Technology development has been promoted aiming for an environment-friendly traction power supply system for railways. Among other things, a stationary energy storage system using lithium ion batteries for hybrid cars has been put into practical use since 2007. This device temporarily stores regenerative power generated from an train when it is stopped and the power is able to be applied for energy saving, measures against regeneration canceled and compensation for a voltage drop. The implementation planning for a stationary energy storage system (SESS) has been popular in recent years. The implementation of the SESS at railway companies can contribute to the reduction in the global warming gas emissions.