Metro Railway has installed a set of batteries that can chug a train stranded inside a tunnel on the north-south corridor (Blue Line) to the nearest station in the event of a power failure.
The Battery Energy Storage System (BESS) was unveiled on Wednesday at the sub-station near Central station. The CESC supplies power to Metro Railway through sub-stations.
While most train glitches are localised and linked to the train, track or signalling, the BESS is intended for large-scale power failures, a Metro official said. The backup plan was conceived in response to the nationwide blackout on July 30-31, 2012. Several Metro trains were stranded underground that day, and passengers had to be evacuated.
This new system prepares Metro Railway for a scenario where there is a complete blackout. “Previously, if there was a power failure at one sub-station, the next one could help. Now, the BESS can provide backup power if the current supplier fails,” a Metro engineer said. However, the batteries will not help in the case of engine failure, said officials.
The BESS comprises 88 racks, each storing 13 battery modules, along with four sets of power conversion system (PCS) units that function as inverters. The 4-megawatt system can power a train anywhere between Dum Dum and Tollygunge.
“The new system combines inverters and advanced chemistry cell (ACC) batteries. It can haul stranded trains from mid-tunnel to the next station during any power failure,” said a Metro engineer.
ACCs store electrical energy as chemical energy and convert it back when required. The project aligns with the Centre’s focus on next-generation energy storage infrastructure. The National Programme on Advanced Chemistry Cell battery storage was approved by the Union cabinet in May 2021, and the Metro project, approved by the Railway Board, is part of this initiative. Metro Railway is the first zone in the Indian Railways and the first Metro in the country to implement the system, a spokesperson said.
The technology uses lithium iron phosphate (LiFePO4) batteries, which replace older lead-acid batteries. “The new batteries are lighter, more powerful, and occupy only one-seventh of the space of their predecessors,” said a Metro official.
In addition to energy and cost savings, the BESS system, installed at a cost of around ₹20 crore, has a lifespan of 14 years, said the official.
“A few of the components are imported. The rest are made in India,” said Niranjan Nayak, managing director
of Delta Electronics India, which designed and installed the system.
Subhransu Sekhar Mishra, general manager of Metro Railway, unveiled the new system.