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Solar Plant Designed With Consideration for Residential Areas (page 2)

Green solar power plant on former factory site

2014/01/12 15:06
Shinichi Kato, Nikkei BP CleanTech Institute
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To maximize amount of power generation while maintaining vegetation

What characterizes this mega-solar power plant is the request delivered by Tsurugashima City prior to the actual construction. The request was to leave to a certain degree the plants and trees as seen in the former Saitama Factory.

It was not easy to satisfy this request because the amount of power generation would lower should trees be standing around the solar panels and shade the panels depending on the season and time of day. What made it more difficult were weeds on the ground. In general, mega-solar power plants are designed to keep weeds from growing so that the amount of power generation would not decrease due to weeds covering the solar panels.

To prevent the amount of power generation from lowering as much as possible while satisfying the request by Tsurugashima City, Yomeishu Seizo adopted two measures. One was to keep the trees planted along the site's perimeter from shading the solar panels, and the other was to prevent the weeds from growing over the solar panels while still covering the ground.

First, the white oaks planted along the perimeter of the former Saitama Factory were left as they were. The white oaks, which can grow quite tall, had grown higher than 10m. But they were all cut shorter to about 6m. New white oaks were planted in the areas where there was no tree along the perimeter (Fig. 2).

On the other hand, the cherry trees along the perimeter were all cut down. It was because these trees, despite being beautiful when blooming in spring, could cause problems to the neighboring residential areas when their leaves fall in autumn. As white oaks are evergreen, their leaves seldom fall.

Also, the layout of the solar panels was specially arranged. The panels were positioned about 12-20m away from the perimeter so the white oaks would not shade any panels. As a result, as long as the white oaks are 7m or shorter, they do not shade the solar panels even at 15:00 on the winter solstice, the day in the year in which the shadows get the longest (Fig. 3).

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