Blog September 19, 2018

During the early morning of Thursday, 6 September 2018, the northern Japanese island of Hokkaido experienced a significant, 6.7 magnitude-earthquake at 3:07am (local time). Out of safety concerns, nearby thermal plants shutdown generation, triggering a total blackout across the region.

The Genscape PowerRT platform shows the effects of this earthquake on the local Genscape-monitored plants and how they recovered from the blackout (Figure 1 below).

The Timeline

Our analysts saw all production stop between 3:00am – 4:00am on 6 September. Later that afternoon, hydro generation ramped up with some coal generation also restarting in the evening. Oil generation followed suit, resuming the following day.

Genscape PowerRT

Data published by the Organization for Cross-regional Coordination of Transmission Operators (OCCTO) and collected by Genscape on the Hokkaido/Honshu interconnector shows how flows from Tohoku to Hokkaido spiked around the time of the earthquake and then stopped completely (Figure 2), representing the Hokkaido blackout. The flows from Tohoku resumed from 7 September, using up the interconnector margin reserved for emergency situations. The increase in these flows match the rise in coal and oil generation in Hokkaido as seen in Genscape’s PowerRT.

Wholesale day-ahead (DA) power prices remained high in Hokkaido the day after the earthquake but decreased again during and following the weekend. In normal circumstances, Hokkaido spot prices are differentiated with the East Japan prices as only a small proportion of the interconnector capacity is usable, due to the large percentage reserved for emergency situations. The current low Hokkaido spot prices are likely due to the expanded use of the Hokkaido/Tohoku interconnector capacity, coupling Hokkaido to the East Japan spot market.

Power Output Data

Genscape was there during this historical event and is the go-to for timely intelligence into Japan power market events. Subscribers received this information in real-time allowing them to stay ahead of the curve and make informed trading decisions. For more information regarding monitored data in Japan click here or contact