Hydro Power in India

Hydro-electric power is a renewable natural resource known for their almost nil GHG emission. The oldest Hydropower power plant in India is in Darjeeling District in West Bengal. Its installed capacity is 130KW and was commissioned in the year 1897.

India began with a humble 560MW capacity in 1950-51. With over 41000 MW installed capacity and 15.2% share in total installed capacity, hydropower is second largest source of electricity generation after coal. However, in these years, the relative importance of Hydro power has come down mainly because the thermal power outperformed it.

Advantages of Hydro power

Hydropower is considered to be most economical source of power. Since no fuel is burnt to produce power, there is no problem of pollution. Oil, coal and natural gas resources which can be used for producing electricity are in short supply and have implications in terms of high costs and exert greater pressure on foreign exchange resources; Hydel power can easily replace them.

Is Hydropower completely clean?

Hydropower is not completely clean because the dams produce significant amount of CO2 and Methane, both GHGs. When a large dam is built, flora gets immerged in water and rots under anaerobic conditions producing methane. Thus, whatever negative impacts of Hydropower are there, they are mainly because of alternation of surroundings of the dams, natural habitats and wildlife.

The hydropower generation is highly capital-intensive mode of electricity generation but being renewable source of energy with no consumables involved; there is very little recurring cost and hence no high long term expenditure. It is cheaper as compared to electricity generated from coal and gas fired plants. It also reduces the financial losses due to frequency fluctuations and it is more reliable as it is inflation free due to not usage of fossil fuel.

Key problems in harnessing Hydro Power

India has one of the largest hydropower potential in the world but only one fifth of that potential has been harnessed so far. The key problems include high investment costs in building large dams, dependency on hydrology, problem of environment, loss or modification of the fish habitat and displacement of the local populations. These projects have long gestation period in comparison to thermal power projects.

Types of Hydro Power Projects in India

There are two types Hydro power projects in India viz. large and small. The small hydro projects has a capacity of less than 25 MW. The small hydro projects come under the Ministry of New and Renewable Energy. Ministry of Power is responsible for large hydro projects. The small hydro projects are further classified into Micro, Mini and small projects as follows:

World’s largest Hydro-electric power station

Three gorges project in China on Yang-Yang river is the largest power station in the world having installed capacity of around 18,200 MW.

Hydel Power+Thermal Power mix: Solution of Seasonal Load Curves

Seasonal load curves of India’s regional grids match with the pattern of hydro power generation. During summer/monsoon season when the generation at hydro power plants is high, the load factor of the system is high due to heavy agricultural load. During winter, the thermal stations operating at base load and hydro stations working as peak load stations will take care of weather beating loads. Thus the operational needs of hydro & thermal stations are complimentary and the balanced mix helps in optimal utilization of the capacity.

Problem of Sedimentation in Reservoirs

Sedimentation and silting in reservoirs leads to reduction in active storage capacity; makes flood management difficult and causes damaged to turbines due to abrasive action of silt. This is a major problem of the hydropower generation. The following are some approaches to tackle sedimentation problem of reservoir:-

• Catchment Area Treatment (CAT) for reduction of silt load includes forestations of the catchment area and constructions of check dams on the tributaries and upstream of the river.
• Effective desilting arrangements for prevention of silt.
• Silt resistant equipments of withstanding the silt.
• Effective operation of the reservoir to minimize silt deposition.