The Tamil Nadu Green Energy Corporation has initiated a tender for seven standalone battery-energy storage systems totalling 375 MW / 1,500 MWh, with block sizes ranging from 25 MW / 100 MWh up to 175 MW / 700 MWh per bidder. 

The battery systems must deliver 1.5 full cycles daily, maintain 95% annual availability, and achieve at least 85% AC-to-AC round-trip efficiency. 

Developers will sign 15-year Battery Energy Storage Purchase Agreements (BESPAs) and receive viability-gap funding in three phases aligned to financial close, COD, and one year post-COD. 

This move is part of Tamil Nadu’s broader strategy to bolster grid flexibility, enable deeper renewable penetration, and build a mature domestic energy-storage ecosystem.