Advantages and Disadvantages of Hydroelectric power - Facts

What is hydroelectric power (facts) ? 

Let’s start with the hydroelectric power definition:

In hydroelectric power plants, the potential energy of water is converted into mechanical energy which runs a generator.

• Hydraulic power is a naturally available renewable energy source. 

• Power of a hydroelectric power station is given as: P = gρQH watts 

• Where g = 9.81 m/s², p = 1000 kg/m³, Q is the flow or discharge in m³/s, and H is the height of fall of water or head in m. 

• The efficiency of the turbine-generator assembly in a hydroelectric power plant usually varies between 50% and 90%.

• Almost 20% of the total power requirement of the world comes from hydro power

• Countries like Norway and Switzerland are almost totally dependent on hydropower.

Advantages and disadvantages of hydroelectric power

Advantages of Hydro power plants : 

Hydro power has a number of advantages:

• Water source is always available – no extra fuel is needed to be used to produce electricity

• The running costs of hydro power installations are very low.

•  Hydro power is environmentally benign.

•  The operation of Hydraulic turbine can be started or stopped in very short time.

• The hydraulic power plant is comparatively simple in concept and design.

• The operation of hydroelectric power plant is self-reliant.

• Hydro power stations are much more reliable in comparison with other power plants. 

• Modern hydro power equipment has a life of nearly 50 years.  With extraordinary maintenance the life can be increased to more than 50 years. 

• Hydroelectric plant can handle the load very easily and thus they can be used as the ideal spinning reserve in an electrical system. 

• Modern hydro-generators give high efficiency as well as handle a considerable range of load which helps improving the overall system efficiency. 

•  Manpower requirement is low; also the manpower need not be highly skilled

• The extra or bonus advantages of hydroelectric power are - they provide the means of irrigation and also contributes in flood control etc.

Disadvantages of Hydro power plants

The disadvantages are:

• Cost of hydroelectric power is a matter of great concern. Hydropower projects are capital intensive with a low rate of return

• Annual cost of hydropower installations takes a big part of the annual interest of the capital.

• The growth period of hydroelectric power projects s quite large

• The foundation and completion of a hydro power project is very hefty.  Ten to fifteen years may be needed to complete the project.

• Power generation is totally dependent on the quantity of water available, which may vary from season to season and year to year.

• These plants are often far away from the load center (most of the time in remote areas) and require long power transmission lines to deliver power — thus the cost of transmission lines are very high as well as losses in them are very significant.