Construction consultant New Nippon Consultants Co Ltd (NiX, Toyama City) completed the mega- (large-scale) solar power plant "NiX Yatsuo Solar Power" with an output of 1,260kW on a municipal property in Kamisasahara, Yatsuomachi, Toyama City, Toyama Prefecture, in October 2014 (Fig. 1).
Needs to overcome 'triple handicap' unique to Hokuriku region
Ahead of constructing the "NiX Yatsuo Solar Power," NiX had to overcome three major obstacles that lower profitability in the solar power generation business (Fig. 2).
First was the Hokuriku region's unique sunshine condition, meaning the amount of sunlight is less than in other general mega-solar power plant sites in Japan. Compared with mega-solar power plants on the Pacific Ocean side of the country, for example, power sales tend to be smaller in Hokuriku.
Second was its location in a snowy area. Capital investment increases due to designs that can withstand the weight of snow (Fig. 3). Moreover, snow on the panels freezes and the snow that falls under the panels tends to stay without melting due to the low temperature in the area. Power sales decline during the time when snow covers the solar panels.
Third was the site, which was not a large connected piece of land but consisted of small scattered pieces of land. The site was not only divided into a north and south block but was also separated by a road. And many of the pieces were not rectangular shaped.
It was difficult to efficiently array the solar panels. Also, it resulted in extended lengths of transmission cables and fences around the site, which causes the capital investment to rise (Fig. 4).
'Model to combat snow-covered mountains' realized
NiX could only overcome the "triple handicap" of low sunshine, snow cover and a scattered site by maximizing the power generation amount through devising the panel distribution, lowering capital investment through boosting efficiency of the overall solar power generation system and adopting low-cost measures against snow cover.
Maximizing panel numbers, adding rented sites
First, NiX optimized the solar panel distribution and maximized the power generation amount. Moreover, it increased the number of installed solar panels, renting peripheral land around the plant site, which was not included in the initial plan, from Toyama City.
NiX adopted solar panels manufactured by Next Energy & Resources Co Ltd (Komagane City, Nagano Prefecture). A total of 4,800 295W polycrystalline silicon panels were arrayed.
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