| Environmental Concerns With Electricity Generation |
Article Index for Environmental |
Shopping Concerns |
Website Links For Environmental |
Information AboutEnvironmental Concerns With Electricity Generation |
| CATEGORIES ABOUT ENVIRONMENTAL CONCERNS WITH ELECTRICITY GENERATION | |
| renewable energy | |
| landscape | |
| national electric power policy | |
| power stations | |
|
The efficiency of some of these systems can be improved by cogeneration ( Combined Heat And Power ) methods. Process steam can be extracted from steam turbines. Waste heat produced by thermal generating stations can be used for space heating of nearby buildings. By combining electric power production and heating, less fuel is consumed, thereby reducing the environmental effects compared with separate heat and power systems. FOSSIL FUELS ]] See Also: Fossil fuel Most electricity today is generated by burning fossil fuels and producing Steam which is then used drive a Steam Turbine that, in turn, drives an Electrical Generator . Such systems allow electricity to be generated where it is needed, since fossil fuels can readily be transported. They also take advantage of a large infrastructure designed to support consumer Automobile s. The world's supply of fossil fuels is large, but finite. Exhaustion of low-cost fossil fuels will have significant consequences for energy sources as well as for the manufacture of Plastic s and many other things. Various estimates have been calculated for exactly when it will be exhausted, but new sources of fossil fuels keep being discovered. More serious are concerns about the emissions that result from Fossil Fuel Burning . Fossil fuels constitute a significant repository of Carbon buried deep under the ground. Burning them results in the conversion of this carbon to Carbon Dioxide , which is then released into the atmosphere. This results in an increase in the Earth's levels of atmospheric carbon dioxide, which enhances the Greenhouse Effect and contributes to Global Warming . The linkage between increased carbon dioxide and global warming is nearly universally accepted, though fossil-fuel producers vigorously contest these findings. Depending on the particular fossil fuel and the method of burning, other emissions may be produced as well. Ozone , sulfur dioxide, NO2 and other gases are often released, as well as Particulate Matter . Sulfur and nitrogen oxides contribute to Smog and Acid Rain . In the past, plant owners addressed this problem by building very tall Flue Gas Stacks , so that the pollutants would be diluted in the atmosphere. While this helps reduce local contamination, it does not help at all with global issues. Fossil fuels, particularly Coal , also contain dilute Radioactive material, and burning them in very large quantities releases this material into the environment, leading to low levels of local and global Radioactive Contamination , the levels of which are, ironically, higher than a Nuclear Power Station as their radioactive contaminants are controlled and stored. Coal also contains traces of toxic heavy elements such as Mercury , Arsenic and others. Mercury vaporized in a power plant's Boiler may stay suspended in the atmosphere and circulate around the world. While a substantial inventory of mercury exists in the environment, as other man-made emissions of mercury become better controlled, power plant emissions become a significant fraction of the remaining emissions. Power plant emissions of mercury in the United States are thought to be about 50 tons per year in 2003, and several hundred tons per year in China. Power plant designers can fit equipment to power stations to reduce emissions. According to Environment Canada: "The electricity sector is unique among industrial sectors in its very large contribution to emissions associated with nearly all air issues. Electricity generation produces a large share of Canadian nitrogen oxides and sulphur dioxide emissions, which contribute to smog and acid rain and the formation of fine particulate matter. It is the largest uncontrolled industrial source of mercury emissions in Canada. Fossil fuel-fired electric power plants also emit carbon dioxide, which may contribute to climate change. In addition, the sector has significant impacts on water and habitat and species. In particular, hydro dams and transmission lines have significant effects on water and biodiversity."1 Coal mining practices in the United States have also included Strip Mining and Removing Mountain Tops . Mill tailings are left out bare and have been leached into local rivers and resulted in most or all of the rivers in coal producing areas to run red year round with sulfuric acid that kills all life in the rivers. NUCLEAR POWER ]] See Also: Nuclear safety Nuclear power Nuclear power has raised much public concern. Under normal operation, a nuclear power plant releases very little contamination of any sort to the environment. It does produce Radioactive Waste of several sorts. Moderate amounts of low-level waste are produced; this can be disposed of simply by placing it somewhere it won't be disturbed for a few years. However, a relatively small amount (perhaps a ton a year from a large nuclear power plant) of high-level waste is produced, and this poses a significant disposal problem. It can be expected to be dangerous for tens or hundreds of thousands of years (Taking 10,000 years to decay to activity levels below that of the original ore), so extremely secure disposal methods must be found. Currently, most such waste is stored in temporary storage facilities which require constant care and attention. Several methods have been suggested for final disposal of the waste, including deep burial in stable geological structures, transmutation, and removal to space. Some nuclear reactors, in particular the Integral Fast Reactor , have been proposed that use a different Nuclear Fuel Cycle that avoids producing waste containing long-lived radioactive isotopes. Accidents at nuclear power plants pose a risk of severe environmental contamination. The Chernobyl Accident at an RBMK reactor, for example, released large amounts of Radioactive Contamination , killing many and rendering a large area of land unusable for the next few centuries. However, the power plant at Chernobyl was built with minimal concern for safety; modern nuclear power plants are much less likely to have such problems. The potential for such an accident still exists; however, many citizens are still concerned about the use of nuclear power. But their concerns should be weighed against the need to address the threats posed by climate change and the opinions of the broader community. This danger has received significant coverage in the popular press, so the public has a very strong fear of nuclear power (by contrast, the radioactive contamination due to coal burning is virtually unknown, as are most of the hazards of other methods of electrical power generation). Nuclear power can also pose the risk of Nuclear Proliferation . Fission products can be reprocessed out of spent reactor fuel and diverted to a Weapons Program , or a reactor can be used to produce weapons materials through Transmutation by direct irradiation by Neutron s. TIDAL POWER See Also: Tidal power In regions such as the Bay Of Fundy with very large tidal swings, Tidal Power Plants can be built to extract electrical power from the tidal motion. Tidal power is also renewable, in the sense that it will continue for as long as the Moon orbits the Earth. However, it has environmental problems similar to those of hydroelectric power. A tidal power plant usually requires a large dam, which can endanger ecosystems by restricting the motion of marine animals. Perhaps more seriously, a tidal power plant reduces or increases the tidal swing, which can severely disrupt ecosystems which depend on being periodically covered by water; resulting changes in fisheries or shellfish beds may result in adverse economic effects. Certain proposed tidal power plants in the Bay Of Fundy would increase the tidal swing by an estimated 50 cm as far south as the coast of Maine (where the tidal swing is not particularly large now). BIOMASS See Also: Biomass Electrical power can be generated by burning anything which will combust. Some electrical power is generated by burning crops which are grown specifically for the purpose. Usually this is done by fermenting plant matter to produce Ethanol , which is then burned. This may also be done by allowing organic matter to decay, producing Biogas , which is then burned. Also, when burned, wood is a form of biomass fuel. Burning biomass produces many of the same emissions as burning fossil fuels. However, growing biomass captures carbon dioxide out of the air, so that the net contribution of the cycle to global atmospheric carbon dioxide levels is zero. The process of growing biomass is subject to the same environmental concerns as any kind of Agriculture . It uses a large amount of land, and Fertilizer s and Pesticide s may be necessary for cost-effective growth. Biomass that is produced as a by-product of agriculture shows some promise, but most such biomass is currently being used, for plowing back into the soil as fertilizer if nothing else. WIND POWER E-70 Wind Turbine ]] See Also: Wind turbine Wind power Wind power extracts electricity from the flow of air over the surface of the earth. Wind power stations generally consist of large "wind farms", fields of large Windmill s in locations with relatively high winds. A primary publicity issue regarding wind turbines are their older predecessor, such as the turbines located in California. These older, smaller, wind turbines are rather noisy and densely located, making them very unattractive to the local population. The turbines need constant maintenance, and result in bird deaths due to their high number of revolutions per minute. The downwind side of the turbine does disrupt local low-level winds. Modern wind turbines have overcome these constraints however, and have evolved in to a highly efficient and attractive energy source. Many homeowners in areas with high winds and expensive electricity set up small windmills to reduce their electric bills. A modern wind farm, when installed on agricultural land, has one of the lowest environmental impacts of all energy sources: Why Australia needs wind power
Landscape and heritage issues may be a significant issue for certain wind farms. However, when appropriate planning procedures are followed, the heritage and landscape risks should be minimal. Some people may still object to wind farms, perhaps on the grounds of aesthetics, but their concerns should be weighed against the need to address the threats posed by climate change and the opinions of the broader community.[http://www.tai.org.au/documents/dp_fulltext/DP91.pdf Wind Farms The facts and the fallacies] GEOTHERMAL POWER See Also: Geothermal power Geothermal energy is the heat of the Earth, which can be tapped into to produce electricity in power plants.Warm water produced from geothermal sources can be used for industry, agriculture, bathing and cleansing. Where underground steam sources can be tapped, the steam is used to run a steam turbine. Geothermal steam sources have a finite life as underground water is depleted. Arrangements that circulate surface water through rock formations to produce hot water or steam are, on a human-relevant time scale, renewable. While a geothermal power plant does not burn any fuel, it will still have emissions due to substances other than steam which come up from the geothermal wells. These may include Hydrogen Sulfide , and carbon dioxide. Some geothermal steam sources entrain non-soluable minerals that must be removed from the steam before it is used for generation; this material must be properly disposed. Any (closed cycle) steam power plant requires cooling water for condensors; diversion of cooling water from natural sources, and its increased temperature when returned to streams or lakes, may have a signifiant impact on local ecosystems. SOLAR POWER See Also: Solar Power Solar power, which is a renewable source of energy, has been used as an alternative to fossil fuels, primarily in Germany (where the Government offers financial incentives) and in areas with an abundant amount of sun. Solar power works by converting the sun's radiation into DC power by use of Photovoltaic cells. This power can then be converted into the more common AC power. Solar power offers a viable alternative to fossils fuels for its cleanliness and supply. Its negative impact on the environment lies in the creation of the solar cells (which are made of primarily silicon and the extraction of this silicon requires the use of fossil fuels) and the storage of the energy (which usually requires Lead-Acid batteries). It should be noted that solar power carries an upfront cost to the environment via production, but offers clean energy throughout the lifespan of the solar cell. NEGAWATT POWER See Also: Negawatt power Negawatt power is a way of supplying additional electrical energy to consumers without increased generation capacity at around half the cost of large scale generation. Whilst related to and utilising consumption efficiencies it differs in scale and market behaviour. This virtual generation method can supply decades of growth of supply in place of generation thus reducing environmental impacts of generation. Put simply it costs less to increase available supply by improving efficiency (and therefore reducing consumption) than by increasing plant generation capacity. SEE ALSO
REFERENCES
EXTERNAL LINKS
|
|
|