Delta Electronics India has commissioned a 6.4 MWh / 4 MW Battery Energy Storage System (BESS) at the Central Sub-station of Kolkata Metro’s Blue Line, making it the first underground metro railway in India to deploy a large-scale battery storage solution for operational resilience.
The system was inaugurated by Metro Railway Kolkata and marks a significant milestone for a broader push toward sustainable and resilient urban mobility infrastructure.
In the event of a grid failure or interruption, the system provides immediate traction power, enabling passenger-carrying trains to be safely hauled to the nearest station rather than becoming stranded mid-tunnel. Beyond emergency backup, the system also supports tunnel ventilation and environmental control functions during outages — critical for passenger safety in underground sections.
The technology at the centre of the deployment is Lithium Iron Phosphate (LFP) battery chemistry, known for its stability and long operational life — estimated at 13 to 15 years in this application. The system comprises 88 battery racks, each fitted with an integrated fire suppression system.
In addition to its emergency role, the system enables peak power management and power factor improvement, contributing to sustained energy efficiency across the network. The project is aligned with the Union Cabinet-approved National Programme on Advanced Chemistry Cell (ACC) Battery Storage.
