Tamil Nadu Launches 1,000 MW Pumped Storage Project in Kanyakumari

The state-run Tamil Nadu Green Energy Corporation Limited (TNGECL) has floated a Request for Proposal (RFP) to select a developer for the project under the Union Ministry of Power's tariff-based competitive bidding guidelines. The proposed project will be the first pumped storage initiative in Tamil Nadu to be implemented under a public-private partnership (PPP) model on a build-own-operate-transfer (BOOT) basis in accordance with Section 63 of the Electricity Act.

The model allows private developers to construct and operate the facility for a fixed period before transferring it back to the government.

Officials said the Vellimalai project is a key component of the state's strategy to support the growing share of renewable energy, such as solar and wind. Pumped storage facilities act as large-scale energy storage systems, enabling surplus power generated during off-peak hours to be stored and released during peak demand.

The project, estimated to cost Rs 5,624 crore excluding transmission infrastructure, will consist of four fixed-speed turbine units of 250 MW each, with a total installed capacity of 1,000 MW and a storage capacity of 6,000 MWh.

Designed as a closed-loop off-river pumped storage system, the project will involve the creation of two artificial reservoirs rather than relying on existing rivers or dams. The upper reservoir, planned near Maruvattar Kannu village, will have a gross storage capacity of 4.39 million cubic metres, while the lower reservoir, proposed near Madatattuvilai village upstream of the Mambazhathuraiyar dam, will store 4.91 million cubic metres of water.

During off-peak hours, approximately 3.94 million cubic metres of water will be pumped to the upper reservoir over 6.94 hours using surplus electricity. The stored water will then be released to generate power for around six hours daily, with the project expected to produce about 2,080.55 million units of electricity annually during peak demand periods.

Unlike open-loop pumped storage projects that depend on natural rivers and reservoirs, the closed-loop design minimises hydrological impacts by circulating water between the two reservoirs in a controlled system with minimal natural inflow.

The project will require about 159 hectares of land, including around 62 hectares of forest land. While it does not involve any rehabilitation or resettlement of local communities, the project will require forest clearance and environmental approvals.

TNGECL has already applied to the Union Ministry of Environment, Forest and Climate Change for Terms of Reference (ToR) to begin the environmental impact assessment process. Since the proposed upper reservoir lies within the eco-sensitive zone of the Kanniyakumari Wildlife Sanctuary, clearance from the National Board for Wildlife will also be required before construction can begin.

Once completed, the Vellimalai project is likely to play a crucial role in stabilising the grid and enabling round-the-clock renewable energy supply in Tamil Nadu.

- IANS