17-10-2016, 09:18 AM
1459278241-8hydroelecricpower.pptx (Size: 1.36 MB / Downloads: 5)
Hydroelectric power (hydropower) systems convert the kinetic energy in flowing water into electric energy.
Hydroelectric power is considered a renewable energy source. A renewable energy source is one that is not depleted (used up) in the production of energy. Through hydropower, the energy in falling water is converted into electricity without “using up” the water.
Hydropower energy is ultimately derived from the sun, which drives the water cycle. In the water cycle, rivers are recharged in a continuous cycle. Because of the force of gravity, water flows from high points to low points. There is kinetic energy embodied in the flow of water.
Humans first learned to harness the kinetic energy in water by using waterwheels.A waterwheel is a revolving wheel fitted with blades, buckets, or vanes.Waterwheels convert the kinetic energy of flowing water to mechanical energy.
After the discovery of electricity, it was realized that a turbine’s mechanical energy could be used to activate a generator and produce electricity.
The first hydroelectric power plant was constructed in 1882 in Appleton, Wisconsin. It produced 12.5 kilowatts of electricity which was used to light two paper mills and one home.
Flow rate and head
The amount of electricity produced depends upon
the amount of water flowing (flow rate) and the
height from which water falls (head).
There are high-head and low-head hydropower systems.
Low-head hydropower systems are generally less than 20 feet high.
The two primary types of hydropower facilities are the impoundment system (or dam) and the run-of-the-river system.
calculation
A standard equation for calculating energy production:
Power = (Head) x (Flow) x (Efficiency) /11.8
Power = the electric power in kilowatts or kW
Head = the distance the water falls (measured in feet)
Flow = the amount of water flowing (measured in cubic feet per second or cfs)
Efficiency = How well the turbine and generator convert the power of falling water into electric power. This can range from 60% (0.60) for older, poorly maintained hydroplants to 90% (0.90) for newer, well maintained plants.
11.8 = Index that converts units of feet and seconds into kilowatts