How can the nation's first blackout hitting an entire region be used as a lesson to establish a power grid that is strong in the face of natural disasters? There are many challenges to overcome.
The government-authorized investigation committee to review the major blackout caused by the Hokkaido earthquake in September has compiled an interim report incorporating an analysis of causes and measures to prevent a recurrence of an extensive power outage.
The interim report concludes that the blackout was caused by the overlapping shutdown of the Tomato-Atsuma thermal power plant and some hydraulic power stations. The overlapping shutdown led to the large scale drop in power supply, and the lowering of electrical demand by forced power outages was not enough to prevent the blackout from occurring.
Due to this, the report called for raising the power-supply threshold for forced blackouts by about 350,000 kilowatts from the current 1.46 million kilowatts. The step is expected to be effective in avoiding a major blackout.
The September blackout had an unfortunate aspect for Hokkaido Electric Power Co. (HEPCO).
HEPCO had planned to begin operation next February of a new thermal power plant using liquefied natural gas and to reinforce the power system interconnection between Honshu and Hokkaido next March. It is regrettable that Hokkaido was hit by the disaster before these plans were completed.
As to HEPCO's response to the blackout, the interim report says that no inappropriate points were confirmed.
Even so, HEPCO cannot be allowed to escape the responsibility for having failed to fulfill its mission of securing a stable power supply. Viable measures to prevent a recurrence of blackouts are called for.
Especially, it is indispensable to rectify the distorted composition of power sources in which HEPCO relied on the Tomato-Atsuma plant for half of its power supply at the time of the blackout.
Govt help called for
The interim report recommends that the Tomato-Atsuma plant be operated with reduced output. But this is nothing but a stopgap measure for the present.
There are no prospects for restarting the Tomari nuclear power station, which has the largest supply capacity among HEPCO power plants, because the Nuclear Regulation Authority's safety screening has been prolonged. The primary factor behind the delay is a difference of views on faults lying directly beneath crucial facilities of the plant. HEPCO should make utmost efforts to realize the restart of the Tomari plant.
HEPCO also should diversify its power sources through such measures as construction of new power plants. Many Hokkaido power stations are superannuated. Renovation and new construction of facilities must be promoted in a planned manner.
The investigation panel also called for further reinforcing the power interconnection system with Honshu. This is an effective step to make up for the deficiency in the power supply of Hokkaido.
However, it requires a huge amount of investment to increase power interconnection lines with Honshu. HEPCO's financial foundation is far from sufficient. Akihiko Yokoyama, chair of the investigation committee, emphasized that "all parties, including the government, are called on to study ways of sharing costs." The government is called on to study the matter seriously.
The government will compile a package of emergency measures in November concerning power supply in times of disaster. Power utilities operating in areas other than Hokkaido should also make a comprehensive inspection to ensure stable power supply in their service areas.
(From The Yomiuri Shimbun, Oct. 26, 2018)
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