Households and businesses in the Tokyo area on Saturday began a period of power conservation that will last through to August amid forecasts of tight supplies.
The central government issued a request based on the projection that the reserve power capacity rate in the region served by Tokyo Electric Power Company Holdings in July could drop to 3.1%, slightly above the lowest level for maintaining a stable supply, if a once-in-a-decade level of extreme heat grips the area.
Since electricity demand could swing about 3% from the anticipated level, it is necessary to secure at least a 3% reserve, according to the Ministry of Economy, Trade and Industry.
The rate is projected to improve to 4.8% in the region in August, while that in other regions is expected to stay above 5% in July and August, a ministry official said.
Last year, the government issued a nationwide power-saving request from July to September, but the latest request only targets the area served by Tepco.
Last summer's request was the first issued since fiscal 2015 when all of the country's nuclear reactors were offline in the wake of the Fukushima nuclear power plant disaster in 2011.
The country's weather agency has predicted Japan may face a hotter summer due to the influence of the El Nino climate pattern — warmer water in the central and eastern Pacific — as well as climate change.
Besides the nation's capital, Tepco serves Kanagawa, Saitama, Chiba, Tochigi, Gunma, Ibaraki and Yamanashi prefectures, as well as part of Shizuoka Prefecture.