Industry, academia developing next solar technologies

As Japan looks increasingly likely to shed its dependence on nuclear power, the focus is shifting to alternative energy projects such as a cutting-edge solar thermal collector at the University of Miyazaki's Kibana Campus in Miyazaki Prefecture.

The university's faculty of engineering has completed the solar collector, which it is calling the "largest in Japan and the world's most state of the art."

The university is attempting to create new technologies with the aim of building a major solar energy research center, which will take advantage of the fact that Miyazaki Prefecture ranks among the sunniest prefectures in Japan.

The campus' solar power equipment now in operation includes four types of large installations, each built by a different company. Combined, they have a maximum power output of 179 kilowatts, enough to supply roughly 3 percent of the campus' electricity needs. The university is collaborating with industry in joint research that enjoys the advantage of being able to compare the performance of each system under identical conditions.

A new "beam down" solar thermal collector was completed on Aug. 6 in one corner of the campus' south side.

The 880 mirrors, each with a diameter of 50 centimeters, track the sun automatically. The 16-meter-tall central tower gathers sunlight in a 4.3-meter-wide reflector that looks like an upside-down bowl because of the way it is placed. The light is then irradiated ("beamed down") toward the focal point below, where it accumulates energy in the form of heat a thousand times greater than that produced by direct sunlight.

Local companies based in Miyazaki Prefecture built and assembled the mirrors and tower with technology patented by Mitaka Kohki Co., an optical equipment maker located in Mitaka, western Tokyo.

While conventional designs that can reach a temperature of up to 600 degrees Celsius have been commercialized for solar thermal power generation in the United States and elsewhere, Mitaka Kohki President Katsushige Nakamura proudly states that "the beam down design can easily produce a temperature of 1,400 degrees."

This is hot enough to break down water and create hydrogen, which can then be used to power fuel cells. But conventional furnaces typically burn oil and other fossil fuels to maintain such a high temperature during this process. Niigata University, which possesses technology for producing hydrogen through solar collection, is spearheading joint research between industry and academia in this field.

Some hope that the new solar collectors can be converted into "solar furnaces" that use the sun as a heat source. If successful, they could provide a steady supply of cheap, raw silicon for solar cells, a resource for which Japan is now entirely dependent on imports.

Last year, associate professor Kensuke Nishioka, an expert on semiconductor engineering, succeeded in producing highly pure silica with volcanic soil from a deposit in southern Kyushu. When oxygen is removed from silica, it becomes silicon. Nishioka says that if a solar furnace can provide the temperature of 1,800 degrees required to perform this process, then it would bring the price of solar cells down to a third of their current level.

He says that the current method of using an electric furnace to heat the silica means that "half the price of silicon comes from the cost of electricity." This is why China, a country that produces highly pure silica from natural deposits and where electricity is cheap, has conquered the global market for solar cells.

Sand grains contain even more silicon than volcanic soil. As Nishioka describes his vision, "the deserts of Africa will become an inexhaustible silicon factory if we can utilize the large amount of sunlight received there." To Nakamura, the business potential is significant.

"Small to midsize enterprises will be able to enter the solar power sector that large firms with financial muscle have monopolized," he says.

These projects are part of the Photovoltaic Generation Project, a collaboration between industry and academia that the University of Miyazaki started in the 2009 academic year. The interdisciplinary scope of the project, which covers everything from materials development to practical applications, invites people from companies to act as lecturers and is implementing the first curriculum in Japan specializing in solar power. Meanwhile, the project is playing a role in training the people who will work in related industries.

The university's extension courses range from advanced lectures for professionals and researchers to a lab for children. One of the elementary students who attended this school year's fourth beginner's course on Aug. 10 said, "I think it's cool how they can send solar cells up above the clouds and generate power in space." The student was very much interested in the "near-future technologies" that Nishioka presented.

Solar energy-related industries continue to grow rapidly as the foundation for the market broadens. Associate professor Kenji Yoshino, the project's leader, is upbeat.

"Right now the Chinese are killing us, but the demand for Japanese technology is high," Yoshino says. "Creating interdisciplinary organizations is an urgent matter for turning the situation around. (We plan to) be proactive in showing off our strengths and making the University of Miyazaki into a center of research (in this field)."