7.55MW Floating Solar Plant Damaged by Typhoon

French firm's mounting system turned over by winds, waves

2016/09/06 20:56
Kenji Kaneko, Nikkei BP CleanTech Institute
The west "rim" was turned over by strong winds and high waves. (source: Nikkei BP)
Most of the two rows on the west side was turned over. (source: Nikkei BP)
The two rows were placed on the adjacent two rows of solar panels. (source: Nikkei BP)
The rim with solar panels sticking out from the floats was turned over. (source: Nikkei BP)

One of the largest-scale floating solar power plants in Japan was damaged by strong winds and high waves that seemed to be caused by Typhoon No 9 Aug 22, 2016.

The mega (large-scale) solar power plant, "Kawajima Taiyo-to-Shizen-no-Megumi Solar Park," has an output of about 7.55MW and is located in Kawajima-machi (town), Saitama Prefecture, Japan.

Among mounting systems floating on the water surface and solar panels mounted on them, 152 panels (41.8kW in total) were damaged by surrounding floating mounting systems that were lifted up, etc.

The mega solar plant started operations Oct 26, 2015, by using the water surface of the "Umenoki Furugori Water Reservoir," an agricultural reservoir being maintained by a land improvement district of Kawajima-machi. The surface area of the reservoir is about 130,000m2, and 27,456 solar panels were fixed on the floating mounting systems.

The solar panel is a monocrystalline silicon type (275W) manufactured by Yingli Green Energy Holding Co Ltd, and the floating mounting system is a product of France-based Ciel&Terre International.

According to data of Japan Meteorological Agency, a maximum instantaneous wind speed higher than 20m was recorded in the southern area of Saitama Prefecture, where Kawajima-machi is located, from 15:00 to 16:00 on August 22 due to Typhoon No 9. Because strong winds came from the northwest, west-northwest and west, the west side of the floating solar power plant was probably lifted up by strong winds and high waves, flipping over the mounting systems.

Two rows of the west "rim" were turned over and placed on the adjacent two rows of solar panels, damaging a wide area.

Ciel&Terre's floating mounting systems are made of high density polyethylene, which is resistant to ultraviolet light and corrosion. At a solar power plant in France, its mounting system has been used for more than five years. And the company's products reportedly feature a high strength design and connection technology to withstand even typhoons. And they are being employed for an increasing number of floating mega solar plants in Japan one after the other.

The power producer for Kawajima Taiyo-to-Shizen-no-Megumi Solar Park is Kawajima Taiyo-to-Shizen-no-Megumi Solar Park LLC, an SPC (special purpose company) established by Smart Energy Co Ltd (Chuo-ku, Tokyo). It was invested in by Smart Energy Service Co Ltd (Saitama City, Saitama Prefecture), which provides consulting services for energy saving, Tojogas Corp (Shiki City, Saitama Prefecture) and Daitogas Inc (Miyoshi-machi, Iruma-gun, Saitama Prefecture) in addition to Smart Energy.

In regard to the causes of the damage, Smart Energy made a comment saying, "The water level became more than 1m higher than the design standard of the floating mounting system manufacturer, and the systems violently moved upward and downward. At the same time, side winds hit the systems, creating a situation equivalent to that of a ship being turned over."

When Ciel&Terre's floating mounting systems are used, solar panels are usually not mounted on the peripheral area, where there are only connected floats. This time, such "empty" floats were not connected to the rim of the floating mounting systems turned over by strong winds, and solar panels were sticking out from the mounting systems. Some pointed out that the rear sides of the panels were easily hit by winds because of that.