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Solar Panels Arrayed in Accordance With Slopes Using New Construction Method

Concrete piles cut for adjustment, wireless string monitoring adopted

2016/03/03 23:11
Shinichi Kato, Nikkei BP CleanTech Institute
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The "Exeo Matsue Solar Farm" is a mega- (large-scale) solar power plant with an output of about 2.3MW in Matsue City, Shimane Prefecture (Fig. 1). It is located next to the village forest to the east of JR Matsue Station.

Fig. 1: "Exeo Matsue Solar Farm" is a 2.3MW-output mega-solar power plant next to the village forest to the east of JR Matsue Station. (source: Kyowa Exeo)

Kyowa Exeo Corp, which is known as a communication- and telecom-related infrastructure company, constructed the plant. The Exeo Matsue Solar Farm rented about 25,000m2 of land in Asakumicho, Matsue City, as a mega-solar site and arrayed 8,784 solar panels there. Facing south, the sloping site is suited for solar power generation.

Its annual power generation is expected to total roughly 2,540,000kWh, which is equivalent to the consumption of about 450 general households. The generated power is sold at ¥36/kWh (excluding tax).

Each string is comprised of 24 panels connected to form a 1,000V direct-current (DC) circuit. When divided into either two bottom rows or two top rows, however, the number of panels that form a string in an alley went below 24 in some areas. In those cases, a string was structured by connecting panels of an adjoining array.

Having leveraged the existing undulations of the site when setting up the panels, the angle and height vary by array, as does the shadow over the panels. The plant, therefore, used a 3D CAD (three-dimensional data-based design tool) to design the plant so the impact of shadows over each array would be even.

As a result of these efforts, the overload ratio of solar panel capacity was raised to about 2.32MW against the grid connection capacity of 1.99MW. The plant adopted 8,784 units of Sharp Corp's single crystal silicon-type 265W-output product and two 665kW-output and one 660kW-output PV inverters manufactured by Toshiba Mitsubishi-Electric Industrial Systems Corp (TMEIC) (Fig. 2).

Fig. 2: TMEIC's DC 1,000V-mode PV inverters (665kW x 2, 660kW x 1) were adopted. (source: Nikkei BP)