Tokyo and 15 other prefectures from central to northeastern Japan faced tight power supply-demand situations on Tuesday, as some power plants remain offline following a powerful earthquake last week as well as larger-than-usual electricity consumption due to cold weather.
The industry ministry and Tokyo Electric Power Company Holdings Inc. warned a power outage might occur after 8 p.m., affecting around 2 to 3 million households in the areas serviced by TEPCO and Tohoku Electric Power Co., due to a smaller-than-expected decline in consumption despite their requests that power be conserved.
Later Tuesday, the ministry said that power consumption had shown a notable decline after 3 p.m. in TEPCO's service areas, apparently due to commercial users' further cuts in electricity use. It said these areas were likely to avert a blackout for the rest of the day.
The ministry and the two utilities had called on households and workplaces in their service areas to conserve energy by turning off lights when not needed and setting heating to a maximum of 20 C, with operations of some thermal power plants still suspended after last Wednesday's quake that hit the Tohoku region of northeastern Japan.
The government issued Monday night its first-ever warning over electricity availability, and it has drawn criticism over its short notice.
According to the ministry, Tuesday's tight supply was TEPCO's most severe short-term power supply situation since it engineered rolling blackouts in the wake of the March 2011 earthquake, tsunami, and nuclear disaster that hit northeastern Japan. The utility said Monday night it was not planning similar steps this time.
The two utilities had said the outage could occur Tuesday evening if hydroelectric power plants run out of water to pump in.
Prime Minister Fumio Kishida earlier called for cooperation in saving as much power as possible in the relevant areas, saying in a Twitter post, "Demand is still exceeding the target level."
Since many of Japan's nuclear reactors have been offline under stricter regulations introduced after the 2011 Fukushima Daiichi plant disaster, the country has been highly dependent on thermal power, accounting for 76.3 percent of total power generation capacity in fiscal 2020 ended in March 2021.
"In addition to the suspension of thermal power plants due to the quake, significant demand increase caused by bad weather are the factors for the strained power supply and demand situation this time," industry minister Koichi Hagiuda told a press conference, adding that rainy weather curbs solar power output.
The minister said the government issued the last-minute warning over electricity availability as it took time to examine how tight the balance of energy supply and demand would be.
"TEPCO might not have wanted to give unnecessary anxiety (to people) and waited until the very last minute when it recognized the necessity of such a warning," Hagiuda said.
Quake damage has disrupted operations of a 600,000-kilowatt unit at the Hirono Thermal Power Station in Fukushima, run by TEPCO and Chubu Electric Power Co., and Electric Power Development Co.'s 1.2-kw thermal plant in Kanagawa Prefecture.
Besides Tokyo, Aomori, Iwate, Miyagi, Akita, Yamagata, Fukushima, Ibaraki, Tochigi, Gunma, Saitama, Chiba, Kanagawa, Niigata, Yamanashi and Shizuoka were requested to cooperate in power-saving efforts.
People affected by the quake last week were also asked to cut power usage, including 74-year-old Mitsuko Kumazawa in Shiroishi, Miyagi, who is staying at her son's home in a nearby town after her home was badly damaged.
"Since it is very cold today and I have a chronic disease, I need heating, but will do all I can, such as keeping the use of lights to a minimum," Kumazawa said.
Tokyo Skytree tower, a broadcasting and observation tower, turned off its night illumination, while many news programs of public broadcaster NHK and other major TV networks were aired with dim studio lights.
TEPCO said it has since 7 a.m. received electricity from seven other power distributors, including Chubu Electric, which serves Nagoya and surrounding areas.
The industry ministry said the energy supply will remain tight on Wednesday as low temperatures are expected to continue.