HYDRO ELECTRIC POWER PLANT

Introduction:Energy is the most important thing in this world. All living plants, animals (organisms) on this earth require energy to perform any type of work. The capacity to do a work is energy. The energy may require in smaller amount or in larger amount depending upon the nature of work to be performed.The different things from which we get the energy are called as Energy Sources. This is the simplest meaning of energy sources. There are two types of energy sources:1. Conventional OR Non-Renewable Energy Sources2. Non-Conventional OR Renewable Energy Sources

1. Conventional OR Non-Renewable Energy Sources:The energy sources, which we are using from long time and which are in danger of exhausting, are called as Conventional OR Non-Renewable Energy Sources. They are not renewed by Nature and they are perishable, are going to get exhausted one day. e. g. coal, petroleum products, nuclear fuels etc.2. Non-Conventional OR Renewable Energy Sources:These are the energy sources whose utilization technology is not yet fully developed. These are the sources, which can be recovered and reused. i. e. they can be used again and again to generate energy because of the renewal of their energyWe are going to consider one of the ways of generation of energy from non-conventional energy namely hydroelectric energy. As name suggest, it is the energy obtained from water.The main principle used in this type is the kinetic energy of falling water is converted into electric energy using turbines.

History of hydro power developmentThe first recorded use of water power was a clock, built around 250 BC. Since that time, humans have used falling water to provide power for grain and saw mills, as well as a host of other applications. The first use of moving water to produce electricity was a waterwheel on the Fox River in Wisconsin in 1882, two years after Thomas Edison unveiled the incandescent light bulb. The first of many hydro electric power plants at Niagara Falls was completed shortly thereafter. Hydro power continued to play a major role in the expansion of electrical service early in this century, both in North America and around the world. Contemporary Hydro-electric power plants generate anywhere from a few kW, enough for a single residence, to thousands of MW, power enough to supply a large city. Early hydro-electric power plants were much more reliable and efficient than the fossil fuel fired plants of the day. This resulted in a proliferation of small to medium sized hydro-electric generating stations distributed wherever there was an adequate supply of moving water and a need for electricity. As electricity demand soared in the middle years of this century, and the efficiency of coal and oil fueled power plants increased, small hydro plants fell out of favor. Most new hydro-electric development was focused on huge "mega-projects". The majority of these power plants involved large dams which flooded vast areas of land to provide water storage and therefore a constant supply of electricity. In Recent years, the environmental impacts of such large hydro projects are being identified as a cause for concern. It is becoming increasingly difficult for developers to build new dams because of opposition from environmentalists and people living on the land to be flooded. This is shown by the opposition to projects such as Great Whale (James Bay II) in Quebec and the Gabickovo-Nagymaros project on the Danube River in Czechoslovakia. Hydropower generation is an improvarient of primitive water wheel for grinding cereals. As hydro-electric power it emerged in USA in1882, followed by sweeden and Japan. In India, hydropower plant OF 130kw installed capacity was commissioned in 1897 at sidrapong at Dargiling in West Bengal and followed by 4.5MW plant at sivsamudram in Karnataka in 1902.during period between two world wars, a number of hydro power plants such as 48MW, at Jogindernagar(H.P.),17.4MW ganga power plant(U.P.), 38.75MWpykaraand 30MWmatter(Chnnai)were commissioned,from installed capacity of 1362MW,out of which hydropower was 508 MW in 1947,the pace of growth has been rapid in post independence era. The hydal install capacity by the end 2001 is 25,574MW, out of total capacity of 102907MW.

Hydroelectric power Electricity produced from generators driven by water turbines that convert the energy in falling or fast-flowing

water to mechanical energy. Water at a higher elevation flows downward through large pipes or tunnels (penstocks). The falling water rotates turbines, which drive the generators, which convert the turbines' mechanical energy into electricity. The advantages of hydroelectric power over such other sources as fossil fuels and nuclear fission are that it is continually renewable and produces no pollution. Norway, Sweden, Canada, and Switzerland rely heavily on hydroelectricity because they have industrialized areas close to mountainous regions with heavy rainfall. The U.S., Russia, China, India, and Brazil get a much smaller proportion of their electric power from hydroelectric generation. See also tidal power.Water is needed to run a hydroelectric generating unit. It’s held in a reservoir or lake behind the dam and the force of the water being released from the reservoir through the dam spins the blades of a turbine. The turbine is connected to the generator that produces electricity. After passing through the turbine, the water reenters the river on the downstream side of the dam. The capability to produce and deliver electricity for widespread consumption was one of the most important factors in the surge of American economic influence and wealth in the late nineteenth and early twentieth centuries. Hydroelectric power, among the first and simplest of the technologies that generated electricity, was initially developed using low dams of rock, timber, or granite block construction to collect water from rainfall and surface runoff into a reservoir. The water was funneled into a pipe (or pen-stock) and directed to a waterwheel (or turbine) where the force of the falling water on the turbine blades rotated the turbine and its main shaft. This shaft was connected to a generator, and the rotating generator produced electricity. One gallon (about 3.8 liters) of water falling 100 feet (about 30 meters) each second produced slightly more than 1,000 watts (or one kilowatt) of electricity, enough to power ten 100-watt light bulbs or a typical hairdryer.There are now three types of hydroelectric installations: storage, run-of-river, and pumped-storage facilities. Storage facilities use a dam to capture water in a reservoir. This stored water is released from the reservoir through turbines at the rate required to meet changing electricity needs or other needs such as flood control, fish passage, irrigation, navigation, and recreation. Run-of-river facilities use only the natural flow of the river to operate the turbine. If the conditions are right, this type of project can be constructed without a dam or with a low diversion structure to direct water from the stream channel into a penstock. Pumped-storage facilities, an innovation of the 1950s, have specially designed turbines. These turbines have the ability to generate electricity the conventional way when water is delivered through penstocks to the turbines from a reservoir. They can also be reversed and used as pumps to lift water from the powerhouse back up into the reservoir where the water is stored for later use. During the daytime when electricity demand suddenly increases, the gates of the pumped-storage facility are opened and stored water is released from the reservoir to generate and quickly deliver electricity to meet the demand. At night when electricity demand is lowest and there is excess electricity available from coal or nuclear electricity generating facilities the turbines are reversed and pump water back into the reservoir. Operating in this manner, a pumped-storage facility improves the operating efficiency of all power plants within an electric system. Hydroelectric developments provide unique benefits not available with other electricity generating technologies. They do not contribute to air pollution, acid rain, or ozone depletion, and do not produce toxic wastes. As a part of normal operations many hydroelectric facilities also provide flood control, water supply for drinking and irrigation, and recreational opportunities such as fishing, swimming, water-skiing, picnicking, camping, rafting, boating, and sightseeing.

Different classifications of Hydroelectric power plants: 1) Depending upon Capacity to generate power:

Size unit size InstallationMicro upto 100 kW 100 kW

Mini 101 to 1000 kW 2000 kW

Small 1001 to 6000 kW 15000 kW