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Hokkaido blackout partly due to power diversion failure; dialysis patients at risk

Tomato-Atsuma Thermal Power Plant operations remain suspended following a massive earthquake on Sept. 6, 2018 in the town of Atsuma in southern Hokkaido. (Mainichi)

The massive blackout that hit Hokkaido after the strong Sept. 6 earthquake was partly due to the failure of an emergency power supply system meant to feed electricity from the main island of Honshu to the northernmost island prefecture, experts say.

The power supply line connecting Honshu and Hokkaido remained intact. But the power inverter needed to convert the direct current coming from the mainland into alternating current for the grid failed because of the blackout.

Hokkaido Electric Power Co. says that even if the power supply line had worked, its maximum capacity would have been about 600,000 kilowatts, far lower than the 1.65 million kilowatts generated by the Tomato-Atsuma Thermal Power Plant that shut down after the earthquake, triggering a Hokkaido-wide power outage.

Hokkaido Electric President Akihiko Mayumi said the prefecture-wide blackout was "an extremely rare case," though he added that the possibility of all three generators at the Tomato-Atsuma plant going offline was part of emergency training scenarios. A senior Ministry of Economy, Trade and Industry official, however, said they believed that countermeasures did not exist for a full shutdown of the plant.

Meanwhile, the blackout caused serious damage to local medical institutions. According to the Ministry of Health, Labor and Welfare, power was still out at 349 hospitals across Hokkaido as of 3 p.m. on Sept. 6. They included all 34 hospitals designated as treatment hubs in times of disaster, though all were producing their own electricity with generators. Up to 62 hospitals had no running water.

Many medical facilities have had to suspend kidney dialysis services because of the power cut. According to the Japan Association of Dialysis Physicians' disaster information network, at least 17 facilities could not provide dialysis as of 11 p.m. the same day. The association is making arrangements to divert patients to hospitals capable of offering dialysis using power generators, and is asking the health ministry to make sure that enough fuel will be provided to those clinics.

Dialysis patients can suffer deadly kidney or heart failure in as little as three days without treatment. A member of the association's board of directors, Tomoyuki Yamakawa, said they had not expected such a widespread blackout. "If the power outage continues for long, offering dialysis at a limited number of facilities will be difficult," he added, suggesting that some patients may need to relocate to Honshu because commuting to the relatively few facilities in sprawling Hokkaido could be too time-consuming. Some 15,000 dialysis recipients live in Hokkaido, according to the association.

The power outage also poses risks to people using artificial ventilators at home, and the health ministry is gathering information about those patients through local municipalities and patient organizations.

The ministry has deployed disaster medical assistance teams (DMATs) to areas affected by the earthquake, including the city of Tomakomai in southern Hokkaido near the epicenter. Health minister Katsunobu Kato indicated he will send as many DMATs as possible to save lives. The Japanese Red Cross Society also dispatched an advance team to the disaster area with the help of the Japan Coast Guard.

(Japanese original by Ei Okada, Science & Environment News Department; Yuki Ogawa, Business News Department; and Kaori Gomi, Medical Welfare News Department)

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