A power saving system using a plurality of flexible display devices placed on various places is provided. A structure of a bendable portion in a display device is improved. Specifically, a wiring partly including a metal nanoparticle is used. Openings are formed in an insulating layer so that the wiring becomes substantially longer by meandering in cross section. When a plurality of openings are formed and aligned, a portion that is easy to bend is formed along the line where they are aligned. A plurality of display panels are used for one display portion. The flexible display portion can be provided on a surface, specifically, a curved surface of furniture such as a chair or a sofa.