In a state auction conducted by the Tamil Nadu Green Energy Corporation, two developers were awarded a majority of the capacity in a seven standalone Battery Energy Storage System (BESS) tender that originally targeted 375 megawatts (MW) and 1,500 megawatt?hours (MWh) of storage. The final awarded energy capacity amounted to 1,400 MWh and the MW capacity was split almost evenly between the winners, with each developer securing 175 MW and 700 MWh. Eagle Infra India secured capacity at a tariff of Rs315,000 per MW per month and OPG Power Ventures won an equivalent quantum at a tariff of Rs316,000 per MW per month.

Under the contracts the developers will be responsible for designing, financing, installing and operating the battery energy storage systems and for integrating them with the state transmission network. The facilities will draw power from the grid through TANTRANSCO and TNPDCL and will charge and discharge capacity under instructions from the state load dispatch centre to manage peak demand and grid fluctuations. The projects will operate as standalone BESS assets connected to the transmission system.

The tender imposed strict technical standards requiring the batteries to maintain 95 per cent annual availability and to complete one and a half cycles per day while delivering a minimum round?trip efficiency of 85 per cent. To improve financial viability the government will provide viability gap funding equivalent to Rs one point eight million per MWh. Developers have 18 months to complete the construction and the commissioned systems will operate under a 15?year contract.

The allocation is intended to strengthen grid stability, support renewable energy integration and provide additional flexibility to the state network as variable generation grows. The slightly different tariffs signal market dynamics and the reduction from the tender target of 1,500 MWh to an awarded 1,400 MWh reflects the final procurement outcome. Once operational the BESS assets are expected to help manage peak demand and reduce operational pressure on conventional generators.