Hydro power plant

HYDROPOWER PLANT

Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy, accounting for 16 percent of global electricity consumption, and 3,427 terawatt-hours of electricity production in 2010, which continues the rapid rate of increase experienced between 2003 and 2009.[1]

 Hydropower is produced in 150 countries, with the Asia-Pacific region generating 32 percent of global hydropower in 2010. China is the largest hydroelectricity producer, with 721 terawatt-hours of production in 2010, representing around 17 percent of domestic electricity use. There are now three hydroelectricity plants larger than 10 GW: the Three Gorges Dam in China, Itaipu Dam in Brazil, and Guri Dam in Venezuela

The cost of hydroelectricity is relatively low, making it a competitive source of renewable electricity. The average cost of electricity from a hydro plant larger than 10 megawatts is 3 to 5 U.S. cents per kilowatt-hour.[1] Hydro is also a flexible source of electricity since plants can be ramped up and down very quickly to adapt to changing energy demands. However, damming interrupts the flow of rivers and can harm local ecosystems, and building large dams and reservoirs often involves displacing people and wildlife.[1] Once a hydroelectric complex is constructed, the project produces no direct waste, and has a considerably lower output level of the greenhouse gas carbon dioxide (CO2) than fossil fuel powered energy plants.[2]

Hydropower plant

Hydropower has been used since ancient times to grind flour and perform other tasks. In the mid-1770s, French engineer Bernard Forest de Bélidor published Architecture Hydraulique which described vertical- and horizontal-axis hydraulic machines. By the late 19th century, the electrical generator was developed and could now be coupled with hydraulics.[3] The growing demand for the Industrial Revolution would drive development as well.[4] In 1878 the world's first hydroelectric power scheme was developed at Cragside in Northumberland, England by William George Armstrong. It was used to power a single arc lamp in his art gallery.[5] The old Schoelkopf Power Station No. 1 near Niagara Falls in the U.S. side began to produce electricity in 1881. The first Edison hydroelectric power plant, the Vulcan Street Plant, began operating September 30, 1882, in Appleton, Wisconsin, with an output of about 12.5 kilowatts.[6] By 1886 there were 45 hydroelectric power plants in the U.S. and Canada. By 1889 there were 200 in the U.S. alone.[3]

History of hydropower plant

Hydropower or water power is power derived from the energy of falling water, which may be harnessed for useful purposes. Since ancient times, hydropower has been used for irrigation and the operation of various mechanical devices, such as watermills, sawmills, textile mills, dock cranes, and domestic lifts.Since the early 20th century, the term is used almost exclusively in conjunction with the modern development of hydro-electric power, which allowed use of distant energy sources. Another method used to transmit energy used a trompe, which produces compressed air from falling water. Compressed air could then be piped to power other machinery at a distance from the waterfall.Water's power is manifested in hydrology, by the forces of water on the riverbed and banks of a river. When a river is in flood, it is at its most powerful, and moves the greatest amount of sediment. This higher force results in the removal of sediment and other material from the riverbed and banks of the river, locally causing erosion, transport and, with lower flow, sedimentation downstream.

Conventional (dams)Most hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. The power extracted from the water depends on the volume and on the difference in height between the source and the water's outflow. This height difference is called the head. The amount of potential energy in water is proportional to the head. A large pipe (the "penstock") delivers water to the turbine.Pumped-storageMain article: Pumped-storage hydroelectricityThis method produces electricity to supply high peak demands by moving water between reservoirs at different elevations. At times of low electrical demand, excess generation capacity is used to pump water into the higher reservoir. When there is higher demand, water is released back into the lower reservoir through a turbine. Pumped-storage schemes currently provide the most commercially important means of large-scale grid energy storage and improve the daily capacity factor of the generation system

Generating methods

.Run-of-the-riverRun-of-the-river hydroelectric stations are those with small or no reservoir capacity, so that the water coming from upstream must be used for generation at that moment, or must be allowed to bypass the dam.TideA tidal power plant makes use of the daily rise and fall of ocean water due to tides; such sources are highly predictable, and if conditions permit construction of reservoirs, can also be dispatchable to generate power during high demand periods. Less common types of hydro schemes use water's kinetic energy or undammed sources such as undershotwaterwheels.UndergroundAn underground power station makes use of a large natural height difference between two waterways, such as a waterfall or mountain lake. An underground tunnel is constructed to take water from the high reservoir to the generating hall built in an underground cavern near the lowest point of the water tunnel and a horizontal tailrace taking water away to the lower outlet waterway

Hydropower types

Hydropower is used primarily to generate electricity. Broad categories include: A conventional dammed-hydro facility (hydroelectric dam) is the most common type of hydroelectric power generation.•Conventional hydroelectric, referring to hydroelectric dams.•Run-of-the-river hydroelectricity, which captures the kinetic energy in rivers or streams, without the use of dams.•Small hydro projects are 10 megawatts or less and often have no artificial reservoirs.•Micro hydro projects provide a few kilowatts to a few hundred kilowatts to isolated homes, villages, or small industries.•Pumped-storage hydroelectricity stores water pumped during periods of low demand to be released for generation when demand is high.

Used as a source of generating power for hundreds of years, Hydropower is the harnessing of the force of moving water and producing energy to be used in multiple applications.Dating back to ancient times, hydropower was used for the operation of various machines, such as watermills, sawmills, dock cranes and also for irrigation purposes. Back in Roman times, water was the source of energy that powered mills to extract flour from grains and to cut timber and stone in the construction of the city and its dwellings.

Along with the impact on ecosystems, a lesser-known result from the construction of hydroelectric plants is the dispersing of the local population. It is not often thought about, but it has been estimated that between 40 and 80 million people worldwide have been relocated due to the construction of dams and other hydropower plants.

The first known hydropower plant built in the U.S. occurred in 1880, in Grand Rapids, Michigan. The so-called “boom” in larger scale plants did not take place until the 1930s and into the 1940s as part of President Roosevelt's "New Deal" program.In the modern world, the use of hydropower is the catalyst in producing hydroelectricity. In its practice, hydroelectricity allows an end user the use of the energy produced by the water source in a lower, more cost effective manner.Hydroelectricity is produced from hydropower, which is the generation of energy through the use of gravitational forces from flowing or falling water, usually from dams or rivers. Throughout the world, hydroelectric power supplies nearly 19% of electricity, or 715,000 MWe (megawatt electrical). It also represents more than 63% of the electricity used from renewable sources

.The greatest benefit from the use of hydropower is that it produces no carbon dioxide emissions or other harmful discharges, such as sulfur dioxide, carbon monoxide, and nitric acid, unlike the use of fossil fuels. Hydropower also generates no waste by-products and has no affect on today’s growing concerns with global warming.One of the most widely used devises for the production of hydropower is the dam. Currently there are more than 75,000 dams in the U.S. blocking more than 600,000 miles of our nation’s rivers, or 17% of the free flowing water.

Within the United States, the Grand Coulee Dam, on the Columbia River in Washington State, currently holds the title as the country’s largest electric power producing facility, and is the fifth largest producer in the world. The dam also holds the distinction of being the largest concrete structure in North America as well, surpassing the Hoover Dam when constructed in 1942.

With the use of dammed water, the potential energy source is used to drive water turbines and generators. The key element to the production of hydropower is dependent on the volume of the water, and the height difference between the original source of the water, the dammed water, and the position of the outflow. This difference in the height is paramount to produce the optimal amount of energy from the flowing water.

Rounding out the top five dams in the world, the Grand Coulee is surpassed by only the Three Gorges Dam in China, the Guri Dam in Venezuela, the Itaipu Dam on the border of Paraguay and Brazil, and the Sayano-Shushenskaya Dam in Russia.In addition to the more common practices of waterpower, several other forms are in use or in developmental stages as well. Included are damless hydropower, which harnesses the kinetic energy of rivers, streams and oceans, and wave power, which captures the energy produced by waves.

One of the up-and-coming developments is from the use of tidal stream power. Still in its infancy, this technology draws energy from the currents of high volume river and streams. Requiring much more research, early models have shown some promise.Despite the numerous advantages that hydropower possesses, there certainly are concerns that are raised by the construction and usage of hydroelectric plants. The most common, negative perception of these plants is the affects surrounding environmental damage, namely the disruption of the local ecosystems.

Hydropower's effect on the environmentHydropower is a clean source of energy. There are no problems with air pollution, chemical runoff, toxic waste or the like.Hydropower plants also create recreation areas and animal habitat. Because of the change in water location, wide areas after the dam become great for water edge species of animals.  And the large reservoir is good for many types of large fish. Boating areas are created in the reservoir too, as well as bird watching sites downstream of the dam.Some problems may still occur though., but through careful planning these can be eliminated almost completely.

Temporary disruption in the ecology to build the dam, but afterwards this cleared land can be used to make animal habitat.downstream of the dam, water flow may be significantly reduced, but careful monitoring of the land downstream of the dam can give operators enough information to allow more water to pass through the dam.Catadramous fish (fish that live in salt water and spawn in fresh water) migration may be interupted- but fish ladders and fish elevators may be installed to eliminate this problem. Anadromous (fish that live in fresh water and spawn in salt water) fish do not have this problem, because they can go right through the turbines which only spin at 81.8 rpms.Flooding of land upstream of the dam can be a problem, but careful monitoring of the land upstream of the dam can give operators enough information to allow more water to run through the dam to compensate for this problem.

Advantages of hydropowerIt is a clean and safe source of energyThey are self sustainingThey create habitat for more types of fishThey can act as a flood controllerThey are the most efficient energy source running from 90-95% efficiencyOther forms of HydropowerTidal power: electricity generated by turbines moved by the tides. This is still in experimental stages.Ocean thermal power: power generated by the thermal expansion of the ocean. This can only be used in a location like the Gulf stream.Geothermal power: natural steam is used underground to turn turbines. This is limited to location which have these phenomenon.