Yoshihiko Noda is Japan’s sixth prime minister in five years, replacing Naoto Kan after his resignation. Credit: H. Yamaguchi/Corbis

Yoshihiko Noda, Japan's new prime minister, has a daunting in-tray to deal with: a faltering economy, a huge reconstruction effort following the devastating earthquake and tsunami in March, and an ongoing nuclear emergency at the Fukushima Daiichi power plant. Elected on 29 August after Naoto Kan's resignation last week as leader of the ruling Democratic Party of Japan, Noda must also contend with the threat of a complete vacuum where the country's energy policy should be.

After the Fukushima disaster, Kan vowed to "leave nuclear energy behind", but made no clear plans to fill the energy gap. And neither Noda nor the other leadership contenders articulated a clear position on energy during the brief election campaign. When pressed on the issue, they steered clear of strong statements about the future of nuclear power or how they would keep the lights on in its absence. "We have no energy policy," says Tatsuo Oyama, who studies investment in power utilities at the National Graduate Institute for Policy Studies in Tokyo. "It's a serious issue that Noda has to deal with."

Last year, Japan committed to constructing 14 new reactors so that nuclear power would provide half of the country's electricity by 2030. But after the accident at Fukushima, public mistrust of the technology prompted Kan to ditch the plan. He also ordered existing reactors to be taken offline for a series of stress tests, in addition to normal inspections. All but one of the country's 54 existing reactors are set to be shut down by May 2012, removing a quarter of Japan's power capacity. Restarting them would require approval from local governments, which they may be reluctant to grant.

Kan had promised that renewables and efficiency measures would make up the shortfall, but did not explicitly say how. "He made a change but he did it without debate and without a road map," says Tsutomo Toichi, an energy specialist at the Japanese Institute of Energy Economics in Tokyo. "It was very abrupt."

The short-term consequence has been a jump in the use of fossil fuels, including an estimated 20% increase in imports of expensive liquefied natural gas. Toichi says that there could be a 20% increase in the cost of producing electricity in 2012 if nuclear reactors are shut down as expected, probably leading to higher rates for consumers. This week, the Tokyo Electric Power Company announced that it is considering a 10% hike in next year's electricity rate. Citizens' willingness to economize has trimmed power demand in Japan, but Oyama believes that the sagging economy has also reduced electricity consumption. Hiromasa Yonekura — chairman of Sumitomo Chemical, headquartered in Tokyo and Osaka, and head of the powerful Japan Business Federation (Keidanren) — has repeatedly warned that high prices could force companies to move operations overseas.

There is now a broad consensus that we need to reduce our reliance on nuclear power. ,

To prevent this, Toichi says that the new government must get the nuclear plants back online as soon as possible. Despite public opposition, Noda has hinted that nuclear will continue to make up part of Japan's energy mix, and industry minister Banri Kaieda announced for the first time this week that he expects some reactors to restart this year.

That would be a step in the wrong direction, says Tetsunari Iida, director of the Tokyo-based Institute for Sustainable Energy Policies, who wants the country to seize the opportunity to invest in renewable energy.

On 12 September, Iida will launch the Japan Renewable Energy Foundation, which is backed by ¥1 billion (US$13 million) from Japan's richest man, telecoms mogul Masayoshi Son. The foundation will bring together some 100 experts from around the world to analyse obstacles to implementing renewable energy, and offer policy recommendations to the new government.

The foundation's cause did get a boost from Kan, who had agreed to step down only if Japan's parliament passed a bill to support clean energy. The bill, which passed on 26 August, will next year guarantee a minimum price for wind, solar and other renewable energies that will make them more attractive for suppliers to invest in.

Iida is confident that this will help to sustain the shift away from conventional power sources. He notes that, from 2008 to 2010, Japan's annual increase in solar-power capacity jumped from 230 megawatts to almost 1 gigawatt, giving the country a total capacity of 3.6 gigawatts. He believes that the renewables bill will make huge solar farms economically attractive for the first time. "I think next year we'll see a tenfold jump in solar and fivefold in wind," he predicts. Many say that this is unrealistic. "It's impossible within two years, and too ambitious within ten," says Toichi.

A bill on global warming could also boost renewables by preventing Japan from filling its energy gap with fossil fuels. But the bill's prospects are dim, even though its aim — a legally binding target to reduce greenhouse-gas emissions to 25% below 1990 levels — was once a cornerstone of the Democratic Party's manifesto. "Because of the reduction in our reliance on nuclear power, it will be very difficult" to hit that target, says Toichi.

Japan's parliament has so far declined to consider the bill, and political support for it is waning rapidly. "The new majority position [within the Democratic Party] is to get rid of the 25% target," says Iida.

Yet despite the uncertainties that now cloud Japan's future, Kan's administration did at least deliver one clear achievement on energy policy, says Iida. "There is now a broad consensus that we need to reduce our reliance on nuclear power. That is the atmosphere now."