TNGECL : Seeks Environmental Clearance for Large Pumped Storage Project in Kanyakumari
TNGECL: Tamil Nadu Green Energy Corporation Limited has taken a formal step toward developing a major energy storage facility in the southern part of the state, initiating the environmental clearance process for a proposed pumped storage project in Kanyakumari district. The move marks an important milestone in Tamil Nadu’s broader efforts to strengthen grid reliability as renewable power capacity continues to expand.
Environmental Review Process Begins
The state-owned company has approached the Union Ministry of Environment, Forest and Climate Change to obtain the Terms of Reference required to carry out detailed environmental impact studies. This approval is a prerequisite for securing full environmental clearance and allows the project proponent to begin comprehensive assessments covering ecology, land use, and social factors.
Project Capacity and Investment Model
Planned with an installed capacity of 1,000 megawatts, the Vellimalai pumped storage project is being developed under a public-private partnership framework. The facility is intended to provide large-scale energy storage that can absorb surplus renewable power during low-demand periods and release it when electricity demand peaks. Project estimates place the cost at about Rs 5,624 crore, excluding associated transmission infrastructure.
Closed-Loop Design for Grid Stability
The project is designed as a closed-loop, off-river pumped storage system, meaning it will operate independently of rivers or natural streams. Such systems are increasingly seen as effective tools for managing the variable nature of solar and wind power. By recycling water between two reservoirs, the plant is expected to help smooth fluctuations in power supply and improve overall grid stability.
Technical Configuration and Output
According to project planning documents, the facility will comprise four fixed-speed generating units, each with a capacity of 250 megawatts. Together, they will deliver a total capacity of 1,000 megawatts. During daily operations, water will be pumped uphill during off-peak hours and released to generate power during periods of high demand. Annual peak energy generation is projected at approximately 2,080.55 gigawatt hours.
Reservoir Locations and Water Cycle
Two new off-river reservoirs form the core of the system. The upper reservoir is proposed near Maruvattar Kannu village and is designed to hold roughly 4.39 million cubic metres of water. The lower reservoir, planned near Madathattuvilai village upstream of the existing Mambazhathuraiyar Dam, will have a slightly higher gross storage capacity of about 4.91 million cubic metres.
Daily Operating Schedule
Under the proposed operational cycle, close to 3.94 million cubic metres of water will be pumped from the lower reservoir to the upper reservoir over nearly seven hours during off-peak periods. Power generation is expected to take place for around six hours each day, timed to coincide with peak electricity demand. This cycle allows the same volume of water to be reused repeatedly with minimal external input.
Environmental Considerations and Impact
TNGECL has highlighted that the closed-loop configuration significantly limits environmental and hydrological impacts compared to open-loop pumped storage projects that depend on rivers. Because the system does not require continuous natural inflows, its effect on downstream water availability and aquatic ecosystems is expected to be lower.
Land Use and Regulatory Clearances
The project will require approximately 159 hectares of land, including around 62 hectares classified as forest land. The footprint covers reservoirs, underground powerhouses, water conveyance systems, access roads, labour facilities, and designated muck disposal areas. While no rehabilitation or resettlement is anticipated, forest clearance will be necessary.
Wildlife and Eco-Sensitive Zone Approvals
An additional layer of scrutiny applies because the proposed upper reservoir lies within the eco-sensitive zone of the Kanyakumari Wildlife Sanctuary. As a result, clearance from the National Board for Wildlife will be mandatory before construction can proceed. Authorities will assess potential impacts on local biodiversity as part of the approval process.