Japanese mobile telecom company Softbank and trading company Mitsui & Co have announced that the two companies will partner in the construction of two utility-scale solar plants in Japan.

Japanese news outlets reported that SB Energy, the division of the Softbank Group responsible for renewable energy generation, and Mitsui & Co, one of Japan's largest trading companies, will build a total of 42MW capacity - one plant of 22.4MW and another of 19.6MW.

The two new plants will be built on the island of Kyushu, to the south of the main Japanese island Honshu. Several large scale projects have been built on Kyushu, including Japan’s largest PV plant to date, a 70MW installation in Kagoshima which was inaugurated recently.

Both of the new power stations, the 22.4MW Softbank Kumamoto Arao Solar Park in Kumamoto prefecture and the 19.6MW Softbank Omuta Miike Port Solar Park, will be built on land owned by fossil fuel company Nippon Coke & Engineering. Kumamoto Arao Solar Park will have an annual output of around 21,896MWh per year, while Omuta Miike Port Solar Park will have an estimated output of 20,050MWh per year.

The plants will be jointly owned and operated by Mitsu & Co and SB Energy. The two companies have collaborated previously on several renewable energy projects and have formed a special purpose company (SPC) for the newly announced plants. The SPC is currently headquartered in Tokyo but is expected to be moved to offices local to the parks.

Softbank chief executive officer Masayoshi Son, one of Japan’s richest men, estimated to be worth around US$13 billion, is a vocal advocate for renewable energy.

The two newly announced solar power stations will begin construction in January 2014, expected to finish by the end of the 2014 Japanese financial year in March 2015. In addition to the two new plants, Mitsui & Co and SB Energy began construction in October on a 111MW PV plant in Hokkaido, northern Japan.