The government has begun discussions on Japan's long-term energy mix, with the likely focus on how much nuclear power should account for the nation's electricity supply — a question that has been politically skirted since the 2011 meltdowns at Tokyo Electric Power Co.'s Fukushima No. 1 nuclear power plant. But the government's scenario reported by the media even before discussions at a panel of experts at the trade and industry ministry began last week raises doubts over Prime Minister Shinzo Abe's repeated pledge that his administration would seek to reduce Japan's dependency on nuclear power as much as possible.

At issue will be the nation's energy mix by 2030. The panel at the Ministry of Economy, Trade and Industry, led by former Komatsu Ltd. Chairman Masahiro Sakane, reportedly plans to reach a conclusion by summer. By setting the future shape of the energy supply components, the government hopes to set a target for reducing Japan's emissions of global warming gases in time for the international talks on long-term cuts to emissions with a view to reaching an agreement by yearend.

Just before the 2011 Fukushima disaster, nuclear power accounted for 28.6 percent of the nation's electricity supply, while thermal power plants supplied 61.7 percent of the total, hydro power 8.5 percent and other renewable sources a mere 1.1 percent.