At the PV Japan 2014 conference in Tokyo, SunPower announced that it will supply Nangoku Corporation with PV modules for a 29 MW solar PV project. Nangoku plans to build the plant in a hilly region in Hioki, Kagoshima Prefecture, and says that the limited space was a factor in the choice of SunPower's high-efficiency modules.

Nangoku was scheduled to begin construction of the project in June 2014, and expects to complete the plant in August 2015. While solar is only one of the many businesses under the Nangoku name, the company has already built 12 MW of PV projects and is planning another 150-200 MW on the island of Kyushu, where Kagoshima Prefecture is located.

SunPower will supply its E20/327 PV modules, which are based on its Maxeon all-back contact cell technology and offer an average conversion efficiency of 20.1%. These modules also carry SunPower's combined 25-year combined product and power warranty, and the company says that they can provide 87% of their rated power at the end of 25 years.

While lower-efficiency multicrystalline silicon and cadmium telluride thin film modules are often chosen for large PV plants due to low costs per watt, SunPower continues to defy this trend by supplying utility-scale projects like this one with its high-efficiency monocrystalline silicon modules.

Japan has dramatically increased its share of imported PV modules since it began its feed-in tariff in July 2012, however SunPower's presence predates this policy. The company was one of the first Western suppliers to gain a foothold in this market, and has been supplying PV modules to Japan since 2010.

SunPower estimates that it has provided modules for a total of 150 MW of Japanese utility-scale projects to date, as well as another 250 MW into the residential and commercial market. In the fourth quarter of 2014, Japan made up 24% of SunPower's total sales.