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Tamil Nadu Floats Tender for 375 MW / 1,500 MWh Standalone Battery Storage Projects

The Tamil Nadu Generation and Electric Corporation Ltd (TNGECL) has released a tender seeking developers for seven standalone Battery Energy Storage System (BESS) projects with a combined capacity of 375 MW/1,500 MWh across the state. These systems will be implemented under the Build-Own-Operate (BOO) model and will qualify for Rs 18 lakh per MWh as viability gap funding (VGF).

Project Locations & Capacities

A total of 800 MWh of storage is slated for Coimbatore across three substations:

• Anaikadavu – 400 MWh
• Karamadai – 300 MWh
• Palladam – 100 MWh

Another 400 MWh will be deployed in Trichy at:

• Thatchankurichi – 200 MWh
• Thiruvarur – 200 MWh

Additionally, one project each is planned for:

• Madurai (Thappagundu) – 200 MWh
• Tirunelveli (N. Subbaihpuram) – 100 MWh

Bidding Details

Bidders must pay a processing fee of Rs 15 lakh plus GST, along with an earnest money deposit (EMD) of Rs 2 lakh per MW.

Successful bidders will also need to submit a Performance Bank Guarantee (PBG) worth 40% of the developer’s annual payment before the BESPA is signed.

• Bid submission deadline: December 22, 2025
• Opening of techno-commercial bids: December 23, 2025

The smallest allowable bid is 25 MW × 4 hours (100 MWh), while a single bidder can be awarded a maximum of 175 MW/700 MWh.

Operational Requirements

The selected BESS Developer (BESSD) must provide storage capacity to the buying entity, TNPDCL, enabling charging and discharging on demand.

Key conditions include:
• 15-year BESPA validity starting from full commissioning
• 1.5 full cycles per day
• 95% minimum annual availability
• BESS must support 0.25 C-rate charging and discharging
• Charging/discharging must be possible in blocks ranging from 25 MW/100 MWh to 50 MW/200 MWh

TANTRANSCO will handle land allocation, while the BESSD is responsible for system installation and grid interconnection.

Technical & Quality Standards

The EMS application software must be developed domestically in India, and the BESS must meet high quality benchmarks.

Use of refurbished battery cells is strictly prohibited.

Financial Eligibility

Bidders must meet the following financial criteria:
• Minimum net worth: Rs 40 lakh per MWh of quoted capacity
• Average annual turnover: Rs 50 lakh per MW over the last three financial years

Alternatively, bidders may demonstrate internal resource generation with a PBDIT of at least Rs 5.38 lakh per MW as of FY25 or within seven days before the bid deadline.

The tender aims to encourage the use of proven, commercially viable technologies to ensure timely project execution and minimize technical risks.