Regenerative Breakthrough Could Grow Battery Business

The advanced battery market is about to get much busier thanks to demand from electric vehicles, and an innovative program to capture energy from subway cars could cause a further surge. The Southeastern Pennsylvania Transportation Authority (SEPTA) won a federal grant to install an energy storage system that can capture regenerative braking energy when the subway approaches a station.

SEPTA will use the energy storage system, for which batteries similar to those used in EVs are a leading contender, to enhance the quality of power at the company’s substation in the Kensington section of Philadelphia. Some of the excess energy will be used for other purposes at the substation, while other energy will be stored and made available to the wholesale power market for grid services such as frequency regulation.

The $900,000 project is expected to have a three-year payback, and if successful could be spread to most of SEPTA’s 38 subway substations. Most of the substations were built in the 1930’s and have ample room for batteries, according to SEPTA’s Erik Johanson. He said that subway cars on the Broad Street and Frankford-Market lines have the capability to capture energy from regenerative braking.

Viridity Energy of Conshohocken will manage the project and has developed software that calculates how energy assets can be optimized to participate in grid services.

Before long, SEPTA could join a growing number of small companies looking to leverage batteries in the power market. According to Ken Huber of PJM, a regional transmission organization (RTO) operating in several eastern states, more than 40 megawatts of batteries are “in the queue” for grid applications in his company’s area.

Cumulative Installation of Lithium Ion Batteries in North America for Ancilliary Services, 2010-2015

Frequency regulation is an appropriate market for lithium ion batteries because only a small amount of energy is taken out at a time. This minimizes the impact on battery life when compared to applications that nearly fully charge or discharge a battery, such as powering a vehicle or to store wind energy produced off-peak for later use.

Huber said that a two-year trial using batteries from Altair Nanotechnologies for frequency regulation has shown less than a one percent reduction in the capacity of the batteries.

Vehicle batteries are currently being used for frequency regulation services in a project developed by the University of Delaware. Vehicle fleets maintained by organizations such as the postal service and delivery vehicles are expected to be the first participants making lithium ion batteries available for ancillary services. A successful trial in the Philadelphia subway could prompt other mass transit operators to adopt the technology to generate revenue.

Article appearing courtesy Matter Network.

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