TOKYO—As Japan slowly comes to grips with the devastation created by its earthquake and tsunami and ensuing nuclear crisis, a debate is emerging in business and political circles about how to do more with less electricity—or just do less.

After years of debate, Japanese policy makers have finally begun seriously to consider for the first time in six decades instituting daylight-saving time this summer, which would reduce energy demand in the early mornings and evenings. Japanese companies also are weighing reducing hours worked—and...