Wind energy is one of the most cost-effective solutions to traditional resources like coal, oil, or nuclear power. World growth cannot continue without energy constraints at rates near historic highs. In the first few decades some increase results in dependence on oil and gas, but this increase need be no more than is readily accommodated by world excess capacity. The main advantage is the low cost and environmentally friendly design of collectors.
The threat of future shortages of liquid and gaseous fossil fuels can be relieved to some extent by converting coal to oil and gas. The liquefaction and gasification processes for coal may soon be as economical as obtaining liquid and gaseous fuels from conventional sources, and both processes seem likely to be used commercially within the 1970s. Reliance on coal for all fossil fuel needs would of course shorten the life expectancy of our coal reserves considerably. One possible alternative is the oil shales, which constitute a potential energy resource much larger even than coal (Manwell and Rogers 43).
Hydroelectric energy and the energy of the wind and tides will always be available. The rate at which these energy sources can be exploited, however, is limited by the global flow of energy in the form of falling water, wind, and tides at any given time. It is also limited by the number of sites where these processes can be exploited economically. Power is the rate at which energy flows or is used. Continuous energy sources, such as the water cycle, are usually characterized in terms of power — say in kilowatts — although they could easily be characterized by the amount of energy flowing per day or per yea (Beggs 83).
The world’s potential production of hydroelectric power is roughly half of the amount of power now being produced by fossil fuels. There are, however, serious problems in utilizing it to the utmost. Much of the potential lies in international conventions, where the power could not be used unless those countries were industrialized; global ecological factors and the inability of the international conventions, to mobilize capital and high-grade resources will impede industrialization in most of them. Furthermore, reliable hydroelectric power depends on dams, which under present conditions of technology are temporary structures.
In a few hundred years — sometimes more, sometimes less, depending on the river — their reservoirs fill with silt and become useless. Thereafter, power production from the waterfall occupying the dam site hinges on the daily and seasonal variations of river flow. Finally, there is an important aesthetic question: do we wish to impound and control all of the wild rivers of the Earth? Unfortunately, tidal power comprises only a minute fraction of all potential water power, and will presumably never be of more than local importance. Wind energy has the disadvantages of low concentration and of being unpredictable and intermittent in most locations (Birkeland 41).
There is some dispute about the exploitable power potential of the heat of the Earth’s interior (geothermal energy). Some experts say that geothermal energy will never supply more than a very small fraction of civilization’s energy needs. Others are much more optimistic. Geothermal energy is already important in a few countries such as Iceland, New Zealand, and Italy. A major uncertainty is the lifetime of the underground reservoirs of superheated water or steam that constitute the exploitable form of geothermal energy. Of course, ways to tap the heat of the Earth without relying on these reservoirs may yet be developed (Beggs 29).
For many years men have speculated about the sun as a source of nondepletable power. Large-scale utilization of wind energy presents serious technological problems, arising mainly from intermittency (no sunshine at night, little on cloudy days, less in winter than summer) and the low concentration of energy.
The collecting device for an electric generation plant with a capacity of 1,000 megawatts (enough power to supply electricity to a city of perhaps 750,000) would have to cover an area of about 16 square miles, assuming the solar-to-electric conversion efficiency to be 10 percent. Several recent studies have indicated that higher efficiencies and, hence, smaller collector areas are possible. Electricity generated in large wind power plants will not necessarily be prohibitively expensive, contrary to the claims of some critics (Blair 88).
Of course, the greatest potential of wind power may be in dispersed uses — such as air conditioning and space heating — that take advantage of the fact that the sun has already distributed the power for us. Space heating, water heating, and air-conditioning for individual buildings using simple wind collectors mounted on roofs would probably be economically competitive with conventional electric units in many parts of the United States today. Because of the wind patterns in the eastern Pacific and the ring of mountains surrounding the Los Angeles Basin, it is an ideal place for the formation of inversions, usually at about 2000 feet above the floor of the basin. They occur there on about seven out of every 16 days (Dobson 82).
As summer approaches, the weather warms, the longer days mean longer periods of insulation, and the brisk spring winds subside. Under these conditions, the surface waters warm rapidly, expand, and become lighter than the lower waters. Although the wind may continue to blow, its contribution to the mixing of lake waters diminishes, for now, the thermal density gradient opposes the energy of the wind. With the progression of the summer season, the resistance to mixing between two layers of different densities (resulting from increased temperatures) becomes greater than the force of winds–the significant density differences having been built up during periods of summer calm (Douthwaite 82).
Market development and operating experience are now encouraged by renewable energy tax credits, which are expiring. Financial incentives to continue these developments will be needed. Modern materials and techniques make possible collector surfaces that absorb heat readily but emit little of it. Such devices, technically available, are not needed for low-temperature space heat. That is more easily provided by passive wind design and super-insulation (Tylecote 55).
Other low-temperature heat needs (residential and commercial hot water; industrial low-temperature heat) can be supplied by direct wind collection, with backup systems selected according to the relative abundance of other renewable sources. Geothermal heat systems may compete more effectively in much of Europe once the resource is more thoroughly assessed (Blunden and Reddish, 77).
In other renewable energy technologies, photovoltaics and wind industrial process heat can benefit from basic research in materials. In areas with heavy prospective air-conditioning loads, photovoltaic electricity is especially helpful, being well correlated with the load. Windunits that use heat to drive the air-conditioning process also may be available. The foregoing discussion has attempted to demonstrate that renewable energy resources are numerous, widespread, and large. In addition to wind heat, photovoltaic electricity, and biomass, available everywhere, nearly every Third World nation has at least two of the other renewable energy sources: wind, geothermal, tides, hydroelectricity, or wind ponds.
The most productive applications are in areas with high insolation and proximity to hydroelectric or wind installations, i.e., most of the Third World. Other wind-electric technologies also may be competitive. Hot water, space heat where needed, and much industrial process heat lend themselves to wind supply. Wind energy will have a positive impact on climate change and global warming (through reduced emissions) and will support economic growth (Brown 92).
Wind energy is good because it is cheap and is available in all nations, even though some have short winter days and overcast skies. Wind energy is a renewable source while coals and oil are exhaustible natural resources. Thus the main problem is that wind electricity is thought to be intermittent and therefore unusable in volume without enormous storage capacity requiring a technological breakthrough in battery or other storage.
There are several reasons why international agreements on greenhouse gases are so difficult to achieve. Controlling these gases requires a massive change in economic priorities, including technology-forcing features and alternative sources of energy. In contrast, the prevention of ozone depletion is relatively easier because it requires less economic and technological change. Ozone-depleting chemicals were produced mainly by a relatively small number of rich nations. Moreover, all nations will not be affected to the same degree if global warming occurs (Blunden and Reddish, 77).
Some nations, like the United States, have actively shown their commitment to comprehending the events that control the “greenhouse effect.” They do this by funding research that aims to minimize the scientific uncertainties that presently exist concerning the magnitude of projected temperature changes for different global regions. However, meaningful efforts to minimize global climatic modifications require binding international laws. Although virtually all nations have expressed interest in international negotiations concerning minimizing global warming, as with so many other major environmental concerns facing international policymakers, the timing and fortitude of their responses are shortsighted. The importance of the world’s environmental movement should not be overlooked (Blunden and Reddish, 77).
In sum, most environmental agreements are not yet subject to international adjudication, and other mechanisms may be used to enforce them. Some of these agreements have been enforced using trade measures, pressures from non-governmental organizations, and debt-for-nature swaps. International commitment to protecting the global commons, an effort that has attracted the attention of both public and private decision-makers, has demonstrated the value of widespread cooperation in the affairs of government. The carrying-capacity principle states that as the population approaches the optimum level of sustainable size, or carrying capacity, environmental resistance becomes greater and greater. The carrying capacity is determined by available resources and other limiting factors in a given area.
The difference between biotic potential and actual population growth is a measure of environmental resistance. An ideal wind power satisfies its needs without diminishing the prospects of surviving in space and time. Evaluated by this measure, contemporary society fails to meet this criterion. The decomposers in human systems are not as developed as in natural ecosystems. Ecosystems rely on their decomposers to break down dead plants and animals and to recover or recycle waste materials.
Works Cited
Manwell, J. F., Rogers, A. L. Wind Energy Explained: Theory, Design and Application. Wiley, 2002.
Beggs, C. Energy: Management, Supply and Conservation, Butterworth-Heinemann, Oxford, 2002.
Birkeland, J. Design for Sustainability, Earthscan, London, 2–2.
Blair, I. ‘Green products’, in Charter, M. (ed.) Greener Marketing: a Responsible Approach to Business, Geenleaf Books, London, 1992.
Blunden, J. and Reddish, A. (eds) Energy, Resources and Environment, Hodder and Stoughton/Open University Press, London, 1992.
Brown, L. Wind Power: the Missing Link in the Bush Energy Plan, Earth Policy Alert, Earth Policy Institute, Washington DC, 2001.
Dobson, A. Green Political Thought, Routledge, London, 1995.
Douthwaite, B. Enabling Innovation, Zed Books, London., 2002.
Tylecote, A. The Long Wave in the World Economy, Routledge, London, 2002.