Wind farms on Hokkaido, the northernmost of Japan’s main islands also appear to have withstood an earthquake on the morning of 6 September, the JWPA said.
However, a 600kW Mitsubishi Heavy Industries (MHI) turbine installed in Hyogo prefecture on the country’s main island of Honshu was toppled during Typhoon Cimarron, which hit Japan towards the end of August.
Then, during Typhoon Jebi in early September, a 2MW Enercon turbine in Hino-misaki in Wakayama prefecture was blown over, and a blade of a 1.5MW GE turbine in Hirokawa-cho, Wakayama was damaged.
Enercon confirmed that an investigation is under way.
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Jebi was the strongest typhoon to hit Japan in 25 years, killing at least 11 people and has caused widespread damage and disruption since it hit on 4 September.
One 600kW turbine installed in a park in the island city of Awaji in Hyogo prefecture was knocked down during Typhoon Cimarron on 24 August.
The turbine, an MWT-S600 MHI model, had been installed in 2002 to generate power for facilities in the park and was decommissioned following a lightning strike in May 2017.
Another MWT-S600 turbine installed near Kansai Airport in Wakayama prefecture in April 2003 survived both typhoons, the JWPA stated. This suggests the turbine’s design was not the cause of its falling, the organisation added.
The JWPA also pointed out the turbine had been installed prior to wind turbine safety regulation changes in the country’s Construction Act in June 2007.
Regulations had been tightened following Typhoon Maemi struck Japan in September 2003, causing heavy damage, including to wind turbines.
Enercon’s E82 unit, knowcked down during Typhoon Jebi, was installed in 2010 following the strengthening of the wind turbine construction assessment.
The JWPA added that an anemometer near the site recorded all-time high speeds and that it was assumed that the turbine was hit by "gusts exceeding its design limit".
An earthquake measuring 6.7 on the Richter scale also struck the northern island of Hokkaido at in the early morning of 6 September 2018.
It forced power outage at large-scale fossil fuel power plants and a grid failure, causing a blackout across the island.
Initial reports suggest the earthquake has not damaged wind turbines, but, following the grid failure, they were not delivering power, the JWPA added. However, most sites were reconnected to the grid just before noon on 11 September.
At least nine people have been killed during the earthquake, according to the Japan Times.