Seafront Solar Plant Withstands Wind, Wave, Ground Subsidence
'Overload' helps PV inverters work at maximum efficiency around noon
Fig. 7: In the outer rows, the number of piles to be built like a curb was increased from 2 to 3, as at the bottom left. And transverse piles were added, as at the bottom right, to make the foundations better endure the stronger wind compared with other rows. (source: Nikkei BP)
Mitsui Engineering & Shipbuilding (MES) Co Ltd's Oita Works boasts a huge site of about 1.7km2 and started operation in 1981 as a plant where large structures such as bridges and cranes are manufactured. Throughout the site are a number of steel components as large as 10m or longer and huge dock cranes being assembled. Their massiveness and impact are overwhelming.
"Mitsui Engineering & Shipbuilding/Mitsui Fudosan Oita Solar Power Plant" is located in the corner of this vast plant (Fig. 1). The 14MW output mega (large-scale) solar power plant started selling electricity to Kyushu Electric Power Co Inc Dec 1, 2013. MES and Mitsui Fudosan Co Ltd are running the plant as a joint business.
Golf course, mega-solar power plant instead of huge shipbuilding yard
The location of MES's Oita Works (Fig. 2) is an area that Oita Prefecture established as an industrial site, where the operations of leading companies in the steel, automobile, chemical and other heavy industries are concentrated.
MES, which purchased the vast site from Oita Prefecture, initially planned to build an enormous shipbuilding yard that would be Japan's largest. However, hit by the shipbuilding recession following the Oil Shock, the company built a plant for producing bridges and other large steel products, postponing the construction of the shipbuilding yard.
As large structures are still much smaller than huge cargo ships, the area needed for manufacturing shrank to only one-third the acquired site, with the remaining west and north sides left idle. MES then opened the "Hiyoshibaru Country Club" golf course on the west side in 1990.
What made the company start considering the construction of a mega-solar power plant on the north side of the land followed a proposal by Mitsui Fudosan in the fall of 2011, when the implementation of the feed-in tariff (FIT) scheme for reusable energy was being discussed. The proposal was approved by the board of directors in August 2012 after the details of the FIT program were announced in June that year.
'Joint venture' with Mitsui Fudosan rather than SPC
Many of the mega-solar power plants with an output of 10MW or more establish a special purpose company (SPC) and structure project financing funded by financial institutions.
However, "Mitsui Engineering & Shipbuilding/Mitsui Fudosan Oita Solar Power Plant" established the joint venture "Mitsui Engineering & Shipbuilding/Mitsui Fudosan Joint Venture," instead of using project financing, with MES and Mitsui Fudosan providing business funding of about ¥4 billion (approx US$39.2 million), contributing 51% and 49%, respectively. The joint venture rents the mega-solar power plant site from MES.
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