The system will enable Septa to recover train braking energy through the 700V dc third rail electrification system and reduce energy consumption, while simultaneously generating revenue by returning unused power to the local grid.

Enviline will be installed at Griscom substation, and the system is already in operation at Letterly substation, where it was installed in 2012 in a joint project between ABB, Viridity Energy, and Saft Battery which was funded with the aid of a $US 900,000 grant from Pennsylvania Energy Development Authority.

In 2012 Septa secured a $US 1.44m grant from the Federal Transit Administration (FTA) to test the viability of an alternative battery technology to the one used at Letterly. The Griscom installation will therefore use a hybrid storage system, combining supercapacitors with batteries, which ABB says will recover more braking energy, produce higher revenues from frequency regulation, and extend the life of the batteries.

Septa says the results of testing at Griscom substation will be made available to other public transport operators in the United States to help them make better informed decisions about how wayside energy storage might benefit their own operations.