms. Vestas, the Danish company thatis the world’s lead- ing wind supplier, had $5.7 billion in revenues in 2008. In Denmark, wind energy equaled 20 percent of total energy consumption. Vestas had installed more 1348 • Wind energy Global Resources than thirty-eight thousand wind turbines in sixty-two countries on five continents to serve an estimated forty-five million people worldwide. By 2009, Vestas was installing an average of one wind turbine every three hours, twenty-four hours a day. In 2008, the U.S. wind energy industry surpassed previous records for installations and was second only to the natural gas industry in adding new capacity. Enough new wind-power-generating capacity to ser- vice more than two million homes, 8,500 megawatts, was installed. These wind projects increased the na- tion’s entire wind-power-generating capacity to more than 25,300 megawatts and equaled 42 percent of the U.S.’s total power-producing capacity that was added. The new wind-energy capacity had the same effect as taking more than seven million cars off the road or preventing almost 40 million metric tons of carbon emissions. Significantly, there has been increasing federal gov- ernment support of wind power. In 2008, the U.S. Department of Energy released its groundbreaking technical report Twenty Percent Wind Energy by 2030: Increasing Wind Energy’s Contribution to U.S. Electricity Supply. More than one hundred people from govern- ment, industry, utilities, and nongovernment organi- zations worked on this report, which supports a sce- nario in which by 2030, wind power would supply 20 percent of U.S. electricity. Other benefits would be to reduce emissions of greenhouse gases by 25 percent, avoid consumption of 15 trillion liters of water, cut electric sector water consumption by 17 percent, cre- ate $2 billion in local annual revenues through jobs and other economic benefits, and reduce nationwide natural gas use by 11 percent with savings of $86-$214 billion for gas consumers. The Department of Energy has also researched the use of wind energy for hydro- gen production, water treatment and irrigation, and hydropower applications. The American Recovery and Reinvestment Act of 2009 provided measures to benefit renewable energy, including a Treasury Department grant program for renewable energy developers, increased funding for research and development, and a manufacturing tax credit. The ARRA also includes an extension of the wind-energy production tax credit to December 31, 2012. Consumers are allowed federal tax credits for energy efficiency, including tax credits of 30 percent of the cost of residential small wind turbines placed in service before December 31, 2016. Thomas W. Weber, updated by Alice Myers Further Reading Baker, T. Lindsay. American Windmills: An Album of His- toric Photographs. Norman: University of Oklahoma Press, 2007. Bartmann, Dan, and Dan Fink. Homebrew Wind Power: A Hands-on Guide to Harnessing the Wind. Mason- ville, Colo.: Buckville, 2008. Chiras, Dan, MickSagrillo,and Ian Woofenden. Power from the Wind: Achieving Energy Independence.Ga- briola Island, B.C.: New Society, 2009. Craddock, David. Renewable Energy Made Easy: Free En- ergy from Solar, Wind, Hydropower, and Other Alterna- tive Energy Sources. Ocala, Fla.: Atlantic, 2008. Evans, Robert L. Fueling Our Future: An Introduction to Sustainable Energy. NewYork: Cambridge University Press, 2007. Foster, Robert, ed. Wind Energy: Renewable Energy and the Environment. BocaRaton,Fla.:CRCPress,2009. Gillis, Christopher. Wind Power. Atglen, Pa.: Schiffer, 2008. Gipe, Paul. Wind Energy Basics: A Guide to Home- and Community-Scale Wind-Energy Systems. White River Junction, Vt.: Chelsea Green, 2009. _______. Wind Energy Comes of Age. New York: Wiley, 1995. Nelson, Vaughn. Wind Energy: Renewable Energy and the Environment. Boca Raton, Fla.: CRC Press, 2009. Pickens, T. Boone. The First Billion Is the Hardest: Reflec- tions on a Life of Comebacks and America’s Energy Fu- ture. New York: Crown Business, 2008. Righter, Robert W. Wind Energy in America: A History. Norman: University of Oklahoma Press, 1996. Scientific American. Energy for Planet Earth. New York: Author, 1990. Sorensen, Harry A. Energy Conversion Systems. New York: J. Wiley, 1983. Stiebler, Manfred. Wind Energy Systems for Electric Power Generation. Berlin: Springer, 2008. Wizelius, Tore. Developing Wind Power Projects: Theory and Practice. Sterling, Va.: Earthscan, 2007. Web Site U.S. Department of Energy Wind http://www.energy.gov/energysources/wind.htm See also: Athabasca oil sands; Biofuels; Department of Energy, U.S.; Energy storage; Renewable and non - renewable resources; Resources for the Future; Solar energy. Global Resources Wind energy • 1349 Wise use movement Category: Historical events and movements The wise use movement is a term generally used to de- scribe individuals and groups that oppose either the mainstream environmental movement or the federal government’s policies on natural resources and land use. The movement has antecedents in earlier social movements in the United States but became most active during the 1990’s. Definition The term “wise use” was first used by conservationist and forester Gifford Pinchot in his autobiography Breaking New Ground (1947). Pinchot believed in sus- tainable management and the multiple use of natural resources—the base philosophy of the wise use move- ment. Overview The roots of the wise use movement can be traced to the Sagebrush Rebellion, which occurred in the late 1970’s and early 1980’s in the West. Cattleand mining interests joined together to try to force the federal government to return public domain lands to the states, but they were unsuccessful in convincing mem- bers of Congress to do so. In the late 1970’s, the timber industry became one of the wise use movement’s supporters by leading op- position to a proposed ban on logging near Califor- nia’s Redwood National Park. Atabout the same time, private property owners in Yosemite National Park, called inholders, began to organize against the fed- eral government’s policies on land use. Other groups opposed the implementation of the Endangered Spe- cies Act (1973) and the restrictions it placed on using land considered wildlife habitat. Added to the mix were motorized recreational vehicle userswho sought to have wilderness areas opened up for their use. These varied interests came together under a vari- ety of umbrella organizations that serve primarily as clearinghouses for information. Two men, Ron Ar- nold and Alan Gottlieb, formed the Center for the De- fense of Free Enterprise, which published The Wise Use Agenda in 1989, outlining the movement’s core phi- losophy. Other umbrella groups, such as the Alliance for America and the Blue Ribbon Coalition, work to - ward reform of natural resource regulations, target - ing the Endangered Species Act and wetlands desig - nations under the Clean Water Act, and seek to open up more wilderness areas for public use by snowmo- biles and off-highway vehicles. It is impossible to estimate how many individuals are involved in or support the wise use movement, since there is no “membership” in the traditional sense. Most individuals are counted as members be- cause they belong to an organization, such as the American Farm Bureau Federation, which supports one of the umbrella groups. Despite claims by membersofsome environmental organizations that the wise use movement is a front for industryinterests,themajorityofthegroups,espe- cially those seeking changes in property rights poli- cies, appear to be genuinely grassroots-based. Unlike organized business and trade lobbies, most wise use groups do not have the financial resources to engage in strategies such as making contributions to candi- dates or maintaining a full-time lobbying presence in Washington, D.C. Instead, they hold rallies, urge their members to write their representatives in Congress, and try to develop public support against regulations and policies which they oppose. Jacqueline Vaughn Switzer See also: Conservation; Land-use regulation and control; Multiple-use approach; Pinchot, Gifford; Public lands; Sagebrush Rebellion; Takings law and eminent domain; Taylor Grazing Act. Wollastonite Category: Mineral and other nonliving resources Where Found Wollastonite is a common mineral; large deposits worldwide have been formed by contact metamor- phism where granite intrudes into limestone rocks. Deposits formed in this way exist in the United States (California and New York), Mexico, Canada (Quebec and Ontario), China, andIndia.Wollastonite is found in volcanic ash and is formed by some volcanoes as molten lava interacts with limestone strata. Primary Uses Wollastonite is widely used in industry as functional filler. Most commercially mined wollastonite is used 1350 • Wise use movement Global Resources in the production of plastic polymers and ceramics. It is used in production of nylon 6 and polypropylene. Wollastonite is used in paints, construction products, metallurgical processes, and the production of med- ical bone cements and dental implants. Ground wol- lastonite is used in remedial treatment of soils con- taminated by acid deposition. Wollastonite has also been used in friction products, including brake-drum linings. Technical Definition Wollastonite is a mineral composed of calcium, oxy- gen, and silicon, with a chemicalcompositionCaSiO 3 , sometimes called calcium inosilicate or calcium sili- cate. Wollastonite has triclinic symmetry, forming long, needlelike crystals with splintery or unevenfrac- tures. It has a Mohs hardness of 5, similar to the min- eral apatite and harder than fluorite. It is soluble in concentrated hydrochloric acid. Some wollastonite specimens fluoresce yellow or orange under short- wave ultraviolet light. It has a very low loss on ignition (LOI). Pure wollastonite may be transparent and col- orless or translucent and white; impurities cause a pink, brown, or green coloration.Itsstreakcoloration is white. Description, Distribution, and Forms Wollastonite isacontact metamorphic mineral formed when granitic magma intrudes into limestone or do- lomite strata, creating what geologists call a “skarn” deposit. Skarn deposits of wollastonite usually con- tain garnets and other minerals which are removed and discarded during ore process- ing. Wollastonite is a common mineral, with exploitable deposits known from many lo- cales around the world. At the close of the twentieth century, most of the world’s sup- ply was mined in China, the United States, and India, with anunknown amount mined and used in Russia. Mining operations by NYCO in Mexico were expected to supply large amounts of wollastonite to the world market in the early twenty-first century. The mineral wollastonite is composed of long, single chains of silicates, sometimes referred to as “pyroxenoid” structures. Tet- rahedral groups of silica are linked together by calcium cations to form a long, crystal chain. Occasionally atoms of iron, manga - nese, or magnesium replace calcium in the crystal matrix. These impurities cause pastel color - ations of yellow, pink, and green. Excellent wollastonite crystals are on display in most large science museums worldwide. Many speci- mens displayed in museums have grown in vugs (cavi- ties inside rocks), allowing clear, perfect, large crys- tals of wollastonite to form. Certain volcanic localities, including Monte Somma/Vesuvius, are renowned for wollastonite-filled vugs. Wollastonitechunksareoften used in museum displays of fluorescent minerals, where under ultraviolet light (“black light”) an other- wise unimpressive rock produces a bright orange col- oration. Wollastonite specimens from Franklin, New Jersey, are especially well known from U.S. museum displays and sought by private collectors because of their orange fluorescence. The aspect (length-to-width) ratio of wollaston- ite crystals determines the mineral’s application and hence value. Powders, with low aspect ratios of 3:1, are used in metallurgy and in paints and coatings. Wollastonite withhighaspectratios (ranging between 10:1 and 20:1) is more expensive than low-aspect wollastonite. History Prior to 1822, the mineral wollastonite was known in England as table spar or tabular spar. It was renamed at that time for William Hyde Wollaston, who had in- vestigated its physical and chemical properties in the late eighteenth century. Mineral specimens of wollastoniteforscientific dis- Global Resources Wollastonite • 1351 Wollastonite is generally used in ceramics and plastic polymers. (USGS) play and comparison were collected in the nineteenth century, when geologists used both “wollastonite” and “table spar” to refer to field specimens. Bustamite (CaMnSi 2 O 6 )—a pink or red-colored inosilicate mineral similar to wollastonite, but with manganese alternating with calcium in the mineral lattice—was referred to as “manganese wollastonite” by mineralo- gists during the nineteenth and early twentieth centu- ries. Bustamite may be found with wollastonite in metamorphic rocks. In the United States, wollastonite was commer- cially mined beginning in 1933,inCalifornia, to use as mineral wool. Following theKorean War,the building boom required increasing amounts of wollastonite- containing construction products. In 2006, about 450,000 metric tons of refined wol- lastonite were sold worldwide, with China the world’s largest producer, followed by the United States and India. Demand for wollastonite grew during the last several decades of the twentieth century, because it became a substitute for asbestos (which posed health risks and hence was not mined in the United States after 2002) and because of its versatility as inexpensive functional filler in paints, coatings, polymers, and ceramics. In the early twenty-first century, interest in using wollastonite in bone cements and other bio- medical applications grew. Obtaining Wollastonite The extensive wollastonite deposits commercially ex- ploited were all formed when granite intruded into limestone or dolomite, causing large-scale contact metamorphism. Wollastonite is commonly strip- mined, with some large open-pit operations and a few underground mines using drill-and-blast methods. Small amounts of synthetic wollastonite are pro- duced by sintering ground silica and calcite in rotary kilns. The wollastonite crystals produced are short (have low aspect ratios) and powdery. Synthetic wol- lastonite costs more to produce than the natural min- eral, and its use is usually restricted to metallurgical and ceramic processes that require very pure and extremely uniform crystals. Uses of Wollastonite Wollastonite is a versatile nonmetallic mineral with many different industrial uses. Its industrial applica- tions expanded dramatically following the discovery of the carcinogenicity of the mineral asbestos, which had been banned in most countries by the mid-1980’s. The U.S. OccupationalSafety and Health Administra - tion (OSHA) recognizes wollastonite dust particles as an irritant, associated with reduced pulmonary func- tion when inhaled, but not as a carcinogen. Addition of wollastonite to products increases their strength and alkalinity, enhancing corrosion resistance. The ceramics industry accounts for about 25 to 30 percent of the wollastonite used within the United States. The needlelike crystalline structure, LOI, and white coloration are important attributes that wol- lastonite contributes to ceramics. It is widely used as filler in ceramics, and in ceramic glazes, frits, and enamels, where it is well known for minimizing shrink- age and crazing. Wollastonite is used in the produc- tion of ceramic electrical insulators. Wollastonite is widely used in plastic polymers and elastomers, where it adds structural strength. Within the United States, about 35 to 40 percent of wol- lastonite is consumed by the plastics industry. It is used in automotive plastics. In metallurgical applications, wollastonite is used in molds for casting aluminum and continuous cast- ing of steel, where it absorbs impurities. Wollastonite is also usedasaweldingfluxandasaslagconditioner. In the construction industry, high-aspect-ratio wol- lastonite is used in to enhance strength and durability. It is used as filler in portland cement and in the pro- duction ofwallboard. It is used inroofing materials. It is also used as backing for linoleum. Addition of wollastonite to latex paint increases mildew resistance. Wollastonite used in paint and coatings is sometimes treated with silane. Wollastonite-containing medical products are able to act as a substrate for natural bone growth. Wol- lastonite-containing ceramics, including Bioglass and Cerabone ® AW, can bond with living bone and are in- creasingly used in implants. Applications of wollastonite have been explored for tertiary wastewater treatment and for treating acidified soils. A high-pH slurry of water and ground wollastonite applied to environments contaminated by high levels of acid deposition increases foliage growth and promotes plant germination. Anita Baker-Blocker Further Reading Dunn, Peter J. Franklin and Sterling Hill, New Jersey: The World’s Most Magnificent Mineral Deposits. Peekskill, N.Y.: Excalibur Mineral Company, 2004. Jeffrey, Kip. “Industrial Minerals Development in 1352 • Wollastonite Global Resources Saudi Arabia.” In Industrial Minerals and Extractive Industry Geology: Based on Papers Presented at the Com- bined Thirty-sixth Forum on the Geology of Industrial Minerals and Eleventh Extractive Industry Geology Con- ference, edited by P. W. Scott andC. M. Bristow. Lon- don: Geological Society, 2002. Klein, Cornelius, andBarbara Dutrow. Manualof Min- eral Science. 23d ed. New York: Wiley, 2007. Nicholson, John W. The Chemistry of Medical and Dental Materials. London: Royal Society of Chemistry, 2002. Philpotts, Anthony, and Jay Ague. Principles of Igneous and Metamorphic Petrology. 2d ed. New York: Cam- bridge University Press, 2009. Web Sites Natural Resources Canada Canadian Minerals Yearbook, 2005: Wollastonite http://www.nrcan.gc.ca/smm-mms/busi-indu/cmy- amc/content/2005/66.pdf U.S. Geological Survey Mineral Information: Wollastonite Statistics and Information http://minerals.usgs.gov/minerals/pubs/ commodity/wollastonite/ See also: Agriculture industry; Asbestos; Oxygen; Sil- icon. Wood and charcoal as fuel resources Categories: Energy resources; plant and animal resources Globally, the amount of wood utilized for fuel exceeds the total amount of wood utilized for all other purposes. Between 15 and 80 percent of the total energy needs of some developing countries are met by wood. Background Wood and charcoal are some of the oldest energy sources: They have provided fuel for human energy needs since prehistoric times. Rough wood and bark may be burned directly for fuel, or wood may be con- verted into charcoal by charring in a kiln from which air has been excluded. Accordingto the Food and Ag - riculture Organization of the United Nations, more than half of all the wood utilized in the world is used for energy production. Wood provides up to 80 per- cent of the total energy needs of some developing countries, but it provides less than 5 percent of the to- tal energy requirement in most developed countries. In some developing areas of the world, fuelwood de- mand is greater than the supply; particularly in parts of Africa, consumption significantly exceeds replace- ment of the stock of trees. Wood fuel also finds some use in industry, as in the paper industry. Industrial uses often burn waste material from other manufacturing processes. Bark removed from raw logs, sawdust, planer shavings, sander dust, edges, and trim pieces may all be burned to generate power while disposing of the unwanted material. Small wood particles such as sawdust and shavings may be compressed to produce briquets or “logs” for use as fuel. Increasing numbers of forests have been planted and cultivated for the sole purpose of energy produc- tion. Entire trees are chipped and burned for energy production at the end ofa rotation. These forests may be known as forest plantations, tree farms, or energy forests. This type of woodproduction and fuel use has the potential to reduce dependency on fossil fuels. Energy forests remove carbon from the atmosphere over their life spans, then release this carbon in vari- ous forms during combustion for energy production. Types of Combustion The direct burning of wood occurs when the surface is intensively irradiated so that the temperature is raised to the point of spontaneous ignition, anywhere from 260° to more than 480° Celsius, depending on the conditions. More common is indirect combus- tion, in which the wood breaks down into gases, va- pors, and mists, which mix with air and burn. About 1.3 kilograms of oxygen are required for the complete combustion of 1 kilogram of wood. At normal atmo- spheric concentrations, this implies that about 5 kilo- grams of air are needed for the complete combustion of 1 kilogram of wood. During combustion, gases such as carbon dioxide andcarbonmonoxide, water vapor, tars, and charcoal are produced, along with a variety of other hydrocarbons. Dry wood or bark and char- coal burn relatively cleanly; wetter wood produces a larger amount of emissions. Collectors may be used to remove particulate matter from industrial sources. It is less feasible to reduce emissions from cooking stoves (either chemically or mechanically), however, Global Resources Wood and charcoal as fuel resources • 1353 and cooking stoves are a major source of human ex - posure to emissions from wood burning in much of the world. Charcoal Charcoal is lighter thanwood and has a higherenergy content. It takes approximately 2.5kilograms of wood to produce 1 kilogram of charcoal. The exact conver- sion ratio depends on the tree species, the form of wood utilized, and the kiln technologyused.Charcoal is more efficient to transport than wood, and it can be burned at higher temperatures. It is used both for domestic purposes and, insome countries—Brazil for example—as an industrial fuel. In general, charcoal is considered a cleaner, less polluting fuel than wood in that its combustion produces fewer particulates. Charcoal was used extensively as an energy source for smelting and metalworking from prehistoric times into the Industrial Revolution, but coal eventually be- came the principal alternative energy source for these processes in areas where it was available. Today, petro - leum and natural gas are major sources of energy for industrial processes. Energy Content The average recoverable heat energy from 0.5 kilo- gram of wood is about 8,500 British thermal units (Btus). The value ranges from 8,000 to 10,000 Btus per 0.5 kilogram for different species. In some effi- cient processes, 12,500 Btus can be recovered from 0.5 kilogram of charcoal. If wood withahigh moisture content is burned, some of the energy produced by combustion is absorbed as the moisture evaporates, reducing the recoverable energy. Impacts on Environment and Health Traditional uses of wood fuel for cooking and home heating utilize woody material obtained from tree pruning or agroforestry systems. These uses are sus- tainable and have relatively little environmental im- 1354 • Wood and charcoal as fuel resources Global Resources A Filipino family cooks dinner using wood fuel, a common practice, especially in developing countries where other forms of fuel prove too ex - pensive. (AFP/Getty Images) pact in areas with low human population levels, but they may be associatedwithseriousair pollution prob- lems as well as widespread deforestation and erosion if they are the major sources of energy for a large or concentrated population. In most of the areas that have deforestation problems, the problem is primar- ily attributable to changes in landuse, particularly the opening of land for agriculture and grazing. Fuelwood is often recovered during such land-use changes, but the need for fuelwood production is often a second- ary cause or by-product of deforestation. Industrial power production that utilizes available technology to ensure high-temperature, virtually com- plete combustion minimizes hydrocarbon and partic- ulate emissions and can be designed to meet most ex- isting air quality standards. Less efficient domestic combustion may be associated with unacceptable levels of human exposure to airborne particulates, carbon monoxide, and other hydrocarbons produced by in- complete combustion. The health effects of exposure to domestic wood fires are difficult to determine, since it often occurs along with other factors known to in- crease health risks. However, as noted by the nonprofit organization Environment and Human Health and other organizations, wood smoke contains particu- lates as well as recognized carcinogenic compounds that, depending on the circumstance of exposure, can pose risks similar to those of cigarette smoke. David D. Reed Further Reading Argyropoulos, Dimitris S., ed. Materials, Chemicals,and Energy from Forest Biomass. Washington,D.C.:Ameri- can Chemical Society, 2007. Buxton, Richard H. How to Convert Wood into Charcoal and Electricity. Bradley, Ill.: Lindsay, 2003. Food and Agriculture Organization of the United Na- tions. FAO Yearbook: Forest Products. Rome: Author, 2008. _______. Forests and Energy: Key Issues. Rome: Author, 2008. _______. State of the World’s Forests, 2009. Rome: Au- thor, 2009. Leach, Gerald, and Robin Mearns. Beyond the Woodfuel Crisis: People, Land, and Trees in Africa. London: Earthscan, 1988. Pasztor, Janos, and Lars Kristoferson. “Biomass En- ergy.” In The Energy-Environment Connection, edited by Jack M. Hollander. Washington, D.C.: Island Press, 1992. Röser, Dominik, et al., eds. Sustainable Use of Forest Bio - mass for Energy: A Synthesis with Focus on the Baltic and Nordic Region. Dordrecht, the Netherlands: Springer, 2008. Solomon, BarryD.,andValerie A. Luzadis, eds. Renew- able Energy from Forest Resources in the United States. New York: Routledge, 2009. State of the World’s Forests, 2009. Rome: Food and Agri- cultureOrganization oftheUnitedNations,2009. Web Sites Forest Products Laboratory, U.S. Forest Service Wood Biomass for Energy http://www.fpl.fs.fed.us/documnts/techline/wood- biomass-for-energy.pdf United Nations, Food and Agriculture Organization Definition: Wood Energy http://www.fao.org/forestry/14011/en See also: Deforestation; Developing countries; En- ergy economics; Erosion and erosion control; Refor- estation; Renewable and nonrenewable resources; Sustainable development; Wood and timber. Wood and timber Category: Plant and animal resources No other material has all the advantages of wood. One material may equal wood in insulating quality but lack its abundance and low cost. Another may rival it in strength but fail on the point of workability. A third may rank with it in workability but fail to measure up in durability. If wood were a newly discovered mate- rial, its properties would startle the world. Background Since the human race first started to build crude shel- ters at the dawn of civilization, wood has been avail- able as a construction material. Wood has long been used in the construction of buildings, bridges, and boats. As technologydeveloped,wood also found ava- riety of less readily recognizable forms, such as paper, films, and pulp products, many of which are mainstays of daily life. Global Resources Wood and timber • 1355 . number of kilowatts by the number of hours equals the kilowatt-hours. One kilowatt-hour equals the energy of one kilowatt produced or used for a period of one hour. 1346 • Wind energy Global Resources The. Site U.S. Department of Energy Wind http://www.energy.gov/energysources/wind.htm See also: Athabasca oil sands; Biofuels; Department of Energy, U.S.; Energy storage; Renewable and non - renewable resources; . Sil- icon. Wood and charcoal as fuel resources Categories: Energy resources; plant and animal resources Globally, the amount of wood utilized for fuel exceeds the total amount of wood utilized for all other