hydro electric power generation
Post on 11-May-2015
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- 1. This is the generation of power by harnessing the energy of flowing water. This presentation will focus on; * Factors considered when selecting the generation site * Types of hydro-electric power plants * How power is generated using this method * Advantages and Disadvantages of this method
2. The dams, bed and walls must sustain the hydraulic pressures of water hence the following should be considered; *Good topographical location along the river (wide and flat valley) *Right geological structure (strong & stable rock structure) *Availability of sufficient water (flow of the river should accommodate for evaporation in the dam) 3. Before development of a station the expected power is computed as follows; The measure of mechanical energy=THP THP= (Q * H) /8.8 Q=flow rate[m3/s] , H= head[m] , 8.8=constant Expected power is given by conversion 1THP= 746W 4. These power stations have different capacities of power varying from each size; * Large Hydropower (more than 30MW) * Small Hydropower (100 kW to 30 MW) * Micro Hydropower (up to 100 kW) 5. Pumped storage plant Run-of-river projects Impoundment 6. It is a method of keeping water in reserve for peak period power demands by pumping water that has flowed through the turbines back up a storage pool at a time when customer demand for energy is low i.e. (during the middle of the night). 7. * A run-of-water-project(diversion), facility channels a portion of a river through a canal or penstock. * It may not require the use of a dam. An example of diversion hydro-power plant in Alaska 8. This is most common type of hydroelectric power plant. It is a large hydropower system, that uses a dam to store river water in a reservoir. 9. The dam stores water behind it in the reservoir. Gravity causes the water to fall through the intake into the penstock inside the dam. The moving water turns the turbine propeller at the end of the penstock. The turbine shaft spins the generator. As the generator rotor spins the magnets, a flow of electrons is created in the coils of the stator. The produced electricity is stepped up and transmitted to consumers. The water continues past the propeller into the river. 10. The key tech element involved in the energy conversion process is mechanical-to-electrical. The major components are; 1.Turbines (a) impulse turbine:-applicable were high head of water is available. (b) reaction turbine:-used for head below 450m 11. 2. Generators 12. * No pollution * Renewable energy source * Very reliable energy source * Not expensive to maintain * Can increase or decrease the plants production whenever there is high or low demand respectively * Water can be stored, waiting to be used in peak times 13. * Building the dam is expensive and time taking * Silt deposits can shorten the operational lifespan of hydroelectric reservoirs * Relocation of the people living were the dam is to be built 14. Hydro-electric power is an important part of the world's electricity supply, providing reliable, cost effective electricity, and is expected to continue to do so in the future. Hydro power has less negative environmental impacts which are very different from those of fossil fuel power plants.