The "Shoken Ishibe Solar Power Plant," a mega- (large-scale) solar power plant with an output of about 1.81MW, is located in an asphalt/concrete plant site in Ishibekita, Konan City, Shiga Prefecture, Japan (Fig. 1).

Fig. 1: About 1.81MW-output Shoken Ishibe Solar Power Plant in asphalt/concrete plant site (source: Shoken)

As indicated by its name, the power producer is Shoken Co Ltd (Otsu City), a general contractor focusing on local civil engineering. Shoken also developed and operates the "Shoken Kashiwabara Solar Power Plant" with an output of about 2.45MW in neighboring Maibara City, Shiga Prefecture. Shoken's two mega-solar sites are both entirely asphalted, a characteristic that is rarely seen at other general solar power plants (Fig. 2).

Most other asphalted mega-solar power plants in Japan had already been asphalted and used as is when they were converted into solar plants. Asphalted ground, if used as is, is not only beneficial in terms of construction and operation/management, but is also cost-effective. However, asphalting is rarely adopted when constructing a new mega-solar plant, as it increases the initial cost and lowers the return on investment.

Shoken newly asphalted the sites when setting up the solar power generation facilities. Engaged in asphalting as its mainstay business, Shoken knows well how to keep costs relatively low through effective construction. According to Shoken, taking operation and maintenance (O&M) work into consideration, asphalt is highly likely to boost business performance over a solar plant's total project period, and Shoken can implement measures against any asphalting-related risks. It can be said that the company made the best use of the knowledge of its mainstay business.

It has been about six years since the mega-solar plant in Konan City began operation in February 2013. Meanwhile, in two months, it will be five years since the Maibara site began operation in April 2014 (See related article).