Hydro electric power generationPresentation Transcript
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
• 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
*Availability of sufficient water (flow of the
river should accommodate for evaporation in the
• 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
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)
• 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).
* 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
• 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.
• 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
The key tech element involved in the energy
conversion process is mechanical-to-electrical.
The major components are;
(a) impulse turbine:-applicable were high head of
water is available.
(b) reaction turbine:-used for head below 450m
* 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
* Water can be stored, waiting to be used in peak
* 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
• 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.