CHENNAI: The Tamil Nadu Power Generation Corporation Limited (TNPGCL) will soon launch Battery Energy Storage Systems (BESS) with a capacity of 200 MW at the North Chennai Thermal Power Station on a pilot basis.
Battery storage systems were so far considered options for solar and wind energy. However, the TNPGCL, for the first time, is looking to explore its use in thermal power stations to allow electricity storage during low demand.
With the state’s all-time maximum demand having touched 20,830 MW, there may not be immediate visible benefits through this pilot project. However, when scaled up in due course, it can ensure steady power supply, reduce the chances of power cuts, and avoid buying costly electricity from private companies, officials said. “This will also save money for the power utility over time,” a senior TNPGCL official said.
According to official sources, TNPGCL incurred a loss of around `2,991 crore in 2024-25 after the division of power utility into three separate entities. “If proper steps are not taken, the losses may compound this year. Installing BESS in thermal stations will help control the losses,” another official said.
Officials explained that restarting thermal units after shutting them down takes 10 to 12 hours. “But with BESS, we can avoid shutting down units frequently. The plants can keep running at full load even when demand is low, reducing operating cost,” the official said.
However, there are certain limitations. BESS cannot be used to provide continuous base load power as it does not supply electricity at a consistent long-term output. “It cannot fully replace traditional power generation,” an official added.
Once the state gives approval, the project will be taken up under the Viability Gap Funding (VGF) scheme. Additionally, the Tamil Nadu Green Energy Corporation must also give its nod and TNPGCL should sign a power purchase agreement with the power distribution company.
A senior TNPGCL official said the move follows directions from the Union Power Ministry, which has advised states to improve the efficiency of thermal stations by using battery storage. TNPGCL operates three major thermal plants - in North Chennai, Mettur, and Thoothukudi - with a total capacity of 5,120 MW, making them ideal for installing BESS.