Visit to Plant

Consideration Given to Historic Sites at Solar Plant in Former Castle

Operation delayed 2 yrs, efforts unique to remote island

2018/05/22 13:31
Shinichi Kato, Nikkei BP Intelligence Group, CleanTech Labo
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In March 2018, the "Kojindake Solar Power Plant," a mega- (large-scale) solar power plant with a solar panel capacity of about 5.3MW and a grid capacity of about 5MW, started operation on Fukuejima Island of the Goto Islands in Nagasaki Prefecture (Fig. 1). The Tamagawa Holdings Group developed and runs this plant.

Fig. 1: Connected with extra-high-voltage power transmission cables. Solar panel capacity is about 5.3MW while grid capacity is about 5MW. (source: Tamagawa Holdings)

Fukuejima is the largest among the Goto Islands and is located in the southwest of the islands in western Nagasaki Prefecture (Fig. 2). The island is known for having one of the most beautiful seas in Japan and a volcano, historic sites including those related to the envoys to the Tang Dynasty and former castle ruins, as well as Christian-related sites such as churches constructed from the end of the Edo Period after the migration and oppression of Christians.

Facing the East China Sea where the Black Tide runs from south to north, the island is blessed with rich seafood resources. Thanks to these attractions, the island has grown into a major tourist spot.

Fig. 2: Fukuejima Island is the largest among the Goto Islands. An aerial shot near the island's central area (top), Takahama Beach considered to be one of Japan's most beautiful beaches (middle), Osezaki Lighthouse overlooking the East China Sea (bottom left) and many small neighboring islands (bottom right) (source: Goto City, bottom right Nikkei BP)

At the moment, Japan is aiming to make the Goto Islands and its Christian-related heritage in Nagasaki registered as World Heritage sites by the United Nations Educational, Scientific and Cultural Organization (UNESCO). The registration decision will be made in July 2018.

Blessed with abundant sunshine, wind power and tides, there are many optimal places for renewable energy power generation in this region. Fukuejima has also adopted solar and small-scale wind power plants across the island (Fig. 3). In addition to those on the island, Toda Corp has started operating a floating power generator offshore, while the adoption of tidal power generation is also being considered.

Fig. 3: Suited for renewable energy-based power generation. The island has many solar (top left) and small-scale wind power plants (top right). Toda is running a floating wind farm offshore (bottom). On the island, many EVs run and EV charging stations have been constructed. (source: Nikkei BP)

As power transmission networks are usually small on remote islands, fluctuations in frequency and maintaining the supply-demand balance tend to become a challenge if a large-capacity mega-solar plant is connected to a grid. In this respect, the Goto Islands are connected with the grids on the Kyushu mainland via a submarine cable, with extra-high-voltage power transmission cables laid in Fukuejima Island.

Moreover, a steel tower for the extra-high-voltage cables is situated in the site of this mega-solar plant (Fig. 4). The site is actually surrounded by an optimum environment.

Fig. 4: A wonderful environment for grid connection with a steel tower for extra-high-voltage power transmission cables standing in the site (source: Nikkei BP)

On the other hand, in the case of a farming-type solar project with a total output of about 480MW planned for construction on Ukujima Island at the northernmost part of the Goto Islands (See related article), no extra-high-voltage power transmission cables have been laid in the island. Accordingly, a new extra-high-voltage power transmission cable is slated to be laid on the seabed up to Sasebo. Even among the Goto Islands, conditions for grid connection widely vary by island.