Hydroelectric dams

There are many benefits for using hydro resources to produce electricity. First, hydropower is a renewable resource oil, natural gas, and coal reserves may be depleted over time. Second, hydro resources are indigenous. A country that has developed its hydroelectric resources does not have to depend on other nations for its electricity hydroelectricity secures a country s access to energy supplies. Third, hydroelectricity is environmentally friendly. It does not emit greenhouse gases, and hydroelectric dams can be used to control floods, divert water for irrigation purposes, and improve navigation on a river. 

Approximately 10% of U.S. electrical energy is produced by hydroelectric dams.6 Although there are few economic and environmentally acceptable dam sites remaining, in some places it is possible to use wind power, or perhaps even the ocean tides, to generate electricity. Here the opportunity for chemists and chemical engineers is the invention and production of modern materials that can make such approaches possible. 

Our Future Economy May Be Based on Hydrogen Electricity-producing hydroelectric dams depend on the water cycle, which is driven by solar radiation. Windmills harness wind to produce electricity and also to pump water, and... 

There is great potential for increasing the output of hydroelectric power, but not by building more dams. Only 2400 of the 80,000 existing dams in the United States are used to generate power. Many of these untapped dams could be fitted with turbines and generators. Furthermore, most hydroelectric dams in the United States were built in the 1940s, when equipment was not... 

Why do many environmental groups oppose building more hydroelectric dams when these dams... 

Batteries are likely to find an increasing application in this role. Although electrochemical storage may prove a less cost-effective alternative in some situations, it has many advantages. Batteries have a much shorter lead time in manufacture than most competitive systems, and being modular (unlike a hydroelectric dam or compressed air store), the energy storage facility can be added to, split into smaller units, or even transported... 

Iceland s potential to generate power from hydroelectric dams is also considerable because of the country s large area of mountainous terrain, glacial melt, and reliable precipitation. Hydroelectric plants in the country currently have a capacity of approximately 1,000 mw12 and supply more than 6.8 million Mwh per year of electricity.13 In March 2003, Iceland approved plans for an Alcoa Inc. aluminum smelter and a 630 mw hydroelectric facility to provide power for this very electricity-intensive process.14 This decision has encountered opposition from environmental groups because the resulting reservoir will flood land in an undeveloped wilderness area. 

In autumn 2006, the national power company of Iceland blocked two glacial rivers near the mountain of Karahnjukar in order to flood a wilderness area of 22 square miles and create a reservoir that would supply power for a new aluminum smelting facility built by the American company, Alcoa. The hydroelectric dam, the tallest of its kind in Europe, was expected to generate 4600 GWh of electricity each year, and the smelter had the capacity to process 344,000 metric tons of aluminum annually. In addition to the 400 jobs the project was expected to provide, Alcoa also claimed that theirs would be the safest, most environment-friendly smelter on Earth. Some Icelanders contested this assertion, however, by pointing out the 45 miles of tunnels, 31 miles of high-tension power lines, and the sulfur dioxide fumes associated with... 

Someday, the new warm superconductors will be used to replace conventional conductors in anything electric or electronic—computers, transmission lines, the magnets in medical imaging devices, generators in a car, a factory, spaceship, or a hydroelectric dam. All kinds of switches and sensors, is the way Donna Fitzpatrick of the Department of Energy puts it. 

The continued construction of hydroelectric dams and expansion of agricultural and urban areas adds urgency to increasing our ability to forecast biogeochemical consequences of such developments in the Amazon basin. Applications of limnological understanding to timber management in flooded forests, to fisheries, to conservation of aquatic biodiversity, to control of waterborne disease vectors and to amelioration of... 

Petrere, M. Jr., and M. C. L. B. Ribeiro. 1994. "The impaa of a large tropical hydroelectric dam the case of Tucutui in the middle River Tocantins." Acta Limnologia Brasiliensia 5 123-133. 

Identify and describe both the positive and negative impacts of the two alternative means of power generation photovoltaic solar panels and hydroelectric dams. 

Tropical rain forests are important in maintaining the balance of CO2 and O2 in the earth s atmosphere. In recent years a portion of the South American forests (by far the world s largest) larger than France has been destroyed, either by flooding caused by hydroelectric dams or by clearing of forest land for agricultural or ranching use. 

Hydroelectric dams could also be impacted by fuel cells. With more fuel cells around, electricity prices may fall and dam owners could make more profit selling hydrogen than selling electricity. 

Tennessee Valley Authority v. Hill, 437 U.S. 153 (1978). The snail darter, which had no economic or recreational value, was found to be endangered by the Fish and Wildlife Service. The Supreme Court decided that this finding, along with the prevailing scientific view that a hydroelectric dam planned for the Little Tennessee River would destroy the... 

Castor oil-urethanes Acrylics Coatings for hydroelectric dams and iron, tough plastics Tan, 1994 Xie etal, 1993 Sperling et a/., 1981... 

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