Admin
Admin
عدد المساهمات : 656
تاريخ التسجيل : 14/03/2013
 |  موضوع: Hydropower issue الثلاثاء يونيو 18, 2013 11:33 am | |
|
Moving water is a powerful entity responsible for lighting entire cities, even countries. Thousands of years ago the Greeks used water wheels, which picked up water in buckets around a wheel. The water's weight caused the wheel to turn, converting kinetic energy into mechanical energy for grinding grain and pumping water. In the 1800s the water wheel was often used to power machines such as timber-cutting saws in European and American factories. More importantly, people realized that the force of water falling from a height would turn a turbine connected to a generator to produce electricity. Niagara Falls , a natural waterfall, powered the first hydroelectric plant in 1879. Man-made waterfalls dams were constructed throughout the 1900s in order to maximize this source of energy. Aside from a plant for electricity production, a hydropower facility consists of a water reservoir enclosed by a dam whose gates can open or close depending on how much water is needed to produce a particular amount of electricity. Once electricity is produced it is transported along huge transmission lines to an electric utility company. "By the 1940s, the best sites for large dams had been developed." But like most other renewable sources of energy, hydropower could not compete with inexpensive fossil fuels at the time. "It wasn't until the price of oil skyrocketed in the 1970s that people became interested in hydropower again." Today one-fifth of global electricity is generated by falling water. "Over the past 100 years, the United States has led the world in dam building. Secretary of the Interior Bruce Babbitt recently observed that, 'on average, we have constructed one dam every day since the signing of the Declaration of Independence.'"Of the 75,187 dams in the US , less than 3% are used to produce 10-12% of the nation's electricity. With over 2,000 facilities, the US is the second largest producer of hydropower worldwide, behind Canada . The dams that do not produce electricity are used for irrigation or flood control. Many people believe these pre-existing sites could contribute to the country's power supply in a cost-effective manner if hydroelectric facilities were constructed. | |
|
Admin
Admin
عدد المساهمات : 656
تاريخ التسجيل : 14/03/2013
| |
Mohammed 1
عدد المساهمات : 220
تاريخ التسجيل : 23/06/2013
| | موضوع: رد: Hydropower issue الخميس يونيو 27, 2013 10:09 pm | |
| Thank you for information bro | |
|
Admin
Admin
عدد المساهمات : 656
تاريخ التسجيل : 14/03/2013
| | موضوع: رد: Hydropower issue الجمعة يونيو 28, 2013 12:16 pm | |
| | |
|
