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Hydroelectric Power Projects: Significance and Challenges

2023 NOV 12

Mains   > Geography   >   Resource geography   >   Dams and reservoirs


  • Recently, the long-delayed Subansiri Lower Hydroelectric Project suffered its latest setback after a large part of the hill on the left side of the dam collapsed into its reservoir. The deposits blocked the only functional diversion tunnel and stopped the flow of water downstream of the dam into the Subansiri River, a major tributary of the Brahmaputra.
  • Also, last month, Sikkim’s biggest hydropower project, Sikkim Urja (formerly Teesta Urja), suffered massive damage due to a flash flood.


  • 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.
  • As of March 2023, the total installed capacity of hydropower in India amounted to approximately 46.9 thousand megawatts (MW)??.



  • 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.
    • For instance, the Tehri Hydro Power Complex in Uttarakhand exemplifies how hydropower projects in remote areas can generate electricity and drive regional development.
  • 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 fisheriesboating and hospitality services.
      • Tehri Lake, formed by the Tehri Dam, is a popular spot for boating and 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 Himalayas face risks from earthquakes and glacial lake outbursts, threatening many people.
    • For instance, recently, a Glacial Lake Outburst in North Sikkim led to the destruction of the Sikkim Urja’s Teesta III dam downstream.
  • Devastating impacts on the mountain and river ecosystem:
    • Many hydroelectric projects in India are planned without fully assessing their cumulative impact on rivers and mountains, particularly the destructive effects of blasting for tunnel and barrage construction.
    • For example, tunnelling by the NTPC for the Tapovan Vishnugad hydropower project punctured an aquifer in 2009 in Joshimath.
    • Additionally, these projects often disrupt fish migration and aquatic diversity by releasing minimal water downstream.
  • 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:
      • 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 SabhaForest 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:
      • Older dams become increasingly prone to collapse from structural decay, earthquakes, and hydrostatic pressure, with prolonged reservoirs heightening the risk of induced earthquakes. For instance, three million people reside downstream 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.


  • New Hydroelectric Policy (2019):
    • Government approved a new hydroelectric policy in 2019 aimed at boosting the sector.
  • Dam Rehabilitation and Improvement Project (DRIP):
    • The project aims to improve safety and operational performance of selected dams, along with institutional strengthening the institutional mechanisms.
  • The Government had taken several policy initiatives in the past for hydropower development in the country viz., National Electricity Policy 2005, National Tariff Policy 2016, National Rehabilitation & Resettlement Policy 2007 and Right to Fair Compensation & Transparency in Land Acquisition, Rehabilitation and Resettlement Act 2013.


  • Multidisciplinary Approach:
    • 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.
  • Environmental Considerations and Prioritization:
    • The government should consider the environmental sensitivity of areas affected by Hydropower Projects, prioritizing low-impact, run-of-the-river projects over large dams and reservoirs, and align these projects with local ecology and community needs.
  • Techno-economic clearance:
    • 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.
  • Infrastructure Development and Budgetary Support:
    • Hydropower Projects in remote areas require roads and bridges for implementation, benefiting nearby regions. Thus, increased government funding and streamlined financial support processes are essential.
  • Concurrent list: 
    • Like electricity, hydropower should also be brought on the concurrent list to formulate uniform policy and process for faster development.


  • While hydropower projects in India offer substantial benefits for sustainable development, addressing the associated challenges through a comprehensive and balanced approach is crucial for maximising their potential and ensuring their long-term viability and positive impact on society and the environment.


Q. ”While hydroelectric power projects offer substantial benefits, they also present challenges that need to be carefully managed”. Comment. (15 marks, 250 words)