Tamil Nadu has finalised its Battery Energy Storage System (BESS) policy after three months of discussions, with Energy Resources Minister C.T.R. Nirmal Kumar stating on October 7 that the policy and a dedicated portal will be launched soon. The announcement was made at an Indian Solar Association event in Chennai focused on the State's rooftop solar programme.
A distinctive element of the policy development is its focus beyond grid-scale storage. In July, Nirmal Kumar said the proposed framework would cover both BESS and battery recycling, with the State working with IIT Madras on research into storage technologies and recycling methods. The government has linked this approach to the expected growth of battery waste and the need to establish a recycling ecosystem ahead of the projected increase in storage deployment.
The policy is also being developed against clearly defined storage targets. Tamil Nadu has set an objective of reaching 2,500 MWh of energy storage capacity by the end of 2027 and aims to store 4% of the renewable energy generated in the State during 2029-30. The stated purpose is to reduce the operational pressure created by fluctuations in solar and wind generation, while improving the use of renewable electricity during periods of higher demand.
The State is already building a substantial BESS pipeline that could provide an implementation base for the new framework. TNGECL is developing 500 MW/1,000 MWh of standalone BESS at six TANTRANSCO substations under the State component of the central Viability Gap Funding scheme, with commissioning targeted for December 2026. A further 375 MW/1,500 MWh is planned across 11 substations with support from the Power System Development Fund, with commissioning targeted for September 2027.
Tamil Nadu has also experimented with different storage configurations rather than relying only on standalone batteries. TNERC has approved two 15 MW solar projects in Karur and Thiruvarur, each paired with a 15 MW/45 MWh BESS, to supply stored renewable electricity during peak periods. The projects were awarded through competitive bidding at a tariff of ₹4.47 per unit and are structured under a 25-year tariff framework.
Another notable feature of Tamil Nadu's storage rollout is the use of existing transmission infrastructure and substation land to reduce project costs. TNERC previously approved the leasing of land at six TANTRANSCO substations for the 500 MW/1,000 MWh BESS programme at a nominal charge of ₹1 per project per year for 15 years. The arrangement was intended to avoid higher land costs being reflected in storage tariffs.
The forthcoming portal could therefore become an important implementation layer for the State's storage ecosystem, but the government has not yet publicly disclosed its detailed functions, eligibility requirements, incentives, application process or technical provisions. These details should not be treated as final until the policy and portal are formally released. The national framework already provides Tamil Nadu with mechanisms such as BESS viability-gap funding, Power System Development Fund support and other storage-related regulatory measures, while the Central Electricity Authority has separately introduced technical requirements for large BESS projects, including grid-forming capability and black-start functionality for systems of 50 MW and above.