Hydroelectricity is one of the main forms of energy in use today. Its use is being promoted in many countries of the world as a renewable and non-polluting source of energy. The industrialized nations of the world have drawn flak in recent times for releasing high concentrations of green house gases into the atmosphere. The regulations of the Kyoto Protocol are making things tougher. Hence greater interest is being shown in making use of non-polluting energy sources.
Functioning of a hydroelectric power plant
Hydroelectricity is produced in a hydroelectric power plant. In this plant, the water is released from a high location. The potential energy present in the water is converted into kinetic energy, which is then used to rotate the blades of a turbine. The turbine is hooked to the generator which produces electricity.
The main components of hydroelectric power plant are:
a) The reservoir: Water from a natural water body like a river is stored in the reservoir. This reservoir is built at a level higher than the turbine.
b) The dam: The flow of water stored in the reservoir is obstructed by huge walls of the dam. This prevents the water from flowing and helps us harness the energy present in it. The dam consists of gates present at its bottom, which can be lifted to allow the flow of water through them.
c) The penstock: This connects the reservoir with the turbine propeller and runs in a downward inclined manner. When the gates of the dam are lifted, the force of gravity makes the water flow down the penstock and reach the blades of the turbine. As the water flows through the penstock, the potential energy of water stored in the dam is converted into kinetic energy.
d) The turbine: The kinetic energy of the running water turns the blades of the turbine. The turbine can be either a Pelton Wheel Model or a Centrifugal type. The turbine has a shaft connected to the generator.
e) The generator: A shaft runs from the turbine to the generator. When the blades of the turbine rotate, the shaft turns a motor which produces electric current in the generator.
f) Power lines: The power produced in the generator is sent to various power distribution stations through the power lines.
After passing through the turbine, the water flows through an outlet pipe called the tailrace and is released into the river downstream of the power plant.
