Dive Brief:

The Southeastern Pennsylvania Transportation Authority, Constellation and Viridity Energy are working to expand on a transit-based energy storage project that will help move trains out of stations and regulate frequency on the PJM Interconnection grid, the New York Times reports.

The project is an expansion of a 1.8 MW battery storage pilot program completed in 2014, which produced energy through a process called regenerative braking, one of the technologies necessary for hybrid vehicles, the Times points out.

regenerative braking, one of the technologies necessary for hybrid vehicles, the Times points out. The expanded project will be installed at seven additional SEPTA substations, adding 8.75 MW of battery storage capacity.

Dive Insight:

It's the same technology that helps hybrid vehicles work, using kinetic energy created by a vehicle braking, but this one is scaled up to help regulate frequency on the PJM grid.

While the regenerative braking concept is not new, using the stored energy from public transport to provide services to the wider grid is – and it is the type of advancement necessary to make battery projects economical right now, utilizing the ability to provide additional services to the wider power network.

Construction is slated to begin in the second quarter, with commercial operation expected later this year. Viridity Energy will provide energy market services for the project, bidding the batteries into the PJM market as frequency regulation resources.