Research Project Information

Research Project Summary Information

Wayside Ultra-Capacitor Energy Storage System for Transit Applications(ST10388-1)

Electrical Power WorX Corporation


Electrical Power WorX (EPX) is a relatively new, upstate NY company comprised of engineering professionals with substantial electrified rail propulsion experience. EPX has recognized the potential for utilizing wayside electrical energy storage systems to achieve energy savings through the capture and more effective use of regenerative braking energy in electrified rail transit systems, such as the NYC Transit subway system. Typically, without a means of storing the braking energy, an accelerating train needs to be in close proximity of a decelerating train for this energy to be utilized. With wayside energy storage, either through flywheels, ultra capacitors, batteries, or a combination of technologies, the regenerative braking energy can be employed much more practically and effectively. EPX has recognized the advantages of ultra capacitors for this application and are pursuing the development and ultimate commercialization of electrified rail wayside energy storage systems based on this technology. The NYC MTA is North America’s largest electrified rail transportation network, and is in the midst of a major initiative to increase sustainability, including energy efficiency. Reduction of traction (railcar propulsion) energy is one of the major initiatives in this activity, and the use of energy storage to enhance the capture and use of regenerative braking energy of the railcars is a key focus area.

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Project Description

This objective of the project was to define, design, fabricate and factory test a 1 MWe ultra capacitor based wayside energy storage system for electrified rail transit applications. The project started with a detailed transit system application analysis and requirements definition, followed by the design of the ultra capacitor storage system hardware, and finishing with prototype system fabrication and factory test.


The most current and comprehensive analysis of the potential impact of energy storage technology in the MTA system is contained in the report of the MTA Sustainability Commission Traction Power report, which states a current baseline annual electrical power use by MTA of 2150 GWh for traction power alone. The report further calculates the maximum electrical energy saving potential of regenerative braking with energy storage is 707 million kWh annually , yielding an estimated annual reduction of 304 million kg of CO2. In addition to the energy savings, energy storage technology such as this system is also able to show reductions in peak demand, provide voltage support for third rail operations, and provide emergency motive power for railcars when utility power s lost.

Project Results

The project was successful in all aspects of the objectives and project deliverables. A full application analysis was completed and requirements specifications developed, based on consultation with, and concurrence of the MTA/ NYCT. A prototype storage system was designed, with full design documents prepared. A unit was constructed, and factory tested in accordance with the established testing protocols that were developed. The Contractor is currently planning to pursue demonstrating the 1 MWe ultra capacitor unit and companion electrical control unit at a suitable site within the NYC MTA system.


Electrical Power WorX Corporation
646 Clark Rd
Alfred Station, NY 14803

Principle Investigator

Marcus Emerson

Universities Involved


Project Type:

Product Development

Technologies Types:

Energy Storage

NYSERDA Contact Information

Frank Ralbovsky


R&D -Transport & Power Systems

Contract Details

Start Date: 1/11/2010
Project Status: Active
Contract Number: ST10388-1

Last Updated: 2/8/2013 6