This winter is likely to be Japan's first without numerical power-saving targets since 2011, sources say.

The March 2011 core meltdowns in Fukushima triggered power-saving efforts through most of the country after all 50 of the nation's viable atomic plants were shut down for safety inspections. This resulted in rolling blackouts in some cities for several months because about 30 percent of the nation's electricity had come from nuclear power.

But now that the world's third-largest economy has returned to thermal power, sources say the government might not set any electricity-saving targets this winter, when demand tends to soar.