The Japanese archipelago was stricken by a series of serious natural disasters this summer, including the repeated torrential rains and typhoons that hit western Japan, as well as a major earthquake in Hokkaido. Disasters at solar power plants and wind power plants were also reported by the mass media and SNS.

The Ministry of Economy, Trade and Industry (METI) announced on Aug 28, 2018, that 15 solar power plants in six prefectures, namely Hyogo, Hiroshima, Okayama, Yamaguchi, Shimane and Ehime prefectures, were damaged by the torrential rains in western Japan (known as the "Torrential rains in July 2018"), in respect to plants larger than 50kW, which are required to submit reports.

It is estimated, however, that most of the plants affected by the disaster were low-voltage solar power plants for business use between 10kW and 50kW, and the overall picture of the damage, including damage to equipment mounted on houses, cannot be fully grasped.

In this troubleshooting report, we are covering solar power and wind power plants damaged by the western Japan torrential rains in early July and typhoons No. 21 and No. 22 that hit Japan in late August and early September, as well as the impact of the Hokkaido Eastern Iburi Earthquake on the renewable energy generation business.

Contacts Shinkansen line fence

The Shinkansen line was stopped due to the collapse of solar power generation equipment caused by the torrential rains in western Japan.

On the night of July 5, 2018, a slope beside the railway tracks collapsed near the exit of a tunnel along the Sanyo Shinkansen Line in Suma-ku, Kobe City, Hyogo Prefecture. The collapse occurred between Shin-Kobe Station and Nishi-Akashi Station. According to an announcement by Kobe City, solar power equipment that was installed on the slope also collapsed (Fig.1).

Fig. 1: The solar power equipment in Suma-ku, Kobe City, collapsed due to the torrential rains. (source: Kobe City)

An entire array (a unit for fixing solar panels on a mounting system) of six panels arranged in latitudinal direction on the slope collapsed. The solar power plant is believed to be a low-voltage solar power plant for business connected to a low-voltage transmission line. There are fences that separate the Shinkansen railway tracks from the external areas on the land adjacent to the east of the array and at the bottom of the slope. Part of the array that collapsed hit the fence, bending it significantly.

Although the solar power generation equipment did not break through the fence or protrude into the railway track area, West Japan Railway Company (JR West) determined that the equipment could reach the area near the railway tracks or it could contact the overhead lines if the collapse worsened, and the operation of the Sanyo Shinkansen Line was stopped temporarily.

When we later visited the site, the slope was repaired and the solar power generation equipment had been removed. The slope was fairly steep (Fig.2).

Fig. 2: The site in Suma-ku, Kobe City, from which the damaged equipment was removed (picture: Nikkei BP)

Drain water flows like a stream below the bottom of the slope and the top side of the slope is adjacent to a residential area. A fence made of pipes stood between the residential area and the slope and color cones had been placed along the fence to prevent access to the slope. They are new and appear to have been installed after the removal of the solar power generation equipment.

Resin parts for water collection and drainage could be on the slope and a fence made from layers of wooden boards was installed near the fence of the Shinkansen Line. They are also new and appear to have been installed after the collapse.

Responding to the serious accident of the collapse of the solar power generation system, which stopped the operation of the Shinkansen Line and had a significant influence on society at large, Kobe City announced its plan to establish an ordinance that specifies regulations on the installation of ground-based solar power generation equipment and requirements on reporting the management situation, aiming to prevent accidents of this kind. The ordinance will be applied to power generation equipment with an output of 10kW or more.