Hydropower

Hydropower uses the water flows in a river or channel or the movement from the waves in a sea or ocean. It has been used for centuries to do mechanical work, such as milling grain, sawing timber, or extracting metal ore. Today, it is the most commonly used source of renewable energy for electricity generation. 

Hydropower accounts for 16% of all of the electricity produced in the world. Countries that have easy access to water, such as Canada, Brazil, and Norway, use hydroelectric power stations extensively. In cases in which the water flow is insufficient or unsustained, a dam can be installed to create a lake the water that flows through the spillway of the dam can be converted to electricity for the power grid. The largest hydropower plant in the world is Itaipu, located on the Parand River, across the Brazil-Paraguay border. Twenty-five percent of the electricity consumed by Brazil and 90% of that consumed by Paraguay is provided by the Itaipu hydroelectric dam, which was elected one of the seven modem Wonders of the World in 1994. 

The main cost of the power station is in the construction cost, which covers 80-90% of the total lifetime cost. The capital expenditures are high but the operational costs are low. It is estimated that the lifetime cost of a new hydroelectric power station is 0,065-0.100 per kWh, which makes it more expensive than wind but cheaper than 

CURRENT AND FUTURE STATE OF ENERGY PRODUCTION AND CONSUMPTION 

The major downsides of hydropower are the limited number of locations where hydropower plants can be built and when these locations are appropriate, the cost is huge. However, there is no intermittency and it is an excellent way to generate peak electricity. There is no CO emitted during the production of electricity but some is produced during the construction of the hydroelectric power plant. 

The water in rivers and streams can be captured and turned into hydropower (HP), also called hydroelectric power. HP currently provides about 17% of the world s electricity supply, virtually all of Norway s electricity and more than 40% of the electricity nsed in developing countries. However, there is great potential in hydropower worldwide. Norway produces more than 99% of its electricity with hydropower. New Zealand nses hydropower for 75% of its electricity. HP provides more than 97% of all electricity generated by renewable sources. Other sources, biomass, geothermal, solar and wind account for less than 3% of renewable electricity production. When the electricity share of total energy consumption is considered, the increase becomes even more dramatic. 

Hydroelectricity, at present the most important of the clean, econonucally feasible, renewable energy options, can benefit from a water resources development project however, that is seldom the only benefit. It is clear, therefore, that hydro-power has an important role to play in the future, both in terms of energy supply and water resources development. 

Dams are individually unique stractures and dam constraction represents the largest stmctures of basic infrastructure in all nations. The construction of a dam and power plant, along with the impounding of a reservoir, creates certain social and physical changes. The total installed capacity of HP is 640 000 MW (26% of the theoretical potential), generating an estimated 2380 TWh/year in the world, producing nearly 20% of the total global supply of electricity. 

Investment costs for SHP plants vary according to site-specific and local characteristics. The most important system and cost elements are (1) civil engineering, (2) equipment, and (3) turbine. The electrical generator represents less than 5% of the total cost of a power plant and the efficiency of generators for new plants is already close to 100%. However, standardization of generator equipment for small hydropower could further reduce installation and maintenance costs. 

Despite the recent debates, few would disclaim that the net environmental benefits of hydropower are far superior to fossil-based generation. Hydroelectricity is produced for an average of 0.85 US0 per kWh. In comparison with hydropower, thermal plants take less time to design, obtain approval, build and recover investment. 

The Yenisey River in Siberia passes north through the City of Krasnoyarsk. Two hydro dams on the Yenisey River each produce 6,000 MW which is primarily used in the electrolytic production of aluminum from imported bauxite ore. Such power source can also be used to make hydrogen and other electrochemical products. 

Solar ponds are presently being tested in Israel where plans are in progress for a large unit located at the Dead Sea. 

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These industries try to locate near a source of hydropower (Niagara Falls or Hoover Dam) or near a source of excess nuclear power. They generally work out arrangements to get power at a reduced cost based on being the first one cut off when electric load shedding is required. 

The widespread availabiHty of electrical energy completely transformed modem society and enabled a host of breakthroughs in manufacturing, medical science, communications, constmction, education, and transportation. Centralized fossil fuel-powered, steam-turbine-based power plants remain the dominant means of electricity production. However, hydropower faciHties such as the 1900-MW Hoover Dam Power Project located on the Arizona—Nevada border, commissioned by the U.S. Bureau of Reclamation during the 1930s, have also made significant contributions. 

In 1986, Congress passed the Electric Consumers Protection Act (ECPA), which set the foundation for more efficient relicensing of hydropower facihties, enhanced competition among apphcants for relicensing, and ensured a balance between environmental interests and the need for hydropower development. 

The extent to which each technology is poised to advance is described in separate discussions of photovoltaics, solar-thermal power, and wind, biomass, waste-to-energy, geothermal, hydropower, and wave energy. 

Because the best sites for hydropower dams have already been developed, constmction of additional large, conventional plants is unlikely. However,... 

Pneumatic systems use the wave motion to pressurize air in an oscillating water column (OWC). The pressurized air is then passed through an air turbine to generate electricity. In hydrauhc systems, wave motion is used to pressurize water or other fluids, which are subsequendy passed through a turbine or motor that drives a generator. Hydropower systems concentrate wave peaks and store the water dehvered in the waves in an elevated basin. The potential energy suppHed mns a low head hydro plant with seawater. 

The wodd s total capacity of grid-coimected electric power derived from wave energy is less than half a megawatt, distributed among several demonstration plants. The largest unit, the 350-kWe Tapered Channel plant in Norway, uses the hydropower approach. The plant was developed by Norwave AS and has operated continuously since 1986. Based on this durabiUty, two commercial orders were placed from other parts of the wodd. 

DOE Hydropower Program Biennial Report 1992—1993, DOE/ID-10424, Idaho National Engineering Laboratory, Idaho Falls, July 1993. 

The World Bank grants financing for fossil fuel electricity generation, yet finances only facilities that have advanced emission control equipment. And although the World Bank has never financed a nuclear power plant, a zero carbon emitter, it is vciy active in evaluating hydropower projects, helping to establish the World Commission on Large 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. 

This article begins with a description of how hydroelectricity works, from the beginning of the hydrological cycle to the point at which electricity is transmitted to homes and businesses. The histoiy of the dam is outlined and how dams evolved from structures used for providing a fresh water supply to irrigation and finally to providing electricity. The histoiy of hydropower is considered and the different hydroelectric. systems (i.e., conventional, run-of-... 

By the early twentieth centui y, hydroelectric power was providing more than 40 percent of electricity generation in the United States. In 1940, hydropower supplied about three-fourths of all the electricity consumed in the West and Pacific Northwest, and still supplied about one-third of the total U.S. electricity supply. Although hydroelectric-ity s share of total electricity generation has since fallen to about 10 percent in the United States, hydro-electricity provides almost one-fifth of the world s total electricity generation today. 

National Hydropower Association. (2000). Hydro Facts. . 

U.S. Department ofEnergy, Idaho National Engineering and Envirnnmeiit Labnratoi"y (2000) Hydropower Program . 

Can hydrogen be produced sustainably Over the next few decades, and probably well into the twenty-first centui y, fossil sources such as natural gas or coal may offer the lowest costs in many locations, with small contributions from electrolysis powered by low-cost hydropower. 

Reduction of overall energy use is one solution to the above problems. It requires money, technical advances, political power, and courage some reduction has been achieved, but much more is needed to reduce emissions of gases. One solution being advanced is use of processes to produce energy that do not emit gases. Hydropower has been exploited about as fully as possible, and supplies only a small fraction of total energy needs. Other sources such as wind and solar power are still much too expensive. 

Federal Energy Regulatory Commission statistics show hydropower generation at 3,700 MW (cf 1992 figure of 91,600 MW). 

The Bonneville Project Act creates the Bonneville Power Administration (BPA), which markets electricity generated at Federal hydro projects to the northwestern United States it also owns the nation s largest network of long-distance, high-voltage transmission lines needed to bring hydropower to market. 

Congress amends the Federal Power Act, increasing environmental review ot hydropower projects. 

In a thorough ecological comparison of electrochemical with other manufacturing methods, of course, the pollution of air and water by the additional generation of electric power must also be taken into account. Fortunately, the largest electrochemical industries, such as aluminum production, as a rule are concentrated around ecologically clean hydropower plants. 

Lowered Water Levels from Evaporation (possibly affecting shipping, water supply quality, hydropower production in the Great Lakes—St. Lawrence system). 

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