Energy in Society
ENERGY plays a unique and critical role in the world; no activity of any kind (no "work") can take place without the movement or conversion of energy.
Energy in Society
ENERGY plays a unique and critical role in the world; no activity of any kind (no "work") can take place without the movement or conversion of energy. Energy use in society is a flow that begins with a source (eg, COAL, URANIUM, PETROLEUM, the SUN) and passes through several intermediate processes for refinement or conversion to a different form (eg, electricity, diesel oil, methane), finally reaching a home, vehicle or industrial plant, where it is introduced into a consuming device (eg, furnace, motor).
In between are imports, exports and losses of various kinds, including the energy needed to operate the energy system itself. The final consumer does not want energy as such but only the services it can provide, services that are not measured in litres or joules but in warmth, motion, sound, etc. Although higher-income countries, provinces and people tend to use more energy, energy use does not necessarily indicate standard of living; efficient energy use produces more services from a given amount of resources.
Two thermodynamic laws govern all aspects of energy use. The first states that a given system will always contain the same amount of energy. The second states that every time an amount of energy is used its quality declines; what we consume is the ability to get useful work from energy, not the quantity of the energy itself. Hence, we keep track of both the quantity and quality of the energy we use. Quantity is measured in familiar units, such as litres (L) of oil, kilowatt-hours (kWh) of electricity, and tonnes (t) of coal, all of which can be converted to one standard unit of energy content, the joule (J).
Quality is more difficult to measure: scientific measures do exist, but for many purposes it is sufficient to think of higher-quality energy as being hotter or denser (ie, containing much energy in a small volume - eg, gasoline) or more versatile (eg, electricity). The market value of high-quality energy is generally higher. Energy conservation involves not only saving quantities of energy but also ensuring that high-quality forms are used only when necessary. Thus, dense fuels are most useful for transportation; electricity is most appropriate for lighting, electronics and motors; and heating buildings requires only low-quality energy because the temperatures of buildings are raised by relatively small amounts.
Measuring Energy Efficiency
There are many ways to measure the efficiency with which energy is used. First-law efficiency indicates how much energy is being used compared with the service provided (eg, L of gasoline per 100 km of car travel). Calculations using this measure suggest that the Canadian economy may be 40% efficient. A second measure, second-law efficiency, relates the energy used to obtain a service to the theoretical minimum needed under ideal conditions. Estimates using this measure suggest that the Canadian economy is less than 10% efficient (or as low as 1-2% if materials use and RECYCLING are considered).
A third measure of efficiency does not depend directly on thermodynamics but on economics. Cost effectiveness relates the dollar value of inputs to the energy services obtained. This type of measure is needed for decisions in which energy must be balanced against other economic activities (eg, adding more insulation versus buying more fuel to warm a building). Calculations indicate that most sectors of the economy spend twice as much on energy (ie, they are only half as cost effective as they could be).
Determining Energy Use
Four sets of factors determine how much energy is used in a society. First are demographic and geographic factors: other things being equal, the greater the population, the bigger the area and the colder the climate, the more energy will be used. Thus Canada's relatively small, dispersed population requires that a lot of energy be used for transportation. Canada is colder than most countries, although new building techniques are conserving energy.
The second set of factors determining energy use is economic. There is no direct relationship between national income and energy use, and countries with similar levels of per capita income can use different amounts of energy. However, higher-income countries with more industry do use more energy than poorer, less-industrialized ones.
In Canada industry is concentrated in the primary sectors (pulp and paper, smelting and refining, agriculture), which tend to use more energy per dollar value of production than manufacturing or service industries do. Energy use also reflects the availability and cost of energy resources. Historically, for example, Canada and the US have had a greater abundance of relatively low-cost energy (eg, large, easily accessible waterfalls and, of course, petroleum) than most other industrial countries, and hence they have used it extensively.
Consumers, private and industrial, tend to use less energy as its price goes up. This effect, called price elasticity, has been estimated to lie between -0.5 and -1.2, which means that for each 10%increase in the price of energy, use will drop 5 to 12%. The more essential some amount of energy is, the lower will be its price elasticity. For example, price elasticity would be very low for the amount of energy needed to bring the temperature inside a house to, say, 60°, but likely much higher for the additional amounts needed to keep the house warmer.
The third set of factors is technological. For most of industrial history, energy use per dollar of output has declined. However, for about 25 years from the end of WWII until the 1970s, which was a period of exceptionally low energy prices, rather little attention was paid to the technology of energy use. Examples of this neglect occurred in housing and the American automobile, and others occurred throughout industry. With the rise in prices and what were then misconceived fears of shortages, many old techniques involving more efficient energy use were reintroduced and research into new ones began (see SCIENTIFIC RESEARCH AND DEVELOPMENT). For example, Canadians have become world leaders in constructing energy-efficient buildings. Typical single-family homes built around 1973 require about 175 gigajoules (GJ = 109 J, roughly the energy content of 4500 L of heating oil) for heating each year.
Homes being built today to the federal government's R-2000 design use 40-50 GJ annually; the most efficient ones (modelled on the Saskatchewan Conservation House) need only 15 GJ. In 1973 typical high-rise office buildings required 600 kWh per m2 each year for operation; many being built since then have cut this to 200 kWh. The Gulf Canada Square tower in Calgary requires only 125 kWh, and a federal office building in Scarborough, using underground storage and solar panels, has cut the figure to 20 kWh.
The fourth set of factors involves lifestyles. For example, some people choose to live in smaller houses or in apartments, to buy more efficient cars or use public transit, and to buy goods in returnable or recyclable containers, thereby using less energy. North American lifestyles have tended to go in the opposite direction, towards "conspicuous consumption," although some trends seem to be changing.
Measurement of Energy Use
Energy use is a flow that can be measured at various points and in various ways. Primary energy consumption is measured at the point of production; it includes the energy required for production but has definitional problems. Tertiary consumption, on the other hand, indicates the amount of energy finally available for, say, heating a room or turning the wheels of a vehicle after deducting efficiency losses in the furnace or motor. Tertiary energy consumption is conceptually important but difficult to measure. For many purposes, the most useful and straightforward results are given by secondary energy consumption, which is measured at the point of purchase of the consumer.
Statistics on secondary energy use typically are divided according to the form of energy used (eg, gasoline, electricity) and according to the sector in which it is used (eg, residential, commercial, industrial, transportation). Completely separate from this secondary energy is use in the energy supply sector, to cover the fuel or electricity consumed or lost in energy production, conversion, transportation and transmission. In past years energy use by the energy supply sector was about 20% as great as use by the rest of the economy (secondary energy use). However, with the shift to more distant ("frontier") oil and gas resources, heavier oils and more sour (higher SULPHUR) natural gas, the energy requirements to produce energy are rising. Depending upon the value given to primary electricity (mainly HYDROELECTRICITY and nuclear power), energy use by the energy supply sector is now closer to one-third as great as secondary energy use.
Modern approaches to energy analysis and the most effective method for energy forecasts depend on a breakdown according to the use made of the energy. Heating and cooling include all space and water heating plus low-temperature process heat. Higher temperature heat is used only in industry. Electricity-specific uses such as electronics, lighting or appliances depend on the properties of electricity. Liquid fuels are uniquely valuable for portable uses such as transportation.
This breakdown takes account of quality and shows, for example, that most Canadian energy requirements are for heat at various temperatures (55% of total use, 75% of industrial use) and that electricity-specific uses represent little more than 13% of the total. However, 2 adjustments must be made to the energy data. First, it must allow for nonenergy products (eg, plastics, fertilizers, construction materials, lubricants) produced from energy raw materials. For oil and gas, the required adjustment is 10-15% of total domestic consumption, but this has been rising over time; for coal the adjustment is 15-20%, with most of it used as coking coal in smelters and blast furnaces. (Canada also exports a great deal of coking coal, but exports are excluded from these consumption figures.) The other adjustment involves the energy that does not pass through an organized market, such as wood sold at a rural lot. Statistics typically report only commercial energy. This means, for example, that wood as a residential fuel never fell as low as indicated by Canadian statistics. More importantly, it means that energy use in developing countries, many of which rely heavily on traditional fuels, such as twigs and branches, agricultural wastes and dung, is much larger than shown in most statistics.
A statistical problem particularly important to Canada involves ELECTRIC POWER, a form of energy that can be manufactured from diverse sources such as falling water, burning coal or controlled nuclear reactions, each with its own rate of conversion (the difference between the energy content of the source input and that of the electricity output). The simplest approach for preparation of energy-use statistics is to ignore the source of the electricity and convert directly from electrical output to joules (3.6 MJ per kWh).
However, in most international and some Canadian statistics, electricity is converted to energy units expressed as the amount of coal or oil that would be needed to produce it, which, for thermodynamic reasons, is about 3 times as large. This practice leads to the calculation that 35% of Canada's energy is used in the form of electricity, when the correct figure is about 17%. If electricity in Canada were used only for those specific applications where it is truly efficient, the figure would be further reduced to the 13% described above.
Secondary Energy Use in 1994
Total secondary energy use in Canada in 1994 was approximately 7.0 exajoules (EJ = 1018J), including fuel wood and various wood wastes used for fuel in the forest industry, but excluding fuel and electricity use by the petroleum industry and pipelines. Ontario and Québec account for about three-fifths of this use. The levels of energy use per capita in these 2 provinces are about equal, but Ontario is well below Québec and most other provinces in energy use per dollar of provincial product (because Ontario has relatively more light manufacturing compared with primary industries). Other provincial variations follow mainly from geographic and economic differences. BC uses more energy in the forest industry and less for heating than elsewhere. The Atlantic provinces are the lowest per capita users of energy; the Prairie provinces are the highest.
International Energy Use
World energy use in the mid-1990s was about 365 EJ, or an average of about 69 GJ per capita, both up roughly 15% over the last decade. Variations around the average are large. Industrial countries typically use 150-200 GJ per capita; Canada uses 228 GJ per capita, down about 10% over the past 15 years; developing nations, 20-25 GJ per capita; and the poorest countries in Africa, 2.5 GJ per capita (commercial energy only; perhaps 5 times as much if traditional forms of energy are included). Energy use in less developed countries is dominated by household uses, which depend mainly on traditional fuels, with transportation taking the bulk of commercial energy; outside the cities, electricity is used for minimal lighting and pumping water for irrigation population, accounts for 2% of world energy use. It is often said that Canadians consume more energy per capita or per dollar of Gross Domestic Product than any other country, but international statistics tend to make Canada appear more energy-intensive than it actually is. For example, the manner in which the use of electricity is calculated overstates Canada's energy use. Our nonenergy exports contain about 25% more energy per dollar of trade than do our imports.
In addition, Canada exports a great deal of energy in the form of raw or semifinished goods. This "embodied" energy should in principle be counted against the country where steel, paper or aluminum is used. Despite these qualifications, Canada remains one of the world's most energy-intensive nations.
Changes in Energy Use
With growth in population, economy and income, Canadians have used more and more energy. Before WWII secondary energy use in Canada climbed at about 3% per year, but during the era of cheap energy after the war this rate climbed to 5% and higher. Such growth rates ended quickly with the energy crisis of 1973. Since then the rate has fallen, largely because of gains in efficiency. Between 1974 and 1980 energy use grew by an average of 2.3% annually; since then it declined still further to only 1.5% per year. Oil use has dropped by much more: fears of shortage and higher prices work against its use except for transportation or in regions where other heating fuels are unavailable or much more expensive.
Projections of future energy use abound, but one thing is striking: expectations of further energy use are falling. A 1973 report of the federal Department of Energy, Mines and Resources expected 4.5%annual growth; a 1976 report envisioned 3.7%; the 1980 NATIONAL ENERGY PROGRAM projected 1.9%; and a 1986 report from the staff of the National Energy Board expected 1.5-1.9%. By 1994, the federal energy department (now called Natural Resources Canada) was projecting that demand for secondary energy would grow by only 1.2% per year over the 2000-2020 period. The decline reflects partly lower expectations for economic growth but mainly the growing awareness for the potential for energy efficiency.
Since 1973 the energy required to produce a dollar of GDP in Canada has fallen by about 30%, a remarkable turn-around from the previous period. Although the decline has halted in the last few years, there is continued attention paid throughout the economy to end-use technology, to ways to use waste products and waste heat as sources of energy, and to techniques such as cascading and cogeneration in which the same quantity of energy is used for a series of services as it gradually declines in quality (eg, first for generation of electricity, then for high-temperature process heat, finally for space heating).
Even the lowest official projections may be too high. Some recent analyses begin with end-use demand for energy services (rather than energy supply, as in conventional analyses) and try to match the quality of energy supplied to end-use requirements. These studies are called "soft energy" studies because they emphasize smaller-scale, decentralized and environmentally less destructive means of providing energy. Soft energy studies show that it is possible to satisfy our needs for energy with only one-quarter or one-third as much energy as we now use, with significant economic savings and a halt to further CLIMATE CHANGE. Soft energy studies have been prepared for many nations, including Canada. Even in developing countries, where greater energy use (or, more accurately, greater use of high-quality forms of energy) is clearly essential to improving the quality of life, soft energy analyses show much more moderate increases than conventional studies.
Canada's rate of energy use will be determined in part by physical laws and technology, but to a greater extent by individual choices and government policies. The limits to energy production and use are set by physics and geology, but those limits are wide; within them the rates actually achieved are mainly determined by politics and economics. As values change, CONSERVATION is playing a greater and greater role in ENERGY POLICY. No small part of that value change is related to growing public demand for protection of the ENVIRONMENT. Energy use, no matter how efficient, inherently involves environmental degradation, and in recent years the adverse impacts ranging from local smog to global climate change have become major issues in Canada and most other nations. The most important limits to energy use may not lie in the limited availability of the Earth to provide energy resources, but rather in its limited capacity to assimilate energy wastes. That environmental concerns will play a greater role in future energy policy is certain; how much greater is very uncertain.
Residential uses account for 20% of total secondary use in Canada. Nearly 85% of this energy is used for space and water heating, while the remaining 15% represents all the other household appliances, which generally run on electricity. Coal and wood, which used to provide much residential heating, have declined in favour of more convenient fuels. Use of coal remains negligible but wood now has an 6% share. Other fuels for residential heating are oil, 12% (1980, 46%), natural gas, 47% (1980, 38%) and electricity, 34% (1980, 14%). Clearly, use of oil products has declined substantially in the face of higher prices and government subsidy programs supporting other forms. It is difficult to separate residential from agricultural uses of energy, so the 2 are often combined, although agriculture is more of an industry. These statistics show that energy use on farms accounts for 3% of secondary energy use in Canada, about twice this on the Prairies.
Commercial uses include energy for offices, schools, hospitals, stores and hotels, and account for 13% of Canadian energy use, of which two-thirds (1980, three-quarters) is used for heating and cooling buildings and for water heating and one-third for electricity-specific uses. Energy for this sector is increasingly supplied by natural gas and electricity, each of which provides about 43% of sectoral use.
Industrial uses, including primary industries, manufacturing and construction, account for more energy than any other sector - 36% (1980, 37%) of the total. Despite the lack of significant change in the past 20 years, most projections show this share growing toward one-half.
In contrast to other sectors, industry uses energy of all qualities and forms. Nearly three-quarters of industrial energy is used as heat, some 40% for temperatures above 260° C. Energy forms are divided among oil products, 18% (1980, 36%), natural gas, 34% (1980, 28%), and electricity, 25% (1980, 21%). Apart from electric utilities and home heating, the industrial sector is the only significant user of coal and wood for energy - 6% and 17% respectively (1980, 8%each).
Only 7 industries - pulp and paper, chemicals, primary metals, food and beverage, mining, industrial minerals and construction - accounted for nearly 75% of all industrial energy use. The first 3 alone accounted for about half of industrial energy use and two-thirds of all high-temperature heat and perhaps three-quarters of all water used by industry. The subsectors vary widely in the forms of energy used: for example, the chemicals and petrochemicals industries use large volumes of oil and gas as fuel and also as inputs to produce plastics and other nonenergy products; the aluminum industry is a particularly heavy user of electricity; the forest industries use their own wood wastes as sources of energy (thus simultaneously reducing solid wastes and WATER POLLUTION).
Transportation uses account for more energy use in Canada than in most other countries: 29% (almost unchanged from 1980) of total use and, more significantly, nearly 70%(1980, half) of oil use. Automobiles and light trucks account for 53% of transportation use (14% of Canada's total energy use); larger trucks take 27% and buses 1%; therefore, road modes use a total of 81%. The remaining modes are much lower: air, 9%; marine, 5.5%; and rail, 4.5%. However, in some provinces the positions vary; eg, in Newfoundland marine rises to second place behind road use.
About half of transportation energy is used within urban areas, the remainder between cities. The transportation sector is unique in depending almost exclusively on one form of energy, liquid fuel (primarily gasoline, diesel oil and aviation turbo fuel), derived from one source, oil; a tiny fraction is electricity, used for urban public transit. A small number of vehicles run on propane or compressed natural gas; even fewer use methanol (a form of alcohol derived mainly from natural gas). Auto engines must be adapted to use these fuels. By contrast, many gasoline service stations now provide motorists with the option of gasoline that, depending upon the season, contains 5-10% of ethanol (another form of alcohol derived either from natural gas or from corn and other crops with a high sugar content); this blend can be used by any engine designed for gasoline.
Robert Bott et al, Life After Oil: A Renewable Energy Strategy for Canada (1983); David B. Brooks, Zero Energy Growth for Canada (1981); José Goldemberg et al, Energy for a Sustainable World (1988); Florentin Krause et al, Energy Policy in the Greenhouse (1992); National Resources Canada, Energy Efficiency Trends in Canada (1996).