ENERGY SUPPLY, WORLD
BACKGROUND OF TODAY’S SITUATION
PETROLEUM
COAL
SYNTHETIC FUELS
NUCLEAR ENERGY
SOLAR ENERGY
GEOTHERMAL ENERGY
ENERGY EFFICIENCY IMPROVEMENTS
ENERGY SUPPLY, WORLD, combined resources by which the nations of the world attempt to meet their energy needs. Energy is the basis of industrial civilization; without it, modern life would cease to exist. During the 1970s the world began a painful adjustment to the vulnerability of energy supplies. In the long run, conservation practices may provide the time to sort out the range of potential technological options. While that process occurs, however, the world will continue to be vulnerable to disruptions in the supply of oil, which, after World War II, became the most favored energy source.
WORLD PRIMARY ENERGY CONSUMPTION BY SOURCE OF ENERGY, 1990
Quadrillion (1015) Btu Percent
Petroleum 135.01 39.2
Dry natural gas 73.69 21.4
Coal 93.20 27.1
Net hydroelectric power 21.96 6.4
Net nuclear power 20.35 5.9
Total 344.21 100.0
Source: U.S. Department of Energy
BACKGROUND OF TODAY’S SITUATION
Growth of Petroleum Use
Formation of OPEC
The Energy Crisis
Current Status
Wood was the first and, for most of human history, the major source of energy. It was readily available because extensive forests grew in many parts of the world, and the amount of wood needed for heating and cooking was relatively modest. Certain other energy sources, found only in localized areas, were also used in ancient times: asphalt, coal, and peat from surface deposits and oil in seepages from underground deposits.
This situation changed when wood began to be used during the Middle Ages to make charcoal, which in turn was used to reduce ores to metals. As forests were cut and wood supplies dwindled at the onset of the Industrial Revolution, charcoal was replaced by coke from coal in the reduction of ores. Coal, which also began to be used to drive steam engines, became the dominant energy source as the Industrial Revolution proceeded.
Growth of Petroleum Use
Although petroleum had been used in small quantities for centuries for purposes as diverse as medicine and building, the modern petroleum era began when a commercial well was brought into production in Pennsylvania in 1859. The American oil industry expanded rapidly as refineries sprang up to make oil products from crude oil. The oil companies soon began exporting their principal product, kerosene—used for lighting—to all areas of the world. The development of the internal-combustion engine and the automobile created a vast new market for another major product, gasoline; and a third major product, heating oil, began to replace coal in many energy markets.
The oil companies, which are based principally in the U.S., initially found much larger oil supplies in the U.S. than in other countries. As a result, oil companies from other countries—especially Great Britain, the Netherlands, and France—began to search for oil in many parts of the world, especially the Middle East. The British brought the first field there (in Iran) into production just before World War I. During World War I, the U.S. oil industry produced two-thirds of the world’s oil supply from domestic sources and imported another one-sixth from Mexico. At the end of the war and before the discovery of the productive East Texas fields, however, the U.S., with its reserves strained by the war, became a net oil importer for a few years.
During the next three decades, with occasional federal support, the U.S. oil companies were enormously successful in expanding in the rest of the world. By 1955 the five major U.S. oil companies produced two-thirds of the oil for the world oil market (not including North America and the Soviet bloc). Two British-based companies produced almost one-third, and the French a mere one-fiftieth. The next 15 years were a period of serenity for energy supplies. The seven major U.S. and British oil companies provided the world with increasing quantities of cheap oil from the vast pools in the Middle East. The world price was about a dollar a barrel, and during this time the U.S. was largely self-sufficient, with its imports limited by a quota.
Formation of OPEC
Two series of events coincided to change this secure supply of cheap oil into an insecure supply of expensive oil. In 1960, enraged by unilateral cuts in oil prices by the seven big oil companies, the governments of the major oil-exporting countries—Venezuela and four countries around the Persian Gulf—formed the Organization of Petroleum Exporting Countries, or OPEC, to try to prevent further cuts in the price they received for oil. They succeeded, but for a decade they were unable to raise prices. In the meantime, increasing oil consumption throughout the world, especially in Europe and Japan, where oil displaced coal as a primary source of energy, caused an enormous expansion in the demand for oil products.
The Energy Crisis
The year 1973 brought an end to the era of secure, cheap oil. In October, as a result of the Arab-Israeli war, the Arab oil-producing countries cut back oil production and embargoed oil shipments to the U.S. and the Netherlands. Although the Arab cutbacks represented a loss of less than 7 percent in world supply, they created panic on the part of oil companies, consumers, oil traders, and some governments. Wild bidding for crude oil ensued when a few producing nations began to auction off some of their oil. This bidding encouraged the OPEC nations, which now numbered 13, to raise the price of all their crude oil to a level as high as eight times that of a few years earlier. The world oil scene gradually calmed, as a world-wide recession brought on by the higher oil prices trimmed the demand for oil. In the meantime, most OPEC governments took over ownership of the oil fields in their countries.
In 1978 a second oil crisis began when, as the result of the revolution that eventually drove the shah of Iran from his throne, Iranian oil production and exports dropped to negligible levels. Because Iran had been a major exporter, consumers again panicked. A replay of 1973 events, complete with wild bidding, again forced up oil prices during 1979. The outbreak of war between Iran and Iraq in 1980 gave a further boost to oil prices. By the end of 1980 the price of crude oil stood at 19 times what it had been just ten years earlier.
The very high oil prices again caused a worldwide recession and gave energy conservation a big push; as oil demand slackened and supplies increased, the world oil market slumped. Significant increases in non-OPEC oil supplies, such as in the North Sea, Mexico, Brazil, Egypt, China, and India, pushed oil prices even lower. USSR production reached 11.42 million barrels per day by 1989, which accounted for 19.2 percent of world production in that year.
Despite the low world oil prices that have prevailed since 1986, concern over disruption has continued to be a major focus of energy policy in the industrialized countries. The short-term increases in prices following Iraq’s invasion of Kuwait reinforced this concern. Owing to its vast reserves, the Middle East will continue to be the major source of oil for the foreseeable future.
Current Status
The industrialized nations use most of the world’s energy. Energy usage in America, Europe, the former USSR, and Japan in 1990 was about three-fourths of the world total. Energy usage per person varied widely: for example, from five times the world average in the U.S. to only one-seventh the world average in India. Liquid and gaseous fuels provided more than three-fifths of the world’s commercial energy consumption in 1990. Coal also was an important source, but nuclear energy, solar energy, geothermal energy, wood, waterpower, and other alternatives were relatively minor sources.
WORLD PRIMARY ENERGY CONSUMPTION BY GEOGRAPHICAL REGION, 1990
Quadrillion(1015) Btu* Percent
U.S. 81.17 23.6
Canada 10.79 3.1
Rest of the Americas 19.24 5.6
Germany (West and East) 15.73 4.6
USSR (including all republics) 57.15 16.6
Rest of Europe 63.16 18.3
Middle East and Africa 20.62 6.0
Japan 18.18 5.3
China 28.85 8.4
Rest of Asia and Oceania 29.32 8.5
Total 344.21 100.3†
*These figures include petroleum, dry natural gas, coal, net hydroelectric power, and net nuclear power.
†Percent does not add up to 100 because of rounding figures to nearest tenth.
Source: U.S. Department of Energy
PETROLEUM
Oil well
Drilling
Production
Reserves
Pollution Problems
Oil well
Petroleum usually refers just to crude oil, but the term can also apply to natural gas and shale oil. Crude oil and natural gas are found in commercial quantities in sedimentary basins in more than 50 countries in all parts of the world. The largest deposits are in the Middle East, which contains more than half the known oil reserves and almost one-third of the known natural-gas reserves. In contrast, the U.S. contains only about 6 percent of the world’s known sources.
Drilling
Drilling: Oil
Drilling: Oil
Geologists and other scientists have developed techniques that indicate the possibility of oil or gas being found deep in the ground. These techniques include aerial photography of special surface features, shock waves sent through the earth and reflected back into instruments, and meters to measure the earth’s gravity and magnetic field. Nevertheless, the only method by which oil or gas can be found is by drilling a hole into the reservoir. In some cases oil companies spend many millions of dollars drilling in promising areas, only to find dry holes. For a long time, most wells were drilled on land, but after World War II, drilling commenced in shallow water from platforms supported by legs that rested on the sea bottom. Later, floating platforms were developed that could drill at water depths of 1000 m (3300 ft) or more. Large oil and gas fields have been found offshore: in the U.S., mainly off the Gulf Coast; in Europe, primarily in the North Sea; in Russia in the Barents Sea and Kara Sea; and off Brazil. Most major finds in the future may be offshore.
Production
As gas and oil are produced from a petroleum field, the pressure in the reservoir that forces the material to the surface gradually declines. Eventually, the pressure will decline so much that the remaining oil or gas will not migrate through the porous rock to the well. When this point is reached, most of the gas in a gas field will have been produced, but less than one-third of the oil in an oil field will have been extracted. Part of the remaining oil can be recovered by using gas or water to push the oil to the well, but even then, one-fourth to one-half the oil is usually left in the reservoir. In an effort to extract this remaining oil, oil companies are now beginning to use chemicals to push the oil to the well, or to use fire or steam in the reservoir to make the oil flow easier. New techniques that allow operators to drill horizontally, as well as vertically, into very deep structures have dramatically reduced the cost of finding natural gas and oil supplies.
Crude oil is transported to refineries by pipelines, barges, or giant oceangoing tankers. Refineries contain a series of processing units that separate the different constituents of the crude oil by heating them to different temperatures, chemically modifying them, and then blending them to make final products, principally gasoline, kerosene, diesel oil, jet fuel, home heating oil, heavy fuel oil, lubricants, and "feedstocks" fed to petrochemical plants.
Natural gas is transported, usually by pipelines, to customers who burn it for fuel or, in some cases, make petrochemicals from it. Natural gas can be liquefied at very low temperatures and transported in special ships. This method is much more costly than transporting oil by tanker. Oil and natural gas compete in a number of markets, especially in generating heat for homes, offices, factories, and industrial processes.
Reserves
Shale oil and tar sands are the most prevalent form of petroleum found in the world. Reserves of these two sources are more than 500 times as great as the world’s combined proved reserves of crude oil. Because of the high cost of converting shale oil and tar sands into usable petroleum products, however, relatively little of the material is produced commercially. An industry to make oil products from tar sands has been started in Canada, and Venezuela is looking at the prospects of developing the vast reserves of heavy oil in its Orinoco River basin. Nevertheless, by the year 2000, the quantity of oil products produced from these two raw materials will be small compared with the total production of conventional crude oil.
Pollution Problems
Pollution: Oil spill
Pollution: Oil spill
In its early days, the oil industry generated considerable environmental pollution. Through the years, however, under the dual influences of improved technology and more stringent regulations, it has become much cleaner. The effluents from refineries have decreased greatly and, although well blowouts still occur, new technology has tended to make them relatively rare. The policing of the oceans, on the other hand, is much more difficult. Oceangoing ships are still a major source of oil spills. In 1990 the U.S. Congress passed legislation requiring tankers to be double hulled by the end of the decade.
Another source of pollution connected with the oil industry is the sulfur in crude oil. Regulations of national and local governments restrict the amount of sulfur dioxide that can be discharged by factories and utilities burning fuel oil. Because removing sulfur is expensive, however, regulations still allow some sulfur dioxide to be discharged into the air.
Natural gas is much cleaner than oil. Because it is a gas at room temperature, it does not pollute rivers and oceans. Also, because it usually contains little sulfur, it burns cleanly.
COAL
Reserves
Current Trends
Pollution Problems
Coal is a general term for a wide variety of solid materials that are high in carbon content. Most coal is burned by electric utility companies to produce steam to turn their generators. Some coal also is used in factories to provide heat for buildings and industrial processes; and a special, high-quality coal is turned into metallurgical coke for use in making steel.
Reserves
The world’s coal reserves are vast. The amount of coal (as measured by energy content) that is technically and economically recoverable under present conditions is five times as large as the reserves of crude oil; and because many high-cost coal reserves exist, the amount that will become recoverable as energy prices rise could well be more than 20 times the quantity of crude oil. Just four regions contain three-fourths of the world’s coal reserves that are now technically and economically recoverable: the U.S., 28 percent; the countries of the former USSR, 17 percent; China, 16 percent; and Western Europe, 14 percent.
Current Trends
The greater convenience and lower costs of oil and gas in the earlier 20th century virtually forced coal out of the market for heating homes and offices and driving locomotives, and ate heavily into the industrial market. Only an expanding utility market enabled coal output in the U.S., for example, to remain relatively constant between 1948 and 1973. Even in the utility market, as oil and gas captured a greater share, coal’s contribution to the total energy picture dropped dramatically—as, in the U.S., from about one-half to less than one-fifth. The dramatic jumps in oil prices after 1973, however, gave coal a major cost advantage for utilities and large industrial customers, and coal began to recapture some of its lost markets.
Pollution Problems
Pollution: Germany
Pollution: Germany
Despite coal’s relative cheapness and huge reserves, the growth in the use of coal since 1973 has been much less than expected, because coal is associated with many more environmental problems than is oil. Underground mining can result in black lung disease for miners, subsidence of the land over mines, and drainage of acid into water tables. Surface mining requires careful reclamation, or the unrestored land will remain scarred and unproductive. In addition, the burning of coal causes emission of sulfur dioxide particles, nitrogen oxide, and other impurities. Acid rain—rainfall and other forms of precipitation with a relatively high acidity that is damaging lakes and some forests in many regions—is believed to be caused in part by such emissions (see AIR POLLUTION). In the 1990s, concern over the possible warming of the planet as a result of the greenhouse effect, caused some governments to consider policies to reduce the carbon dioxide emissions that are produced by burning coal, oil, and natural gas. Solving these problems is costly, and who should pay is a matter of controversy. As a result, coal consumption may continue to grow more slowly than would otherwise be expected. The vast coal reserves, improved technologies to reduce pollution, and the further development of coal gasification (see GASES, FUEL) still indicate, however, an increasing market for coal in coming years.
SYNTHETIC FUELS
Synthetic fuels are made from substances that are found in nature. The fuels most commonly expected to become available in commercial quantities in the 1990s are gasohol, which is a mixture of gasoline and alcohol made from living plants, and fuel gases and liquids made from coal. However, the production of fuel from coal will likely be limited by high costs and pollution problems, some of which are not yet known. The manufacture of alcohol fuels in large quantities will likely be restricted to regions, such as parts of Brazil, where a combination of low-cost labor and land, plus a long growing season, make it economical. Thus, synthetic fuels are unlikely to make an important contribution to the world’s energy supply during the rest of the century.
NUCLEAR ENERGY
Development
Safety Problems
Current Status
Nuclear energy is generated by the splitting of uranium atoms. The heat from this fission process is used to drive a turbine to generate electricity. The operation of a nuclear reactor and the related electric generating equipment is only one part of an interconnected set of activities. The production of a reliable supply of electricity from nuclear fission requires mining, milling, and transporting uranium; "enriching" uranium and packing it in appropriate form; building and maintaining the reactor and associated generating equipment; and treating and disposal of spent fuel. These activities require extremely sophisticated and interactive industrial processes and many specialized skills.
Development
Great Britain took an early lead in developing nuclear power. By the mid-1950s, several nuclear reactors were producing electricity in that country. The first nuclear reactor to be connected to an electricity distribution network in the U.S. began operation in 1957 at Shipping port, Pa. Six years later, the first order was placed for a commercial installation to be built without a direct subsidy from the federal government. This order marked the beginning of an attempt to rapidly convert the world’s electric generating systems from fossil fuels to nuclear energy. The attempts faltered because of rapidly increasing costs, regulatory delays, declining demand for electricity, and a heightened concern for safety.
Safety Problems
Questions about the safety and economy of nuclear power have created perhaps the most emotional battle yet fought over energy. The nuclear advocates—comprising government and business leaders and their allies from the scientific and engineering communities—believe that no realistic alternative exists to increased reliance on nuclear power. They recognize that some problems remain but maintain that solutions will be found. The most effective nuclear opponents, on the other hand, emphasize a number of unanswered questions about the environment: What are the effects of low-level radiation over long periods? What is the likelihood of a major accident at a nuclear power plant? What would be the consequences of such an accident? How can nuclear power’s waste products, which will be dangerous for centuries, be permanently isolated from the environment? These safety questions helped cause changes in specifications for and delays in the construction of nuclear power plants, further driving up costs and helping to create a second controversy: Is electricity from nuclear power plants less costly, equally costly, or more costly than electricity from coal-fired plants? Despite rapidly escalating oil and gas prices and escalating environmental problems with coal, these political and economic problems caused an effective moratorium on new orders for nuclear power plants, even before the 1979 near meltdown at the Three Mile Island nuclear power plant near Harrisburg, Pa., and the 1986 partial meltdown at the Chernobyl plant north of Kiev in Ukraine. The latter accident caused some fatalities and cases of radiation sickness, and it released a cloud of radioactivity that traveled widely across the northern hemisphere.
Current Status
By the late 1980s, the nuclear industry was bogged down in political and economic controversy in most countries. Few orders for new plants were being placed, and, although most plants under construction were being completed, delays abounded and many orders for new plants were canceled. France, with its strong tradition of central control of technical issues, has been a major exception to this pattern, as was the Soviet Union.
As might be expected, estimates of future energy that will be obtained from nuclear power vary widely. Everyone agrees, however, that at least during the 20th century, it will not be the panacea its advocates once foresaw. Nuclear power could be producing as much as 10 to 15 percent of the world’s energy by the year 2000, or as little as 1 or 2 percent. Two advanced means of nuclear power generation—the breeder reactor and nuclear fusion technology—can make essentially no contribution to energy supply until well into the next century.
SOLAR ENERGY
Heating and Cooling
Generation of Electricity
Biomass
Current Status
Solar energy is not a single energy technology but a term that covers a diverse set of renewable energy technologies. Their common feature is that, unlike oil, gas, coal, and present forms of nuclear power, solar energy is inexhaustible. Solar energy can be divided into three main groups—heating and cooling applications, electricity generation, and fuels from biomass.
Heating and Cooling
The sun has been used for heating for centuries. The Mesa Verde cliff dwellings in Colorado were constructed with rock projections that provide shade from the high (and hot) summer sun but allow the rays of the lower winter sun to penetrate. Today a design with few or no moving parts that takes advantage of the sun is called passive solar heating. Beginning in the late 1970s, architects increasingly became familiar with passive solar techniques and, in the future, more and more new buildings will be designed to capture the sun’s winter rays and keep out the summer rays.
Active solar heating and solar hot-water heating are variations on one theme, differing principally in cost and scale. A typical active solar-heating unit consists of tubes installed in panels that are mounted on a roof. Water (or sometimes another fluid) flowing through the tubes is heated by the sun and is then used as a source of hot water and heat for the building. Although the number of active solar-heating installations has grown rapidly since the 1970s, the industry has encountered simple installation and maintenance problems, involving such commonplace occurrences as water leakage and air blockage. Solar cooling requires a higher technology installation in which a fluid is cooled by being heated to an intermediate temperature so that it can be used to drive a refrigeration cycle. To date, relatively few commercial installations have been made.
Generation of Electricity
Electricity can be generated by a variety of technologies that ultimately depend on the effects of solar radiation. Windmills and waterfalls (themselves very old sources of mechanical energy) can be used to turn turbines to generate electricity. Most existing windmill installations are relatively small, containing ten or more windmills in a grid configuration that takes advantage of wind shifts. In contrast, most electricity from hydroelectric installations comes from giant dams. Many of the sites suitable for large dams have already been tapped, especially in the industrialized nations, but during the 1970s small dams used years earlier for mechanical energy were retrofitted to generate electricity.
Large-scale hydro projects are still being pursued in many developing countries. The simplest form of solar-powered electricity generation is the use of an array of collectors that heat water to produce steam to turn a turbine. Several of these facilities are in existence, producing approximately 200 megawatts of power.
Other sources of sun-derived electricity involve high-technology options that remain unproven commercially on a large scale. Photovoltaic cells (see PHOTOELECTRIC EFFECT), which convert sunlight directly into electricity, are currently being used for remote locations such as orbiting space satellites, unattended railroad crossings, and irrigation pumps; but progress is needed to lower costs before widespread use is possible. The commercial development of still other methods seems far in the future. Ocean thermal energy conversion (OTEC) generates electricity on offshore platforms; a turbine is turned by the power generated when cold seawater moves from great depths up to a warm surface. Also still highly speculative is the notion of using space satellites to beam electricity via microwaves down to the earth.
Biomass
Fuels from biomasses encompass several different forms, including alcohol fuels (mentioned earlier), dung, and wood. Wood and dung are still major fuels in some developing countries, and high oil prices have caused a resurgence of interest in wood in industrialized countries. Almost half of the households in Vermont, for example, are estimated to heat partially with wood. Researchers are giving increasing attention to the development of energy crops, although there is some concern that heavy reliance on agriculture for energy could drive up food prices.
Current Status
The total amount of solar energy now being used may never be accurately estimated, because some sources are not recorded. In the early 1980s, however, two main sources of solar energy, hydroelectric energy and woodburning, contributed more than twice as much as nuclear energy to the world energy supply. Nevertheless, these two sources are limited by the availability of dam sites and the availability of land to grow trees, so the future development of solar energy will depend on a broad range of technological advances. Estimates of the likely contribution of solar energy to the U.S. energy balance in the year 2000 range from the 1980 level of about one-twelfth up to one-fifth of the total.
GEOTHERMAL ENERGY
Geothermal energy (see GEOTHERMICS) is based on the fact that the earth is hotter the deeper one drills below the surface. Such energy derives from steam trapped deep in the earth. Brought to the surface, it will drive a turbine to produce electricity. Alternatively, water can be heated by pumping it through deep hot rocks. Theoretically limitless, in most habitable areas of the world this subterranean energy source lies so deep that drilling holes to tap it is very expensive.
ENERGY EFFICIENCY IMPROVEMENTS
Transportation
Industry
Buildings
Three types of possible energy conservation practices may be described. The first is curtailment, that is, doing without—for example, closing factories or staying home instead of taking trips. The second is overhaul, that is, changing the way people live and the way goods and services are produced—for example, outlawing further suburbanization or switching to less energy-intensive materials in production processes. The third involves the more efficient use of energy, that is, adjusting to higher energy costs—for example, investing in cars that go farther per unit of fuel, capturing waste heat in factories, and insulating houses. This last alternative is most acceptable to governments and society in general.
By 1980 many people had come to recognize that increased energy efficiency could help the world energy balance in the short and middle term, and that productive conservation should be considered as no less an energy alternative than the energy sources that have been described. Substantial energy savings began in the 1970s, and a further 30–40 percent appeared possible without dramatically affecting people’s lives. A number of obstacles stand in the way, however. One major roadblock to productive conservation is its highly fragmented and unglamorous character; it requires hundreds of millions of people to do mundane things such as turn off lights and keep tires properly inflated. Another barrier has been the price. The cost of gasoline in the U.S. in 1990 was only slightly higher than it was in 1970, if inflation is factored in. This figure is one-third that charged in Europe. Low energy prices make it difficult to convince people to invest in energy efficiency. A third obstruction is the lack of information and adequate money for consumers to make energy-conservation investments.
Over time energy efficiency improvements more than pay for themselves, but they do require diverting investments in the short term, which is more difficult for some sectors of the economy than for others. Major areas for such improvements are described below.
Transportation
Whereas transportation uses only one-fourth of U.S. total energy, it accounts for 60 percent of U.S. oil consumption. Cars built in other countries have long tended to be more efficient than those built in the U.S., partly because of the pressures of heavy taxes on gasoline and on large engines in those countries. In 1975 the U.S. Congress passed a law that mandated doubling the fuel efficiency of new cars by 1985. This law, coupled with gasoline shortages in 1974 and 1979 and substantially higher gasoline prices (especially since 1979), caused the average efficiency of all U.S. cars to improve about 40 percent between 1975 and 1990; however, much of this improvement has been offset by dramatic increases in the number of cars on the road. In 1990 federal legislation enforcing stricter exhaust-emissions controls prompted automakers to step up the development of vehicles that use batteries and other alternative energy sources to run more cleanly and efficiently. The federal government has encouraged and helped to subsidize two other transportation modes: ride sharing (either van or car pools) and public transportation. These can be highly efficient, but the sprawling character of many U.S. cities can make their use difficult. See also AUTOMOBILE INDUSTRY.
Industry
Profit-conscious business managers are increasingly emphasizing the modification of products and manufacturing processes to save energy. The industrial sector, in fact, has recorded more significant improvements in efficiency than either the residential or the transportation sector. Improvements in manufacturing can be classified into three broad, somewhat overlapping, categories: improved housekeeping—maintaining furnaces and adjusting lighting; recovery of waste —recovering heat and recycling waste by-products; and technological innovation—greatly redesigning products and processes to embody more efficient technologies.
Buildings
In the 1950s and ’60s efficient energy use was often neglected in constructing buildings and houses, but the high energy prices of the 1970s changed that. Some new office buildings built in 1980 use only a fifth of the energy used in buildings constructed just ten years earlier. Techniques to save energy include designing and siting buildings to use passive solar heat, avoiding overlighting, and using better insulation and storm windows. A "life-cycle" approach, which takes into account the total costs over the entire life of the building, rather than merely the initial construction cost or sales price, is encouraging greater efficiency. Also, the retrofitting of old buildings, in which new components and equipment are used in existing structures, has been successful. The use of computers in design and in heating and lighting systems has also increased energy efficiency in buildings and homes. R.St. & D.Y.; REV. BY H.L.
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WARNING:Only for educational purposes.Author has nothing to do with content .Author does not own copyrights.
