BERLIN — Swiss voters have rejected a plan to force their government to accelerate the country’s exit from nuclear energy.
A majority of cantons voted against the plan in Sunday’s referendum. Under Switzerland’s direct democracy system, proposals need a majority of both the states and overall votes to pass.
The plan promoted by the Green Party would have meant closing three of Switzerland’s five nuclear plants next year, with the last shutting in 2029. A projection for SRF public television showed the initiative failing by 55 percent to 45.
After the Fukushima nuclear disaster in Japan, the Swiss government adopted a gradualist approach toward transitioning the country to renewable energy by 2050.
The five Swiss nuclear power plants now generate 40 percent of the country’s electricity.
A similar movement is underway in neighboring Germany, where officials are stepping up transition to renewables like solar energy in time to be done with nuclear energy by 2022, a deadline also set after the Japanese tsunami.
As part of an energy plan that runs through 2050, the Swiss government has already agreed not to replace its existing nuclear plants, which can operate as long as they’re deemed safe. The plants are to be closed progressively as their life spans expire, and the government says it needs time to switch to other sources such as wind, solar, and biomass energy.
Switzerland regularly holds referendums as part of its particular form of direct democracy, which allows voters in the country of about 8.2 million to set policy on major issues — at times causing hassles for officials to carry out the public’s will.
The two chambers of the Swiss legislature and the executive Federal Council have variously argued that the earlier shutdown of the nuclear energy program would have forced Switzerland to import more electricity, such as from carbon-spewing coal-fired plants in Germany.
Plus, early shutdowns could make the government — and thus taxpayers — liable to pay penalties to the nuclear plant operators.
‘‘The initiative will compromise the security of our energy supply,’’ Federal Councilor Didier Burkhalter warned in a government video.
But Ilias Panchard, secretary general of a group whose French name translates as ‘‘Get Out of Nuclear,’’ said Switzerland’s nuclear power complex is dangerous, aging, and beset by problems — with two of the five Swiss plants not operating at the moment for safety or technical reasons.
His group insisted that now is the time to set a fixed timetable, before it’s too late to move to a proper replacement.
‘‘If we just wait until an accident or a problem with the plants, then we do not have the time, the energy to replace it. So the idea of the initiative, the referendum, is to say: In 2029 we will have no more nuclear energy in Switzerland,’’ he said in an interview in Geneva.
The initiative would have limited the life span of nuclear plants to 45 years, and force the closure next year of three of the plants, Beznau 1 — which Panchard called the world’s oldest operating nuclear plant, built in 1969 — as well as Beznau 2 and Muhleberg.
‘‘Concretely, that means that in 2017, about one-third of the electricity generated by nuclear energy will be lacking. That amounts to the average annual electricity consumption of close to half of Swiss households,’’ Burkhalter said, adding that renewables won’t be able to make up the difference right away.
Two other plants would shut over the next 13 years: Goesgen would close in 2024 and Leibstadt in 2029.