DOE Global Energy Storage Database

Woojin Industrial Systems has completed installation of its energy storage system (ESS) ultracapacitor-based braking energy recuperation systems in seven Metro stations in Seoul, Daejon, Incheon and the Korea Train eXpress (KTX) high-speed rail depot in Seoul. Beginning with installation of demonstration systems in 2009 under a contract with the Korean federal government's Korean Railroad Research Institute (KRRI), Woojin and rail system operators have achieved grid power consumption savings of more than 20 percent and realized additional benefits in the form of system voltage stabilization that reduces power infrastructure requirements and helps to ensure uninterrupted operation. The recuperation systems, ranging from 750 to 1,500 volts, employ Maxwell ultracapacitors to absorb energy during rail vehicle braking and deliver the stored energy to the vehicles' electric motors for propulsion and to stabilize voltage throughout the system. Each installation employs up to 200 of Maxwell's 48-volt multi-cell ultracapacitor modules. Based on their positive experience to date, Woojin and rail system operators are planning several additional installations in 2014 and 2015.