Visit to Plant

Large PV Inverters Set Up Above Reservoir at Floating Solar Plant in Kagawa

Reliable domestic products used, business performance ensured even at 18 yen/kWh

2019/12/11 16:49
Shinichi Kato, Nikkei BP Intelligence Group, CleanTech Labo
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A total of 9,408 solar panels are floating on the water surface of "Meimaike," a reservoir in Mikicho, Kita-gun, near Takamatsu City, Kagawa Prefecture, Japan (Fig. 1).

Fig. 1: Mega-solar plant on Meimaike Pond. Final adjustments before grid connection. Adjacent site to reservoir rented for use as office, material yard and for float connection (bottom right) (source: top and left in second row Sumitomo Mitsui Construction, others Nikkei BP)

This is the "Meimaike Floating Solar Power Plant," a floating mega- (large-scale) solar power plant with a solar panel capacity of about 2.822MW and a grid capacity of 1.99MW, which was developed by Sumitomo Mitsui Construction Co Ltd. Ahead of grid connection slated for January 2020, its construction has reached its final phase.

Kagawa Prefecture has many agricultural reservoirs like Hyogo and some other prefectures. In preparation for water shortages, many reservoirs have been constructed and primarily used for agriculture since old times. Meimaike is one of such agricultural reservoirs (Fig. 2).

Fig. 2: Reservoir has long history in rice paddy area (source: Nikkei BP)

There are also many other reservoirs near Meimaike. Sumitomo Mitsui Construction developed a floating mega-solar power plant on this reservoir because it had developed and runs a floating mega-solar power plant on "Hiragioike," a reservoir near Meimaike.

The floating mega-solar plant on Hiragioike has a power generation facility of an equivalent scale to the one on Meimaike, with a solar panel capacity of about 2.6MW and a grid capacity of 1.99MW. In November 2017, this plant started selling power to Shikoku Electric Power Co Inc at 32 yen/kWh (hereinafter excluding tax) based on the feed-in tariff (FIT) scheme (See related article).

During the development of this floating mega-solar plant on Hiragioike, an irrigation association approached Sumitomo Mitsui Construction regarding a floating solar power plant development on Meimaike, and that led to this project.

Despite the unit price of 18 yen/kWh at the floating solar plant on Meimaike, the company adopted solar panels of Mitsubishi Electric Corp and PV inverters manufactured by Toshiba Mitsubishi-Electric Industrial Systems Corp (TMEIC) just like at the floating solar plant on Hiragioike. These products have established a good reputation for their high performance and reliability, yet their cost advantages are not necessarily high.

As for floats to float solar panels on the water, Sumitomo Mitsui Construction adopted its own products as it did at the floating mega-solar plant on Hiragioike. Sumitomo Mitsui Construction said it is also "confident about their safety and reliability, but their cost is not low."

The company stressed that its policy was to run a power generation business more safely, with greater certainty and for a longer period of time, while giving comfort to the people concerned including the surrounding communities using such facilities focused on safety, reliability and performance.

Despite adopting such facilities and construction methods, the company can reportedly secure sufficient profit even at a unit price of 18 yen/kWh through the overall project's efforts to boost cost efficiency.