SEPTA, Constellation, and Viridity Energy to deploy 8.75MW energy storage system to capture and reuse subway train braking energy
An 8.75MW battery storage network which will capture and reuse the energy created by braking subway cars will help Southeastern Pennsylvania Transportation Authority (SEPTA) reduce operating costs, ensure energy resiliency, and support the stability of the electrical grid.
Constellation, a subsidiary of Exelon Corporation, will fund, own, and operate the 8.75MW battery storage network, deployed at seven SEPTA substations. The network is designed to use stored energy to power trains as they accelerate from stations and can provide emergency generation for trains in the event of a power outage. ABB will provide engineering, procurement, construction and operations services to Constellation for the project. Saft will provide the lithium-ion battery technology.
Recovery and reuse of braking energy is well proven and is now widely used in hybrid electric vehicles and, more recently, by bus operators the world over. The solution installed by SEPTA is based on ABB’s Envistore Regenerative Energy Storage System, which usually uses capacitors to store braking energy and release it again shortly afterwards to boost train acceleration.
For SEPTA’s application, the capacitors were replaced with high performance Saft Intensium Max20P Li-ion battery systems. The Max20P system, packaged in 20-foot containers, comprises Saft Synerion 24 Li-ion battery modules, power conditioning, communications interface, battery management, cooling and fire prevention systems.
The energy recovery and storage system is complemented with software that enables SEPTA to monitor energy prices and sell the stored energy back to the grid when energy prices are high, usually during peak hours and in hot weather, so helping reduce operational costs and creating a new revenue stream.
An expansion of SEPTA’s 1.8 MW battery storage pilot program completed in 2014, the new network brings the agency’s total battery storage capacity to more than 10 MW. The pilot recovered an average 1.1 MWh on weekdays and 1.5 MWh on weekends.
The expansion project, which is among the first commercially deployed battery storage systems in a transit operation, requires no upfront capital investment from SEPTA and will be financed through a 20-year battery services agreement with Constellation.
As a competitive energy supplier, we aim to provide our customers with the best long-term economic and business solutions for how their energy is produced and supplied. This battery storage network, along with $26 million in guaranteed savings from efficiency improvements Constellation is implementing for SEPTA, will help SEPTA deliver on its budget and energy resiliency goals.—Gary Fromer, senior vice president of distributed energy at Constellation
The stored energy will help to balance electric load on the PJM Interconnection, the regional transmission organization that manages the movement of wholesale electricity in 13 states and the District of Columbia. Viridity Energy will provide energy market services for the project, bidding the batteries into the PJM market as frequency regulation resources to help match generation with demand and maintain the desired electrical frequency on the grid.
Construction activities are scheduled to begin in the second quarter of 2016 with estimated commercial operation in late 2016.