Tamil Nadu has unveiled a dedicated policy to scale up battery storage, as the state looks to steady a grid that already carries one of India's largest renewable fleets. The Tamil Nadu Battery Energy Storage Systems Policy, 2026 — dated October 28 — targets at least 2.5 GW / 10 GWh of storage capacity during its three-year validity, The Hindu BusinessLine reported.

Under the policy, every new solar and solar-hybrid project of 1 MW and above must install battery storage equal to at least 10 per cent of the project's installed capacity, with a four-hour discharge duration. The requirement applies to projects that apply on or after the policy's notification date, or are commissioned on or after April 1, 2027.

Source: The Hindu BusinessLine

To draw in private investment, eligible standalone and co-located storage projects commissioned during the policy period will be considered for a 100 per cent waiver of transmission and wheeling charges for 10 years from commissioning — subject to approval by the Tamil Nadu Electricity Regulatory Commission (TNERC). The state utility TNPDCL will procure 2,500 MW / 10,000 MWh of storage through competitive bidding, at prices discovered through the bidding process and approved by TNERC.

The policy covers standalone storage, storage co-located with generation plants or consumer networks, and is aimed at building a Storage-as-a-Service market, cutting renewable curtailment and improving grid stability, ESG News reported, quoting the Energy Department's notification.

Source: ESG News

Tamil Nadu currently has about 29.8 GW of installed renewable capacity, including around 14.5 GW of solar and 11.6 GW of wind, according to the policy documents. The policy stays in force for three years from notification, or until 10 GWh of storage capacity is commissioned under it, whichever is earlier.