Hydro electric power generation


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Hydro electric power generation

  1. 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. 2. • The dam’s, 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. 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. 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. 5.  Pumped storage plant  Run-of-river projects  Impoundment
  6. 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. 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. 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. 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. 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. 11. 2. Generators
  12. 12. * No pollution * Renewable energy source * Very reliable energy source * Not expensive to maintain * Can increase or decrease the plant’s production whenever there is high or low demand respectively * Water can be stored, waiting to be used in peak times
  13. 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. 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.