Power Grid Corporation of India (POWERGRID) has issued tenders to set up 25 MW/100 MWh and 100 MW/400 MWh battery energy storage system (BESS) projects across Tamil Nadu. These projects will receive viability gap funding support.

These tenders are associated with the invitation to select partners for setting up 375 MW/1,500 MWh standalone BESS projects across seven locations in the state.

The BESS projects will be set up at either the Anaikadavu, Karamadai, and Palladam substations in Coimbatore; the Thatchankurichi and Thiruvarur substations in Trichy; the Thappagundu substation in Madurai; or the N.Subbiahpuram substation in Tirunelveli.

Bids must be submitted by January 30, 2026. Bids will be opened on the same day.

Bidders must furnish a tender document fee of ₹25,000 (~$272.34).

The BESS projects will include the battery system, power conversion system and transformers, and complete 33 kV medium voltage bus work. The projects will have four hours of operation per day on an on-demand basis with one and a half charging/discharging cycles.

Selected bidders must provide comprehensive project facility maintenance for 15 years.

The BESS projects must be commissioned within 15 months.

Bidders must comply with any of the following requirements as a prime contractor:

• They must have supplied, erected, tested, and commissioned grid-connected BESS systems with at least 10 MWh cumulative capacity
• They must have supplied, erected, tested, and commissioned at least one solar or wind project with a minimum capacity of 50 MW
• They must have erected, tested, and commissioned at least two AIS^ circuit breaker-equipped bays of a minimum 132 kV voltage level in one substation or switchyard

These projects must have been operational for the last seven years from the bid submission end date.

Alternatively, bidders must be battery manufacturers who have supplied at least 50 MWh of batteries for stationary grid applications during the previous three years from the bid submission end date.

Bidders must have a positive net worth during the preceding three financial years.

Bidders must have a minimum average annual turnover of ₹1.4 billion (~$15.3 million) for the 25 MW/100 MWh project and ₹5.62 billion (~$61.18 million) for the 100 MW/400 MWh project.

Bidders must demonstrate liquid assets and/or evidence of access to, or availability of credit facilities worth at least ₹234 million (~$2.55 million) for the 25 MW/100 MWh project and ₹936 million (~$10.2 million) for the 100 MW/ 400 MWh project.

Recently, POWERGRID floated two tenders to set up standalone BESS of 187.5 MW/750 MWh each at two of Transmission Corporation of Telangana’s Maheswaram and Choutuppal substations.