Classification of Hydroelectric Power Plants
More on Power Generation
Hydro Electric Power plants
Classification of Hydroelectric Power Plants
Gas Power Plants
Wind Power Generation
Nuclear Power Generation
Diesel power plants
Hydro energy is one of the renewable forms of energy. Hydro electric power plants have very high efficiency when compare to any other power plant. They have very long life, lesser impact over the environment, low production cost, lesser maintenance and flexibility in operation and control. The main drawbacks of these power plants are higher cost during construction and the land requirement for construction of reservoir.
Hydro electric power plants can be classified based on their location, the presence and absence of storage, range of operation, operational features etc.
Layout of Hydro electric power plants
Conventional hydroelectric plant
Pumped storage hydroelectric plant
Tidal power plant
Classification based on the hydraulic features
Based on the hydraulic features hydro electric power plants can be classified into the four types:
conventional hydro electric plants:
These plants utilize the hydraulic energy of the flowing water of the rivers. Dams are constructed to collect the water in the reservoir and is used to run the turbines.
Pumped storage plants
In this type of hydroelectric power plants the same water is utilized again and again by pumping back during the off peak hours. They are mainly used to meet the peak demand.
Tidal power plant
These power plant produces electric energy from the tides of the seas.
Depression power plants:
In this type of power plant water is diverted into a natural topological depression which provides head for the plant. Water is diverted from ample resources such as seas. It is a rare type of power plant. This type of power plants exists in Egypt.
Classification based on the operation
Base load plants
This type of plants involves in continuous power generation. Simply speaking conventional hydroelectric power plants are base load plants.
Peak load plants
If the power plant is operated only to meet the peak demand then it is called peak load plants. In general, pumped storage power plants are peak load plants. In this type of hydroelectric power plants the same water is utilized again and again by pumping back during the off peak hours.
Classification based on storage
By considering the availability of storage reservoirs, hydro electric power plants can be classified into power plants having storage reservoir and without storage reservoir. If the availability of the water is uneven over the year, storage reservoirs are essential. If there is a natural normal flow throughout they year then it is not essential to have a reservoir. Under such conditions a mini reservoir or pond that takes care of day to day fluctuations is enough.
Classification based on plant capacity
| Type | capacity |
|---|---|
Very low capacity hydro electric plants | Up to 0.1 MW |
Low capacity hydro electric plants | Up to 1.0 MW |
Medium capacity hydro electric plants | Up to 10 MW |
High capacity hydro electric plants | More than 10 MW |
They can also be classified as follows
| Type | Capacity |
|---|---|
Micro hydro electric plants | < 100 kW |
Mini hydro electric plants | 100kW to 1MW |
Small hydro electric plants | 1 MW to a few MW |
Medium hydro electric plants | More than a few MW |
Super hydro electric plants | More than 1000 MW |
Classification based on head
Based on the available head hydro power plants are classified into the following:
| Type | Head |
|---|---|
Low head plants | < 15 m |
Medium head plants | 15 – 70 m |
High head plants | 70 – 250 m |
Very high head plants | More than 250 m |
High head power plants
High head plants
Due to high head, small amount of water can produce large amount of power. Therefore these types of plants are very economical. The reservoir is found at the top of the mountain and the power house is found at the foot. For high head plants catchment area of small capacity is sufficient. If the water from one stream is not sufficient, more than water can be diverted from the neighboring streams. For heads above 500 m, Pelton turbine is used and for low heads Francis turbines are used.
Medium head plants
Larger volume of water is required in this type if power plant. The reservoir capacity will be large. In these power plant water is carried from the reservoir is carried to the penstock through the forebay. There is no need of surge tank as forebay itself acts as a surge tank. Francis, Kaplan and Propeller turbines are commonly used for the medium head plants.
Low head plants.
Low head plants require larger volume of water than high and medium head plants to produce same amount of power. The reservoir capacity will be large. Francis, Kaplan and Propeller turbines are commonly used for the low head plants.
Comments
LUZ CANAS from CALOOCAN CITY on July 06, 2019:
thank you for your explanation. now i understand it.
Abhishek S on May 31, 2017:
Nice explainations
Biki on April 18, 2016:
Thanks ...sir
kamlesh yadav on February 20, 2015:
good
OSBERT JOEL C (author) from CHENNAI on March 31, 2014:
You are welcome
gat on March 31, 2014:
Thank you
OSBERT JOEL C (author) from CHENNAI on January 16, 2014:
Thank you lesliebyars..
lesliebyars on January 16, 2014:
You explained things that I never knew about power plants. I used to live near a power plant. When we would go, to look at the water, we felt so small next to it's massiveness in size. It was amazing to think of the technology that is involved. I voted up, useful and interesting. Thank you for sharing.
OSBERT JOEL C (author) from CHENNAI on January 15, 2014:
Thank you both of you!
Adityapullagurla on January 15, 2014:
How amazing are these types of power plants .. really good hub
CJ Kelly from the PNW on January 15, 2014:
You really have a gift for explaining these technologies. Very interesting.
