Between Dec. 1 and March 31, users will be asked to turn off unnecessary lights, wear layered clothing indoors and turn the heating temperature lower.
Japan's power supply has been tight in recent years as nuclear power plants have been slow to restart after the 2011 Fukushima nuclear disaster. Rising risks that the Russia-Ukraine war could further disrupt global fuel supplies have also added pressure this year.
"The power situation remains severe though we expect to be able to secure the reserve ratio of 3% during the winter," said Yasutoshi Nishimura, Japan's industry minister, referring to the minimum generation power capacity required for stable supply.
"We won't set a numerical target, but will ask for power conservation and energy saving for the entire nation," he told a news conference.
Other measures such as rebooting idled power plants, making effective fuel procurement and encouraging power conservation through a point programme were also being implemented, he said.
Nuclear power plants have grappled with tighter regulations since the Fukushima nuclear disaster, while power supply has also been curbed by a series of closures of aging thermal power plants, in part to meet Japan's carbon (CO2) emissions reduction goals.
The resource-poor country also faces the growing risk that a prolonged Russia-Ukraine war and widening Western sanctions on Moscow could disrupt supply and cause fuel shortages.
Japan's electricity supply outlook for the winter has improved after it secured extra power generation capacity through public auctions, national grid monitor OCCTO said in September.
(Reporting by Yuka Obayashi; Editing by Ana Nicolaci da Costa)
