Table of Contents
THE CONTEXT: The recent landslide in Sikkim affecting the Teesta-5 hydropower station raises concerns about the vulnerability of hydroelectric projects in the region, especially following the devastating impact on the Teesta-3 project last October. This recurring pattern of natural disasters impacting crucial power infrastructure highlights the need for a thorough reassessment of hydropower development in the area.
MAP OF TEESTA RIVER:
ABOUT TEESTA RIVER: The Teesta River, with a total length of 414 kilometers, flows through the Indian states of Sikkim and West Bengal before entering Bangladesh. In India, the river covers approximately 305 kilometers, with around 172 kilometers flowing through Sikkim and the remaining 133 kilometers traversing West Bengal. The river then continues its journey in Bangladesh for about 109 kilometers before merging with the Brahmaputra River. The Teesta plays a crucial role in the regions it passes through, supporting irrigation, hydropower, and biodiversity.
MAJOR HYDROELECTRIC PROJECTS ON THE TEESTA RIVER:
- Teesta-V Dam: Located in Dikchu, Sikkim, this project generates 510 MW of electricity and is operated by NHPC Limited.
- Teesta III Dam: Situated in Chungthang, Sikkim, it is one of the largest hydropower plants in India with a capacity of 1,200 MW, developed by Teesta Urja Limited.
- Teesta Low Dam III and IV: These projects are in West Bengal, with capacities of 132 MW and 160 MW respectively, both managed by NHPC Limited.
- Teesta VI Dam: Under construction in Sikkim, this project is expected to generate 500 MW and is managed by NHPC.
MANAGEMENT OF HYDROELECTRIC PROJECTS IN INDIA:
- Historical Management: Before 1989, all hydropower projects were under the Ministry of Power. In 1989, projects up to 3 MW were transferred to MNRE. In November 1999, projects up to 25 MW were entrusted to MNRE.
- Project Size Classification: Ministry of Power oversees large hydropower projects (above 25 MW capacity). MNRE is responsible for small hydropower projects (25 MW capacity and below).
- Focus Areas: Ministry of Power focuses on large-scale hydroelectric projects for major power generation. MNRE concentrates on small/mini hydel projects, often in hilly regions or utilizing irrigation canals.
- Policy and Promotion: Ministry of Power develops policies for large hydropower projects as part of overall power sector planning. MNRE has taken initiatives specifically for small hydro promotion, including implementing UNDP-GEF assisted projects and IDA credit line projects.
- Potential Assessment: MNRE, through the Hydro and Renewable Energy Department (HRED) of IIT Roorkee, has assessed the potential for small/mini hydel projects (21,133 MW from 7,133 sites).
- State Coordination: MNRE gives focused attention to states with high small hydro potential like Arunachal Pradesh, Himachal Pradesh, Jammu & Kashmir, and Uttarakhand.
- Renewable Energy Integration: MNRE manages small hydro as part of its broader renewable energy portfolio, alongside solar, wind, and other renewable sources. Ministry of Power deals with hydropower in the context of overall power generation and grid management.
- Funding and Support Mechanisms: MNRE has specific schemes and support mechanisms for small hydro development. Ministry of Power handles larger financing and policy frameworks for major hydroelectric projects.
THE ISSUES:
- Natural Disaster Vulnerability: In October 2023, a Glacial Lake Outburst Flood (GLOF) destroyed the Chungthang dam of the Teesta-3 power station, reducing its power output by 90%. On August 20, 2024, a landslide damaged six houses and a building of the NHPC at the Teesta-5 hydropower station in Gangtok. The frequency of landslides in the region has notably increased since 1995, with another significant rise starting in 2007.
- Environmental Impact: Out of 47 initially proposed projects along the Teesta River in Sikkim and West Bengal, only five are currently operational, with 16 in various stages of consideration. The Teesta originates from Tso Lhamo Lake at an elevation of 5,280 meters in north Sikkim and flows through Sikkim, West Bengal, and Bangladesh before joining the Bay of Bengal. Unplanned construction and hydroelectric dams have made the Teesta more flood prone.
- Cost-Benefit Analysis: The Teesta-V hydropower station (510 MW) in Sikkim was rated as an example of international good practice in hydropower sustainability by an independent assessment. However, the Teesta-3 project (1,200 MW), once the largest in Sikkim, is now operating at only 10% of its original capacity due to the GLOF damage. The Sikkim state government requested 200 billion Indian rupees from the central government to restore damage caused by the 2023 GLOF.
- Poor design choices and catastrophic failures: The Teesta-3 project developers chose a cheaper concrete-faced rock fill dam instead of a more durable concrete gravity dam, contributing to its complete destruction during the GLOF. A hardfill dam has much greater weight and a longer length for shear resistance compared to a conventional gravity dam, highlighting the importance of proper design choices.
- Public Perception and Trust: Local Lepcha communities were reportedly shunned for protesting the Teesta V project, despite raising concerns about GLOF impacts. Neither employment opportunities nor energy or revenue benefits have reached the people of Kalimpong and Sikkim from these projects. A study in Sikkim found that hydropower projects had significant impacts on villagers who were not physically displaced, affecting their sustainable livelihoods.
THE WAY FORWARD:
- Comprehensive Environmental Impact Assessments: Include detailed geological and hydrological studies, considering long-term climate change impacts A study by Erlewein (2013) in Himachal Pradesh found that traditional EIA methods struggle to keep up with rapid hydropower development. The World Bank recommends Strategic Environmental Assessments (SEAs) to address broader impacts of widespread hydropower development. In Norway, cumulative impact assessments are mandatory for hydropower projects in the same river basin.
- Improved Dam Design and Construction Standards: Mandate the use of concrete gravity dams instead of concrete-faced rock fill dams for better stability. The Teesta-3 project’s concrete-faced rock fill dam was completely washed away, highlighting the need for more robust designs. China’s Wudongde Dam uses intelligent systems to monitor structural health and adjust operations in real-time.
- Diversification of Energy Sources: Invest in alternative renewable energy sources such as solar and wind power. Promote small-scale, run-of-river hydropower projects with lower environmental impacts. India aims to install 175 GW of renewable energy capacity by 2022, including 100 GW from solar. Bhutan’s 720 MW Mangdechhu run-of-river project has minimal environmental impact and high efficiency. The International Energy Agency projects that solar PV will account for two-thirds of global renewable capacity additions by 2024.
- Integrated River Basin Management: Establish a joint river basin management authority involving all stakeholders Develop a comprehensive water allocation plan considering all uses (energy, agriculture, ecology). Spain’s Ebro River Basin Authority successfully balances water needs for agriculture, urban use, and hydropower.
- Community Engagement and Benefit-Sharing: Implement skill development programs for residents to participate in project operations Nepal’s Community Rural Electrification Programme has connected over 550,000 households to the grid through community-owned distribution. Laos’ Nam Theun 2 project allocates US$1 million annually for community development initiatives. A study in India found that community-based mini-grid projects are especially effective when community members are active stakeholders.
THE CONCLUSION:
To address these challenges, it is imperative that environmental impact assessments for hydropower projects in the region provide clear and accurate cost estimates, including potential risks. By doing so, public confidence in these projects can be strengthened, and their environmental sustainability can be ensured, leading to more resilient and responsible hydroelectric development.
UPSC PAST YEAR QUESTION:
Q. Dam failures are always catastrophic, especially on the downstream side, resulting in a colossal loss of life and property. Analyze the various causes of dam failures. Give two examples of large dam failures. 2023
MAINS PRACTICE QUESTION:
Q. Critically examine the issues surrounding hydropower development in ecologically sensitive regions and suggest measures to ensure a more sustainable approach to energy production in such areas.
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