Hydro Power Projects: Significance & Challenges

JAN 26

Mains   > Geography   >   Resource geography   >   Dams and reservoirs


  • The discussions regarding the role of the Tapovan-Vishnugad Hydropower Project in the Joshimath land subsidence, the issue of Mullaperiyar Dam, etc. revived the debate on the benefits and threats associated with hydroelectric power projects in India.


  • India is blessed with immense amount of hydro-electric potential and ranks 5th in terms of exploitable hydro-potential on global scenario
  • As per assessment made by Central Electricity Authority (CEA) , India is endowed with economically exploitable hydro-power potential to the tune of 1,48,700 MW of installed capacity.
  • At the end of February 2020, installed capacity was about 45,700 MW.
  • The basin wise assessed potential is given below:







  • Long life and cheaper electricity:
    • Hydropower projects have a much longer life and provide cheaper electricity as there is no fuel cost and the recurring cost involved in generation, operation, and maintenance is lower than that of other sources of energy.
    • For instance, the first hydropower project in the country, completed in 1897 at Darjeeling (Sidrapong Hydroelectric Power Station), is still in operation.
  • Higher efficiency:
    • Hydroelectric plants have a higher efficiency (over 90%) compared to thermal (35%) and gas (around 50%) power plants.
  • Helps fight climate change:
    • Hydropower can help slow global warming by emitting fewer greenhouse gases (GHGs), as it is a clean and renewable source of energy.
    • For instance, hydropower prevents the emission of about 3 GT (gigatonnes) of CO2 per year, which represents about 9% of global annual CO2 emissions.
    • Also, hydropower would be crucial for India to achieve Net Zero Emissions by 2070.
  • Non-polluting and environment friendly:
    • As hydropower is a clean fuel source, it won't pollute the air like power plants that burn fossil fuels, such as coal or natural gas.
    •  In addition to this, hydroelectric projects don't generate toxic by-products.
  • Energy self-sufficiency and price stability:
    • Contrary to fuel or natural gas, river water is a domestic resource and is therefore not subject to international market fluctuations.
    • As a result, hydroelectricity plays a critical role in India's path to energy self-sufficiency. 
  • Development of backward regions:
    • Being located in remote regions, hydropower projects lead to the development of backward areas (education, medical, road communication, telecommunication, etc.).
  • Industrial development:
    • Hydroelectric projects will provide energy at a low cost, which in turn will promote industrial growth in the region.
    • For example, the Mettur dam in Tamil Nadu is a major contributor to the development of Aluminum industries in Salem. 
  • Instrument for sustainable development:
    • Hydroelectric power projects that are developed and operated in a manner that is economically viable, environmentally sensible, and socially responsible represent the best concept of sustainable development.
  • Benefits associated with dams and reservoirs for hydropower projects:
    • Water security:
      • Due to the large physiographic diversity of the country, there is a significant variation in water availability, both spatially and temporally. Hence, dams are crucial for ensuring the water security of the Country.
      • The Tehri Dam in Uttarakhand, for instance, caters to one-third of the drinking water needs of Delhi.
    • Irrigation:
      • Large dams are vital in providing year-round irrigation to farm fields.
      • For example, Bhakra Nangal, Beas projects and Indira Gandhi canal played a major role in the success of green revolution in the Punjab plains.
    • Flood control:
      • Large dams are a crucial component of all flood control projects in India. For example, the Damodar valley project, completed in 1948, still plays a crucial in controlling the floods along Jharkhand and West Bengal.
    • Ecological regulation:
      • Dams and barrages are used to control the salinity and ecological balance of delta regions.
    • Recreation & income source:
      • Dams and reservoirs are popular tourist attractions in India. They also provide income sources to local population via inland fisheries, boating and hospitality services.
      • For example, the Tehri dam reservoir, also known as Tehri Lake, is an important destination for tourists interested in boating. Also, the lake is slowly becoming a prominent hub for adventure tourism in Uttarakhand.


  • Hydropower potential in environmentally fragile regions:
    • The bulk of India’s hydropower potential lies in the Indian Himalayan states of Arunachal Pradesh (26.76 GW), Himachal Pradesh (20.63 GW), and Jammu and Kashmir (7.49 GW) etc., which are environmentally fragile regions.
    • Hydropower projects in the Himalayan region are at serious risk from earthquakes and glacial lake outburst floods and pose a grave threat to tens of thousands of people.
    • For instance, one in four hydropower projects in the Himalayas is at risk from landslides caused by earthquakes and tremors.
  • Devastating impacts on the mountain and river ecosystem:
    • Most of the hydroelectric projects in the country are planned without proper assessment of the cumulative impact of the hydropower projects on the rivers and the mountains.
    • For instance, the construction of hydropower projects would have devastating impacts on the mountains because of the blasting required to build tunnels and barrages. Eg: tunnelling by the NTPC for Tapovan Vishnugad hydropower project punctured an aquifer in 2009 in Joshimath.
    • Also, by releasing minimal water downstream, large hydroelectric projects have disrupted fish migration, leading to a loss of aquatic biota and diversity.
  • Conflicts among riparian States:
    • As water and water power are State subjects, the construction of hydropower projects are often delayed due to conflicts among riparian States, the Subansiri hydropower project is a prime example of this. 
  • Clearance issues
    • Environmental clearance:
      • Environmental clearance would remain necessary for hydroelectric projects (HEPs). Several HEPs were dropped or had their design and capacity modified due to environmental considerations
      • HEPs with capital expenditure above 1000 crore require techno-economic clearance (TEC) from the Central Electricity Authority (CEA). Clearance is given in consultation with the Central Water Commission (CWC) and takes an inordinately long time
    • Land acquisition / resettlement and rehabilitation issues:
      • The land acquisition process is elaborate, requires a public hearing, and requires the approval of the Gram Sabha. Forest clearances take time.
      • Resettlement and rehabilitation (R&R) issues are not only sensitive but also entail a substantial cost.
      • It has been observed that projects that do not anticipate adequate costs for these items at the approval stage face substantial delays and cost overruns due to issues associated with land acquisition and rehabilitation in later stages.
  • Threats posed by ageing dams:

According to the UN report, over 1,115 large dams in India will be at roughly 50 years mark by 2025. Such aging embankments across the country pose a growing threat.

    • Enhances vulnerability to disasters:
      • The older a dam, the more vulnerable it becomes to collapse due to structural decay, earthquakes, hydrostatic pressure etc. The longer a reservoir lasts, the chances of reservoir-induced earthquakes in the region increase.
      • The lower reaches of all major dams are densely populated. For eg: Three million people live downriver of the 125-year-old Mullaperiyar Dam.
    • Aggravates threat from climate change:
      • Old dams were designed and built on the basis of hydrological records in a pre-climate change era. With climate change bringing more extreme floods, aging dams threaten to become lethal.
    • Alters ecological stability:
      • Prolonged damming of rivers affects the fauna and flora in the river basins. They can lead to increased land degradation and encroachment by new invasive species.
      • Eg: Damming the river, coupled with water intensive agriculture, diversion of land and climate change has led the Kaveri delta to shrink by 20%.
    • Creates recurring conflicts:
      • Increasing concerns over dam safety has been the root cause of river water disputes in India. The most notable is the Mullaperiyar dispute between Kerala, the state under threat, and Tamil Nadu, the state upstream that operates the dam.
    • Increases cost of maintenance:
      • Ageing dams require expensive repairs. Also, siltation reduces the capacity of dams. Hence, the net return from large dams diminishes in the long run.
    • Increasing dam failures:
      • Since 1979, there were 42 instances of dam failure, the latest being Annamayya reservoir in Kadapa district of Andhra Pradesh that led to the death of at least 20 people in November 2021.


  • Hydropower projects are more than engineering ventures. They have large-scale socio-economic and environmental implications. Hence, the project management and planning team for HEPs should also include experts from social science, environment as well as communication.
  • The government should realise the fragility of the mountain and river ecosystems that face substantial threats associated with HEPs. Governments need to re-prioritize the projects based on the potential of the mountains, local and traditional knowledge, as well as the aspirations of the place. Hydropower projects should be confined to areas with the least impact on the environment. Also, the government needs to build more low-impact run-of-the-river power projects rather than destructive large dams and reservoirs.
  • Processes must be revisited to reduce the time taken for the techno-economic clearance (TEC) from the Central Electricity Authority (CEA). A unit of the CWC may be co-located within CEA itself.
  • HEPs are located in difficult and inaccessible sites. They require the development of roads and bridges for project implementation. Roads and bridges provide greater opportunities for the development of neighbouring areas. Hence, the government of India should give them increased budgetary support. Also, the process to grant financial support needs to be streamlined.
  • Like electricity, hydropower should also be brought on the concurrent list to formulate uniform policy and process for faster development.


Q. "Hydroelectric power projects that are developed and operated in a manner that is economically viable, environmentally sensible, and socially responsible represent the best concept of sustainable development." Discuss the statement with reference to the prospects and challenges associated with hydropower projects in the country.