Q. How is power generated?
A. If a magnet is inserted into a coil of conducting wire an instantaneous current occurs in the wire which will produce a voltage which can be observed with a voltmeter, when the magnet is removed from the coil another instantaneous but opposing voltage can be observed. This effect, whereby the relative motion of a magnet and an electric coil produce a current, is known as electromagnetic induction.

In a Hydro power plant, the motion of water is used to move big fan like blades in a turbine to then turn a shaft connected to a generator. The generator has a powerful electromagnet (a rotor) which is turned inside a coil of copper bars (a stator). This produces electromotive force, or the process of exciting electrons to jump from atom to atom. When electrons flow along a wire or other conductor, jumping from atom to atom, they create an electric current, or a flow of electricity. Generators can not store the energy they create, therefore once the mechanical energy from the flow of water is converted into electricity, it must be fed to the grids.

Q. What is the meaning of Mega Watt (MW) and how is it different from units of energy?
A. Capacity of a generating unit is expressed in MW. One MW is equal to 1000 KW. Unit of energy is Kilowatt Hour i.e. a machine of 1MW capacity running for one hour would generate 1000 KWH or 1000 units.
Q. What is the difference between a ‘DAM' and a ‘BARRAGE’?
A. Both the dam and barrage are barriers constructed across a river or natural water course for storing or diverting water into a canal mainly for purposes of irrigation, water supply etc. or into a channel or a tunnel for generation of power.

In case of a DAM, its entire length across the river i.e. between the banks is provided with gates having their bottom sill near the river bed level. The DAM is constructed to completely block the river/stream and creating storage and use as per requirement.

The BARRAGE on the other hand is not primarily meant for storage of water but for diversion of water as per requirement.In both the cases, however, the number and size of gates is adequate to pass the design flood during monsoons.

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Q. What are the advantages of run of the river projects?
- Storage behind the dam or barrage is just sufficient to run the power station to its full installed capacity only for about 4-5 hours during the period the discharge in the river is minimum.
- During monsoons, the power house runs as a peaking station for the period the river discharge is more than the design discharge required for running the power house to its full installed capacity.
- Due to small storage, the height of the barrage / diversion dam is low, resulting into a smaller reservoir and consequently rehabilitation and resettlement problems are minimal.
- Forest / Government land coming under submergence is reduced to a great extent due to a small reservoir.
Q. What are the advantages of Hydro Power?
- Hydropower is a renewable source of energy as it is generated by a combination of the unending rain cycle and the abrupt topography of the earth.
- It is non-polluting and hence environment friendly.
- Hydroelectric power projects have a very long operational life. The first hydro-project completed in 1898 in India is still in operation.
- Cost of generation, operation and maintenance is lower than the other sources of energy.
- The ability of Hydropower Projects to start and stop quickly makes them suitable to meet peak demand and for enhancing system reliability and stability.
- Hydroelectric power plants offer better efficiency as compared to coal / fuel based power plants.
- Cost of generation is free from inflationary effects after the initial installation.
- Multi purpose hydro schemes often provide additional benefits of irrigation, flood control, drinking water supply, navigation, recreation, tourism, flora & fauna, etc.
- Being located in remote areas, Hydropower projects lead to betterment in terms of infrastructure and socio-economic development of those particular and adjoining areas.
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Q. What are the disadvantages of Hydro Power?
- High initial cost of facilities
- Dependence on precipitation (no control over amount of water available)
- Changes in stream regimens (can affect fish, plants, wildlife by changing stream levels, flow patterns and temperature)
- Inundation of land and wildlife habitat (creation of reservoir)
- Displacement of people
Q. What is the comparative cost of hydropower v/s other means of power generation?
A. Hydro electric production costs run about one third of those of either fossil fueled (coal or oil) or nuclear power plants, and is less than one fourth the cost of gas turbine electric production.
Q. What is the difference between a snow fed vs. a monsoon fed project?
A. Snow fed project – The run-off is derived from the melting of snow & glaciers.
Monsoon fed project – The run-off is derived from rainfall.
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Q. What is HRT – Head Race Tunnel?
A. The water from reservoir enters through the Intake into the Head Race Tunnel or Power Tunnel, which runs under pressure supplying water for generation of power to the power station. The HRT basically is a water conducting system.
Q. What is merchant power plant (MPP)?
A. Merchant Power Plant (MPP) generates electricity to sell in the open market.
Malana Power in Kullu district of Himachal Pradesh is the first MPP in India and also the first to sell power through interstate transmission of electricity.
Q. How much power ADHPL will generate for its project?
A. From the design discharge of 25 cumecs and head of 857m, ADHPL will generate 192 MW
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