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APPLICATION: Hydropower-Electricity Generation

DESCRIPTION:  There are many types of turbines used for hydropower, and they are chosen based on their particular application and the height of standing water referred to as “head” available to drive them. The turning part of the turbine is called the runner. The most common types of turbines are as follows:

?    Pelton Turbine: This turbine has one or more jets of water impinging on the buckets of a runner that looks like a water wheel. The Pelton turbines are used for high-head sites (50 feet to 6,000 feet) and can be as large as 200 megawatts.
?    Francis Turbine: This type has a runner with fixed vanes, usually none or more. The water enters the turbine in a radial direction with respect to the shaft, and is discharged in an axial direction. Francis turbines will operate from 10 feet to 2,000 feet of head and can be as large as 800 megawatts.
?    Propeller Turbine: Here there is a runner with three to six fixed blades, like a boat propeller. The water passes through the runner and drives the blades. Propeller turbines can operate from 10 feet to 300 feet of head and can be as large as 100 megawatts. A Kaplan turbine is a type of propeller turbine in which the pitch of the blades can be changed to improve performance. Kaplan turbines can be as large as 400 megawatts.

Small hydro power stations are comprised of turbine generators and the structures necessary to channel and regulate the flow of water to the turbines. Water flows from high points to low points because of the force of gravity. There is energy embodied in the flow of water, and hydroelectric power systems capture some of the energy and convert it to the electric power.

If a dam is constructed to block the flow of water, a river or stream may be channeled through turbines connected to electric generators to produce power. The power produced by the hydroelectric system is the product of three parameters: the distance the water falls from the intake to the outlet, the volume of the flow of water, and the efficiency of the turbine/generator equipment.

Components of a Small Hydro System include a Feeder Canal, a Forebay, a Penstock, a Power House, Tail Race, and an Intak. Water under pressure from a penstock or forebay drives a hydraulic turbine. The energy in the flowing water is converted to mechanical energy by a revolving wheel fitted with blades, buckets, or vanes. The flow is directed at the wheel by a nozzle or an injector allowing the flow to be adapted to the mechanical power required by the electrical equipment being driven. Generators convert the mechanical energy produced by the turbine into electrical energy. Different types of generators are used depending on the characteristics of the electrical grid the hydroelectric system is connected to.

Electric generators are more efficient when they run at high speeds. If a turbine rotates at a low speed, “step up” gearing can be installed between the turbine and the power generator to increase the rotation speed.





i.    Article(s):
A: Directory of Energy Technology
ii.    Publication(s):
iii.    Internet site (s):
?    The Australia Renewable Website (Austria Greenhouse Office)


i.    Capital or initial costs:
ii.    Operation and maintenance cost:
iii.    Fuel energy costs:





Category/ies:Hydropower Tech.
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