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HOME  > Past issues  > 2018 September 12 - 18  > Hokkaido blackout stemmed from dependence on nuclear power
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2018 September 12 - 18 [SOCIAL ISSUES]

Hokkaido blackout stemmed from dependence on nuclear power

September 16, 2018
More than a week has passed since a magnitude 6.7 earthquake shook Japan’s northern island of Hokkaido. The quake’s epicenter was located in the Iburi region in southwestern Hokkaido. The quake caused a massive blackout and people’s livelihoods have yet to return to normal. It has been pointed out that the blackout stemmed from the Hokkaido Electric Power Company (HEPCO)’s stance of clinging to the intent to reactivate the Tomari Nuclear Power Plant.

On the early morning of September 6, the strong jolts forced HEPCO’s Tomato Atsuma thermal power station, which is located near the epicenter, to stop its operation. The three-unit power station has an output of 1.65 million kilowatts which covers half of Hokkaido’s electricity demand.

Excessive dependence on large-scale power station

Electricity supply and demand must be always balanced. If the balance is disrupted, it could adversely affect power generators. After the Tomato Atsuma power plant stopped generating power due to the earthquake, the electricity balance was disturbed and as a result, other power stations in Hokkaido automatically halted their operations.

Former HEPCO worker, Mizushima Yoshihiro said, “I think the root cause of the blackout is the utility’s excessive dependence on the Tomato Atsuma thermal power station and the Tomari NPP.”

HEPCO insists that it had not foreseen that all three units at the Tomato Atsuma plant would be forced to suspend operations. However, the utility had been aware of the risks associated with heavy dependence on this large-scale thermal power station.

As the Tomari NPP went offline in 2012, the utilization rate of the Tomato Atsuma plant increased from 64% in 2010 to 85% in 2013. At that time, HEPCO said that if a major accident occurs at the Tomato Atsum plant, it could severely upset the supply-demand balance of electricity.

The Economy Ministry’s expert panel on the electricity supply and demand in its report in October 2015 gave a warning to HEPCO. The expert committee noted that the utility should implement multi-layered measures to maintain the supply-demand balance so that the company will be able to deal with a forced stoppage of power plant operations on an unprecedentedly large scale.

Build more medium- and small-sized power plants

Despite the October 2015 report, HEPCO President Mayumi Akihiko in 2016 clung to the reactivation of the Tomari NPP. In the same year, HEPCO announced that it will spend 200-250 billion yen to improve the facilities at the Tomari NPP so that the plant will meet the new nuclear safety standards.

With thermal power plants in Hokkaido aging, HEPCO has been constructing an LNG-fueled thermal power plant in the Ishikari Bay area. However, the utility in 2017 decided to delay the start of the operation of units 2 and 3 of the plant for a few years beyond what was initially scheduled.

As a reason for this decision to postpone the start, HEPCO explained that it is aware of the old age of the thermal power stations, but the electricity demand in Hokkaido did not increase as much as predicted.

Hokkai-Gakuen University professor emeritus Oda Kiyoshi said that electricity demand is not high in rural districts and that HEPCO should have supplied power to these districts by building medium- and small-sized power stations nearby. He pointed out that if the utility had designed the power grid in this way, dairy farmers in Hokkaido would not have had to discard milk because of the blackout following the latest earthquake.

Past related articles:
> Review of counter-disaster measures needed to quickly respond to serious disasters [September 10, 2018]
> Quake-prone Japan uniquely unfit for nuclear power generation [September 8, 2018]
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