Tamil Nadu's 1,000 MW Green Energy Storage Project Seeks Environmental Nod

The 1,000 MW pumped storage project, proposed under the public-private partnership (PPP) model, is positioned as a key infrastructure addition to support Tamil Nadu's rapidly expanding renewable energy capacity and improve grid stability during peak demand hours.

Planned as a closed-loop, off-river pumped storage system, the Vellimalai project is intended to play a critical role in balancing intermittent renewable energy sources such as solar and wind. The facility will consist of four fixed-speed units of 250 MW each, taking the total installed capacity to 1,000 MW. The estimated project cost, excluding transmission infrastructure, is Rs 5,624 crore. Once operational, the project is expected to significantly enhance peak power management and facilitate round-the-clock availability of clean energy in the state.

Project documents indicate that the scheme will involve the construction of two entirely new off-river reservoirs. The upper reservoir is proposed near Maruvattar Kannu village with a gross storage capacity of about 4.39 million cubic metres.

The lower reservoir, planned near Madathattuvilai village and located upstream of the existing Mambazhathuraiyar Dam, will have a gross storage capacity of around 4.91 million cubic metres.

Under the proposed operating cycle, nearly 3.94 million cubic metres of water will be pumped from the lower reservoir to the upper reservoir during off-peak hours over a period of approximately 6.94 hours. Power generation will take place for about six hours a day during peak demand periods, with annual peak energy generation estimated at 2,080.55 gigawatt hours (GWh).

As a closed-loop off-river system, the project does not rely on perennial rivers or natural streams. Water will be circulated between the two reservoirs in a controlled cycle, with minimal dependence on natural inflows.

TNGECL has pointed out that this design substantially reduces environmental and hydrological impacts when compared to open-loop pumped storage projects, which are directly linked to rivers or existing reservoirs.

The total land requirement for the project is estimated at around 159 hectares, including nearly 62 hectares of forest land. This includes land for reservoirs, water conductor systems, an underground powerhouse and adits, approach roads, muck disposal areas, labour camps and colony areas.

While the project does not involve rehabilitation and resettlement, it will require forest clearance. Since the upper reservoir falls within the eco-sensitive zone of the Kanyakumari Wildlife Sanctuary, clearance from the National Board for Wildlife will also be mandatory.

- IANS