SEPTA collects wasted energy from braking trains

SEPTA has embarked on a new program to capture the energy from its subway cars and trains as they come to a stop at station platforms.

Demonstrating the new technology Wednesday, Philadelphia’s transit system officials flipped the switch at a substation underneath the Market-Frankford Line in Kensington.

There’s a high whine as a train approaches the elevated station. As it slows down, energy is captured by regenerative brakes like the kind in a hybrid car. The power then travels to the old brick substation with a vaulted ceiling.

“The louder it gets,” explains project manager Kevin Morelock, “the more power that’s coming into the system. It’s getting stored in a battery.”

Morelock manages this project for Viridity Energy, the Philadelphia company SEPTA has worked with to install the energy storage system. Some of the power fed into the shipping crate full of lithium ion batteries can be sold back to the regional power grid in precise quantities, helping to keep it stable.

“These subway trains produce electricity and it’s being thrown away,” says Audrey Zibelman, CEO of Viridity. “What we’re doing now is taking that electricity and we’re recycling it; and that recycling is not only saving SEPTA money but it’s making the grid more secure.”

SEPTA didn’t put any money into the project. Funds for the pilot installation came entirely from the Pennsylvania Department of Energy and Ben Franklin Technology Partners. The total cost is $1.8 million, says Joe Casey, SEPTA general manager.

Casey says he would like to see more of this technology going into other substations throughout the transit system.