Energy-harvesting technology lets the train take the strain

One of the oldest rail lines in the US will soon become home to a cutting-edge energy-harvesting technology that promises to recover the energy lost by braking trains and feed it into the grid.

Philadelphia-based smart grid firm Viridity Energy and the Southeastern Pennsylvania Transportation Authority (SEPTA) announced last week that they have been awarded a $900,000 (£583,000) grant by the State of Pennsylvania that will allow them to complete an ambitious pilot project.

Precise details of how the technology works have not been announced, but Viridity said that it was preparing to deploy a large-scale battery near a portion of the Market-Frankford Line where energy from regenerative braking of trains will be captured. The stored energy will be fed into the grid during periods of peak demand.

The company said that the project should help SEPTA cut its carbon footprint by 1,258 tonnes a year while also helping to improve grid reliability.

Audrey Zibelman, president and chief executive of Viridity Energy, said that power purchase agreements would also allow the rail operator to open up a new revenue stream. "This project is a perfect example of how smart grid innovations and advances in technology can effectively be paired with revenue opportunities from competitive energy markets to yield substantial economic, operational and environmental benefits to all the parties involved," he said.

The company hopes that the pilot will act as a forerunner for similar projects across the US rail network and if it proves successful, it plans to deploy the system at all SEPTA's 38 substations.