Japanese Shell subsidiary plans solar-panel plant

Corrected July 9 at 6 p.m. PDT: This blog initially stated that CIS reached an efficiency of 20 percent. The studies showing that efficiency used a higher light concentration than the studies of CIGS efficiency. When comparing the two, CIS has a lower efficiency of around 15 percent.

Royal Dutch Shell subsidiary Showa Shell Sekiyu, Japan's fifth-largest oil refiner, plans to invest 100 billion yen, or about $938 million, in a solar-panel megaplant, according to AFP.

The planned factory will produce panels with the cumulative annual capacity to produce 1 gigawatt of power, equivalent to that of a small nuclear-power reactor.

The news breaks a month after Japanese Prime Minister Yasuo Fukuda called for a tenfold increase in the country's use of solar power by 2020. The government is considering subsidies to boost the industry.

Showa came into the solar-power business last year, with its first 20-megawatt-capacity photovoltaic plant in the southern city of Miyazaki. In August, it announced plans to build a second factory, with a capacity to produce 60 megawatts.

The company produces its thin-film photovoltaics with copper, indium, and selenium (CIS). This differs from the combination of copper, indium, gallium, and selenium (CIGS) that companies such as Miasole, HelioVolt, Nanosolar, and Global Solar are using.

In 2005, CIS had reached a maximum efficiency in converting solar light to electricity of 15 percent, according to the U.S. Department of Energy's National Renewable Energy Laboratory, NREL (PDF). That is less than the 19.9 percentage mark that CIGS cells achieved in March by researchers at the U.S. Department of Energy's National Renewable Energy Laboratory. The reason Gallium is added into the CIS cell (to make it a CIGS cell) is to raise the band gap of the material. This enables the material to more efficiently absorb the solar spectrum and in turn increase the efficiency of the cell. But it also makes CIGS more complicated--and potentially more expensive--to manufacture than CIS thin film.

The location of the new plant remains undisclosed, but rumors say the company is considering areas of Japan, Europe, and the Middle East. Equally unknown is the financial source for the project.