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1.7MW Solar Plant Overcomes Snow Cover, Frost Heave in Aomori (page 3)

Loss kept to minimum despite breakdown of PV inverter's cooling system

2019/04/02 23:56
Shinichi Kato, Nikkei BP Intelligence Group, CleanTech Labo
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Foundations free from 'frost heaving' effects

In addition, "frost heave," particular to the north of Japan, occurs around the mega-solar plant in Hachinohe City. Frost heave is a phenomenon where cold air freezes the ground and forms ice layers which become thick and raise the ground level, and it sometimes damages roads and building foundations.

Frost heave could also affect mounting system foundations at this solar plant and might cause mounting systems to distort or become loose after installation. Accordingly, concrete foundations measuring about 150cm underground and 50cm above ground were adopted, applying the same method used for setting up utility poles in this region (Fig. 5).

Fig. 5: Foundations built 150cm underground to counter effects of frost heave (source: Nikkei BP)

When I visited the site for an interview, the ground had been raised up by frost heave in many areas (Fig. 6). However, the construction method appeared to have produced the effect as designed, with the foundations and mounting systems not being affected by the phenomenon.

Fig. 6: Intact foundations despite raised ground in some areas (source: Nikkei BP)