Tamil Nadu Power Distribution Corporation (TNPDCL) has received regulatory approval to procure 600MW of solar power backed by battery storage from the Solar Energy Corporation of India (SECI) for 25 years at a discovered tariff of ₹3.12 per unit.
The Tamil Nadu Electricity Regulatory Commission (TNERC) approved the long-term procurement arrangement, which includes a 300MW battery energy storage system with a total capacity of 1,800MWh. The approval is intended to strengthen the state’s ability to meet growing electricity demand while reducing its dependence on short-term power purchases.
Under the arrangement, TNPDCL will receive 600MW of solar power during solar-generation hours. The battery system will provide 300MW during six selected hours within the evening and early-morning peak window, which runs from 6pm to 9am the following day.
The procurement will be made from SECI, with a trading margin of ₹0.07 per unit payable to the agency over and above the discovered tariff. The structure combines daytime solar generation with stored electricity for periods when demand is expected to remain significant after solar output declines.
For the state distribution utility, the long-term agreement provides a fixed procurement framework for renewable power over 25 years. TNPDCL said the arrangement would help reduce exposure to volatile prices in short-term electricity markets, improve grid stability and support compliance with renewable purchase obligations.
The storage component is central to the procurement because it allows part of the contracted solar capacity to be made available beyond daylight hours. While the solar power will be supplied during generation hours, the battery is scheduled to discharge at a specified capacity during selected peak-period hours.
The project is expected to be commissioned within 24 months of the effective date of the power purchase agreement. The approval therefore links the tariff decision to a future implementation milestone involving the execution and effectiveness of the agreement, followed by project commissioning.
The procurement comes as Tamil Nadu’s distribution utility seeks additional long-term capacity to serve demand and manage the difference between renewable generation hours and evening or early-morning consumption. The approved arrangement also places battery storage within the state’s contracted power supply framework rather than treating it only as a separate grid-support measure.
TNERC’s approval establishes the tariff, storage configuration and procurement duration for the arrangement. The next major step is the effective date of the power purchase agreement, from which the 24-month commissioning period will be calculated.
