The Southeastern Pennsylvania Transportation Authority (SEPTA)  unveiled its ground-breaking recycled energy and optimization project that captures the braking energy of its trains on the Market-Frankford Line and will integrate that power into the regional electric grid.

When SEPTA's trains brake at each stop to load and unload thousands of Pennsylvania passengers, the kinetic energy of the train is converted into electricity. But like many transit agencies across the country, without a method to capture that excess electricity, it could not be stored and used at a later time. Energy storage has proven to be a solution for capturing regenerative braking to provide supply savings. It has also been proven that energy storage can provide support to the electric grid through the frequency regulation market.

SEPTA will capture the regenerative braking energy of trains through a large-scale battery storage system and will deploy that energy as virtual power into PJM's wholesale power frequency regulation and energy markets.

"Through this pilot project, SEPTA will become even more energy efficient, which will help control operating costs — benefiting both customers and taxpayers. We've made our system cleaner, greener and more efficient in recent years — things like replacing traditional diesel buses with diesel-electric hybrids and installing energy-efficient lighting at stations, facilities and offices," said Joe Casey, GM at SEPTA. "These measures are helping us control costs in tough economic conditions — and making us a better neighbor in the communities we serve."

SEPTA launched the pilot project in partnership with Viridity Energy, a smart grid technology firm that specializes in electric market integration.

Saft was selected to provide the design, manufacturing and commissioning of its Intensium Max20 P System, a battery energy storage system (ESS).

Envitech Energy, a member of the ABB group, was selected to provide power controls, power conversion and system integration using its ENVISTORETM System. With these partner technologies and Viridity Energy's VPower software optimization system, the train's regenerative braking energy is being transformed into virtual power that will provide significant energy savings and new energy revenue to support SEPTA's progressive sustainability goals.

The VPower optimizer enables the simultaneous process of regenerative capture, regulation performance and energy market participation by selecting which market to participate in based upon market pricing, battery state of charge and availability of regenerative energy from the trains.

Saft lithium-ion battery technology supplies megawatt level energy storage for the project. Saft, a leader in advanced technology batteries, has provided the project with one of the first dual-purpose trackside Energy Storage Systems in the U.S.

The launch of this project was funded in part through a 2010 Pennsylvania Energy Development Authority grant program as well as support from Ben Franklin Technology Partners.

RELATED ARTICLE: Read how "Green Projects Help Transit Be More Sustainable Off the Road," from our April issue.