Japan goes for the sun

Government pushes to regain national lead in solar-energy research.

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Tens of thousands of Japanese homes and businesses are preparing to put new solar panels on their roofs, spurred by a subsidy plan going into effect this month. It is a step towards regaining Japan's once-dominant position in solar energy, something that has become a matter of pride for the country's policy-makers.

But the government knows it cannot count on citizens to continue backing solar energy out of civic pride and eco-mindedness alone, so it is now spending ¥30 billion (US$300 million) of state money annually on subsidies and research and development on the technology.

In 1999 Japan led the world in solar-cell production, a position it maintained for several years. In 2005, solar cells produced by Japan accounted for 45% of the world's capacity, according to figures from the country's industry ministry. By 2007, however, the figure was only 24.6%, barely ahead of China's 22.0%.

Each year from the late 1990s on, Japan also installed more capacity for producing energy from solar cells than any other country, but was surpassed by Germany in 2005 and Spain in 2008. It more than doubled its total capacity between 2003 and 2007, but could not keep pace with Germany's ninefold increase over the same period. The German boom was fuelled by a 'feed-in' tariff which guarantees that solar-cell power plants and rooftop installations receive a high price for electricity that they feed back into the grid. By 2007, Germany had twice Japan's 1.92 gigawatts of installed capacity.

Japan knows how to do solar power at home. Credit: Y. NAKAO/REUTERS

Japan now wants to get back on top. Last July, the cabinet announced a low-carbon-economy action plan that called for the country to "regain its global leadership position in solar generation". It set out ambitious targets to increase its 1.4 gigawatts of solar power capacity in 2005 20-fold by 2020. The 2009 budget earmarks ¥10 billion for solar-photovoltaic energy research and development. Another ¥60 billion has been set aside for renewable energy subsidies, a third of which will go on solar cells.

The country's recently announced economic stimulus package also targets solar research and development as a major investment area, although specific numbers have not yet been determined (see Nature 458, 819; 2009).

The subsidy programme starting this month gives ¥70,000 per kilowatt to homes and businesses that install solar panels. So far it is proving popular, with 22,000 applications in its first two-and-a-half months.

Takashi Kawabata of the industry ministry's new and renewable energy division notes that Japan is unusual in having so much of its capacity — 1.55 million kilowatt-hours, or 80% — in homes and businesses. In Germany, only 40% of the country's capacity is found in these places; instead, power companies have found it profitable to invest because of the feed-in tariffs. "Germans do it because it is profitable," Kawabata says, "but there's no profit for the Japanese." To explain his fellow-citizens' motivation for installing the technology, he cites the well-known Japanese word yasegaman, which means 'endure for the sake of pride'.

“Germans do it because it is profitable, but there's no profit for the Japanese. ”

Nevertheless, Japan is debating a feed-in tariff of its own, which could come into effect in 2010 and would allow homes and businesses with solar panels to sell electricity back to the grid at twice the going rate. Many worry, however, that it would force electricity prices up overall. In Japan, the cost of producing a kilowatt-hour of electricity using solar cells is twice that charged to consumers.

The government aims to cut that cost in half within five years. The New Energy and Industrial Technology Development Organization, which distributes research money for the industry ministry, has been leading an eight-year field test to prove the value of large-scale solar panel installations. It is spending roughly ¥6.3 billion per year from 2007 to 2014 on this project, and about another ¥3.7 billion for various others aimed at raising solar-cell efficiency, making manufacturing processes cheaper and finding ways to use cheaper materials.

In one of these projects, some 30 university groups and companies have banded together for solar-cell research. Mitsubishi Electric, for example, has made polycrystalline solar cells that convert 18.8% of solar energy to electricity, compared with the 15–16% achieved by most on the market now. Sanyo's improved single-crystal cell has 22.3% efficiency — the world's best, according to project leader Masafumi Yamaguchi, a semiconductor materials scientist at the Toyota Technological Institute in Nagoya.

Yamaguchi is also the research adviser for a new programme funded by the Japan Science and Technology Agency. With a hefty ¥8 billion over seven years, 12 teams of scientists will try to find new materials to make solar cells cheaper.

Yamaguchi says Japan needs to pursue this course because of the pressure from cheap producers, especially in China. "It's the only way to compete," he says.

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Cyranoski, D. Japan goes for the sun. Nature 458, 1084–1085 (2009). https://doi.org/10.1038/4581084a

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