TOKYO Japan's protracted nuclear safety crisis has begun to cast doubts over its pledge of ambitious carbon emissions cuts by the end of the decade, which will rely heavily on plans to boost nuclear power generation.
While Tokyo has not said explicitly that it would consider backing away from its 2020 target of reducing greenhouse gas emissions by 25 percent from 1990 levels, the scrapping of at least four reactors at the crippled Fukushima Daiichi plant and public wariness of new reactor projects could force a greater reliance on fossil fuels than policymakers had anticipated.
The first hints of a possible review of Tokyo's carbon cutting goals emerged in comments from bureaucrats and policymakers over the past few days.
"It is true that our reduction target will be affected significantly," Vice Environment Minister Hideki Minamikawa was quoted by the Yomiuri newspaper as telling reporters in Bangkok on Sunday.
"The target year and the size of the reduction will be up for review."
Senior officials from the ruling Democratic Party of Japan were more circumspect, although they did not rule out a rethink of existing nuclear policy and the 2020 emissions target.
"At the moment, we have not decided whether to review the target and we are not at a stage where we can make a decision," Chief Cabinet Secretary Yukio Edano, the number-two official in Japan's cabinet, said on Monday.
Edano said the government still needed to get a handle on the overall impact of the nuclear crisis on a variety of industries and policies, including climate change.
Katsuya Okada, the party's secretary general, told a separate news conference on Monday that it may be necessary to review the 2020 target, given its heavy reliance on nuclear energy, but the government should not rush to any conclusions while it is still dealing with an emergency.
The environment ministry's scenarios for achieving 25 percent carbon reduction are all based on a government plan to add nine new commercial nuclear reactors by 2020 to the 54 currently in operation.
More than three weeks after a devastating earthquake and tsunami in northeast Japan knocked out power sources and cooling systems at Tokyo Electric Power Co's Fukushima Daiichi plant, engineers are still struggling to cool down reactors and spent fuel pools and to contain radiation leaks.
Quake and tsunami damage and high radiation levels have forced a shutdown of the entire Fukushima complex, whose two plants and 10 reactors account for one-fifth of Japan's total nuclear capacity, while spurring the government to impose extra safety measures against a similar disaster.
Several of Japan's 10 nuclear power producers have delayed the restart of reactors taken down for maintenance, to implement additional short-term steps to bolster safety.
Some have also tentatively halted preparations for building new reactors but no plans have been formally altered, while senior government officials have talked of an energy policy review that could include promoting renewables.
Japan's carbon target for 2020 is now closely linked to its post-Fukushima energy policy, and nothing will be clear until the government, the power companies and the public decide on the future of nuclear power, said Akihiro Sawa, executive senior fellow at the 21st Century Public Policy Institute.
Complicating the issue is the prospect of power shortages in the summer, when traditionally heavy demand for air-conditioning could force rolling blackouts in the Tokyo area and deliver a severe blow to Japan's economic heartland.
"People have now realized the importance of stable energy supplies," Sawa said. "The government should start with the supply and demand outlook for energy and assess how that would affect its low-carbon policy. The government cannot review climate policy in isolation."
Tokyo Electric estimates it will be able to supply 46,500 megawatts of power by summer, after bringing some damaged and mothballed thermal power plants back online, but this would still be nearly 10,000 MW short of estimated peak demand, despite extensive conservation efforts since the quake.
Electricity demand in areas served by Tokyo Electric fell 9.2 percent in March from a year earlier, according to Reuters calculations from industry data released on Monday by the Electric Power System Council of Japan.
Tokyo Electric, which accounts for about one-third of Japan's total power consumption, resorted to rolling blackouts last month after the quake.
Nationwide, Japan's power demand fell 2.6 percent in March from a year earlier, marking the first decline in 16 months.
The government, keen to avoid the blow that blackouts could deliver to industries from autos to aluminum, is considering regulatory steps to make it easier for firms to curb power use.
These may include allowing industries to coordinate plant operating hours, to prevent concentration of power use in peak periods, which could require exceptions in enforcement of the antimonopoly law by the Japan Fair Trade Commission.
Land use restrictions that prevent setting up power generators at certain factory sites may also be waived, while labor and building maintenance rules may be eased to allow cutbacks in air-conditioner use.
The government aims to compile the measures by the end of April and implement them by July, when the summer peak season starts, a trade ministry official said.
(Additional reporting by Yoko Nishikawa and Linda Sieg; Editing by Edmund Klamann)