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2017/08/05 03:17
Kenji Kaneko, Nikkei BP Intelligence Group, CleanTech Institute
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Solar plant set up on former waste disposal site

Hills and highlands spread across Oishi District of Otsu City to the south of Lake Biwa, Shiga Prefecture. The "Otsu Clean Center Waste Disposal Site" is located in the mountains of this area. Otsu City manages the site, which is filled with incinerated residue of general waste. As you go up a gently sloping hill in the disposal site, you will find solar panels orderly set up in the deepest area.

Kokusai Kogyo Co Ltd (Chiyoda-ku, Tokyo) of the Japan Asia Group started operating "Otsu SolarWay" in January 2016. A total of 3,792 solar panels with a total output of 948kW were arrayed across the site, which had been developed into four stages like terraced fields (Fig. 1). It generates electricity of an amount equivalent to the consumption of about 175 general households, and all generated power is sold to The Kansai Electric Power Co Inc.

Fig. 1: "Otsu Solar Way" built on a former disposal site (source: Kokusai Kogyo)

In fact, Otsu Clean Center had managed this site after covering with earth the filled land, which had originally been a final waste disposal site. A private solar power producer rented part of this waste disposal site.

Kyocera panels, TMEIC PV inverters

NEC Networks & System Integration Corp provided engineering, procurement and construction (EPC) services, setting up Kyocera Corp's polycrystalline silicon solar panels (250W/unit) on the 16,241m2 site. As for PV inverters, a product of Toshiba Mitsubishi-Electric Industrial Systems Corp (TMEIC) was adopted. JAG Energy Co Ltd of the Japan Asia Group operates and maintains the plant (Fig. 2).

Fig. 2: Kyocera panels and TMEIC PV inverters were adopted, while JAG Energy operates and maintains the plant. (source: Nikkei BP)

The number of such "solar plants on former disposal sites" is gradually increasing partly because the Ministry of the Environment is promoting their construction. In many cases, a municipality rents a former disposal site to a private solar power producer and sets up a solar system on it. The Japan Asia Group, in particular, is one of the power producers that boast the most such cases (See related article).

Former final waste disposal sites generally appear to be idle land at first glance, but their maintenance continues even after the landfill has been completed. The tubes to release gas generated as a result of decomposing organic waste and the drainage of rainwater that penetrated the land are kept for a certain period. When designing and constructing a "solar plant of a former disposal site," consideration needs to be paid to such facilities.