Pennsylvania Electric Trains, Viridity to Sell Energy Back to Grid

by | Apr 30, 2012

Southeastern Pennsylvania Transportation Authority trains are on track to becoming virtual power generators, putting energy back into the electric grid as they put on the brakes.

Viridity Energy, a Philadelphia-based demand-side energy startup, says it has reached a “significant milestone” in enabling SEPTA to capture the kinetic energy created from the regenerative braking ability of trains and trolleys at a high-use propulsion substation in Philadelphia. That energy will be recycled for redeployment into the electric grid.

At this point in the installation process, the energy generated through the braking of the trains is captured and stored through an 800-kilowatt battery-backed system. Saft supplied the trackside energy storage system, and Envitech Energy provided power controls, power conversion and system integration.

SEPTA and Viridity Energy launched the pilot program in September 2010. It’s funded in part through a $900,000 Pennsylvania Energy Development Authority grant. Viridity expects a return on investment of about two to three years on the project, its managing director of technical sales and partnerships Kevin Morelock told Greentech Media.

Through this pilot, Viridity Energy will enable SEPTA to participate in PJM’s frequency regulation market, which requires response to a two- to four-second PJM signal to provide a small injection or removal of power into the grid, to ensure the grid operates at a frequency of 60 Hz. SEPTA will also be able to participate in PJM’s economic market, which is a high frequency, voluntary response program. Viridity Energy is one of the first “demand-side” participants in PJM’s regulation market.

Over the next month, the SEPTA pilot team will conduct a full-scale demonstration of regenerative capture and reuse, including regulation performance testing. Then, using Viridity Energy’s VPower platform, the project will select which market to participate in based upon market pricing, battery state of charge, and availability of regenerative energy from the trains.

In 2011 SEPTA purchased 100 hybrid-electric vehicles, bringing its total to 472 – approximately one-third of its entire bus fleet, according to its January 2012 annual report. SEPTA received $20 million in federal grants in 2011 to purchase additional hybrids in 2012 and 2013.

Also in 2011, SEPTA’s new Fox Chase Station was awarded a LEED “Silver” award for New Construction by the United States Green Building Council, the first railroad station to receive USGBC’s LEED Silver designation.

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