Kakegawa City, Shizuoka Prefecture, faces the Sea of Enshu and extends for a long way from north to south, with the New Tomei Expressway, the Tokaido Shinkansen Line and the Tomei Expressway, and Route 150 crossing the area in the north, middle and south, respectively. Despite the tea fields seen through the windows of the Shinkansen (bullet train) that give people the impression the city is a tea-producing area, there are a lot of rice paddies and greenhouses growing produce such as strawberries and melons in the south.

67,000 solar panels on both banks of a river

As you drive across the Higashi-oya River on Route 150 and go by greenhouses and vegetable fields after making a turn to the seaside, solar panels that are arrayed along the coastal levee toward the horizon will come into view. This is the "Kakegawa Obuchi Okinosu Extra-high-voltage Solar Power Plant," a mega- (large-scale) solar power plant with an output of 17.95MW (Fig. 1).

Fig. 1: Kakegawa Obuchi Okinosu Extra-high-voltage Solar Power Plant (source: Nikkei BP)

Asahi Corp (Hamamatsu City, Shizuoka Prefecture) of the Asahi Group, a construction company and a real estate developer based in Hamamatsu City, constructed and operates the plant.

The plant was set up in the coastal area in Okinosu District, formerly Osukacho, which once prospered as a castle town surrounding Yokosuka Castle. On both banks of the Higashi-oya River, solar panels were arrayed on a long, narrow site that extends about 1.5km along the coast. The site is about 13ha on the right bank and about 4ha on the left bank, and was collectively rented from 150 individual landowners.

Set up on the right bank were 51,375 solar panels, whereas 16,380 panels were set up on the left bank. Annual power generation is expected to amount to 19,750,000kWh, which is equivalent to the consumption of about 5,400 general households. Given that there are roughly 3,900 households in Osuga District, this plant's output is estimated to outperform the local demand for electricity.

A total of 67,755 polycrystalline silicon solar panels (265W/unit) of Canadian Solar Japan KK and 30 500W PV inverters of Toshiba Mitsubishi-Electric Industrial Systems Corp (TMEIC) were installed.