SEPTA Pilot Program to Capture, Reuse Subway Energy

SEPTA recently announced a pilot project that would capture electricity generated by braking subway trains, much like a hybrid automobile produces power when it slows down.  The electricity will be stored in a large, railside battery array and reused when the train accelerates. The system is expected to reduce electrical power purchases 10 percent to 20 percent at each location of the batteries, said Andrew Gillespie, SEPTA's chief engineering officer for power.
But the system is designed to do more than capture power from the subway's dynamic braking system, said Audrey Zibelman, the chief executive officer of Viridity Energy Inc., the Conshohocken smart-grid innovator that devised the project for SEPTA.
The power-storage system is potentially so large-each battery array would store one megawatt of power that SEPTA could further reduce its electric bill by buying cheap power at night to use or resell during expensive peak hours.
 
Below is a question and answer interview with SEPTA discussing the details of this pilot program:
1) When did the pilot project officially start?


SEPTA and Viridity signed a Memorandum of Understanding (MOU) to submit a grant application to the Pennsylvania Energy Development Authority (PEDA) in June 2010, and received notice of the award in August. The project kickoff meeting will take place in September, with installation tentatively scheduled for late 2011 or early 2012 following the procurement of the storage device and all requisite engineering and design work.

2) Why is SEPTA investing $900,000 at this time to explore a battery/smart grid project?

SEPTA has been analyzing the evolution of energy storage technologies for several years and is comfortable with the readiness of such devices to meet the needs of a large, aging, urbanized transit system. The availability of resources, through PEDA as well as through the Federal Transit Administration's "Transit Investments for Greenhouse Gas and Energy Reduction" (TIGGER) program, served as the immediate impetus to move forward with project plans. Additionally, the presence of a locally based smart-grid start-up like Viridity Energy provided a unique opportunity to leverage the project to generate additional financial benefits and support the Greater Philadelphia's emerging position as a hub for advanced energy technology.

3) Has this kind of braking power/battery technology already been implemented at another subway or electrically driven transportation system in the U.S. or abroad – or would this be a first?

Regenerated braking power is widely utilized by electrified transit systems around the world, but only recently have agencies begun to pilot the use of wayside energy storage devices, and none, to our knowledge, have done so in partnership with a smart grid firm with Viridity's capabilities to optimize its use. While somewhat more common abroad (especially Europe), the only other North American transit systems that have piloted installation of wayside energy storage devices include agencies in New York City, Portland (OR), and Sacramento.

4) Would there be a significant upfront cost to expand the battery throughout your subway system?

Yes, although in the interim, SEPTA plans on aggressively pursuing additional external resources, such as a recent $2.7 million grant application to the FTA under its FY2010 TIGGER grant program.

5) How big an investment, roughly?

Devices are running at roughly $1 million each, however SEPTA anticipates that the unit cost would be substantially reduced if the devices were ordered in bulk. Additional technological advancements in the coming years also likely will reduce unit costs.

6) What kind of reactions has the announcement of the SEPTA pilot project received so far from passengers, city officials, and maybe people abroad?

The most common responses have been excitement and intrigue. Because of the newness of wayside energy storage technologies, many transit and energy industry officials and experts have expressed an eagerness to learn more about the project and closely follow its outcomes. Elected officials have endorsed the project as an example of SEPTA's innovative approach to reducing operating costs and leveraging alternative sources of revenue, noteworthy given lagging ridership and ongoing economic stagnation. City and regional leaders are particularly interested in the project's potential to serve as an additional boost to the region's emerging position as a hub for advanced energy technology, for which SEPTA is receiving increasing recognition as a multifaceted but underutilized asset.