DC power demonstrations in Japan

In recent years, information and communications technology (ICT) systems has been consuming energy increasingly rapidly all over the world. One of the more energy efficient power architectures is a DC distribution system with less power conversion stages. This DC power system has also other benefits: higher reliability, inter-connectivity to storage equipment and renewable energy sources, compactness, and so on. This paper describes the history of and trends in DC power technologies and outlines demonstration projects by NTT FACILITIES in Japan.