CHENNAI: In a first, Tamil Nadu Green Energy Corporation Limited has floated a request for proposal for the selection of a developer to build the 1,000 MW / 6,000 MWh Vellimalai Pumped Storage Hydro-Electric Project in Kanniyakumari under the Union Ministry of Power’s tariff-based competitive bidding guidelines.
This is the first project to be developed under the public-private partnership model on a build-own-operate-transfer basis in accordance with Section 63 of the Electricity Act.
The State-run agency has also applied for terms of reference with the Union Ministry of Environment, Forest and Climate Change for environmental clearance. The Vellimalai project, planned as a closed-loop off-river system, is aimed at strengthening peak power management in the State and enabling round-the-clock integration of renewable energy.
The project will comprise four fixed-speed units of 250 MW each, with the total estimated cost, excluding transmission infrastructure, pegged at Rs 5,624 crore.
Two new off-river reservoirs will be built. The upper reservoir, proposed near Maruvattar Kannu village, will have a gross storage capacity of 4.39 million cubic metres, while the lower reservoir near Madatattuvilai village, upstream of the existing Mambazhathuraiyar dam, will have a gross storage capacity of 4.91 million cubic metres.
The project is designed to pump about 3.94 million cubic metres of water to the upper reservoir over 6.94 hours during off-peak periods. Electricity generation is planned for six hours a day using stored water, with peak annual energy generation estimated at 2,080.55 million KWh.
As a closed-loop off-river project, both reservoirs will be artificially created and will not be located on perennial rivers or streams. Water will circulate between the two reservoirs in a controlled cycle with minimal reliance on natural inflows. In contrast, open-loop pumped storage projects are connected to rivers or existing reservoirs and interact continuously with natural water systems, often resulting in higher environmental and hydrological impacts.
Land requirement for the project has been estimated at about 159 hectares, including around 62 hectares of forest land. The upper reservoir will require around 28-29 hectares, while the lower reservoir will need between 26 and 47 hectares, depending on the layout.
While the project does not involve rehabilitation and resettlement, it will require forest clearance. As the upper reservoir falls within the eco-sensitive zone of the Kanniyakumari Wildlife Sanctuary, wildlife clearance from the National Board for Wildlife will also be mandatory.
As a closed-loop off-river project, both reservoirs will be artificially created and will not be located on perennial rivers or streams. Water will circulate between the two reservoirs in a controlled cycle