The Swiss Senate's endorsement yesterday (28 September) follows a June vote by the lower chamber to back the gradual shutdown of nuclear energy plants recommended in May by the government, which has frozen plans for a new construction programme in the wake of the Fukushima atomic plant explosion.
Switzerland is following in Germany's footsteps, which decided in May that it will shut all its nuclear reactors by 2022.
The Swiss government estimates that phasing out nuclear power in the Alpine country would cost up to SFr3.8 billion (€3.1 billion).
The Social Democrats, the Greens as well as the Christian Democratic Party hailed the Senate decision as an important step towards a new energy policy amid calls to switch to more renewable energy resources.
Bern said it would boost the development of its already viable hydro-electric plants and other renewable energy to make up for the loss of nuclear power, while not ruling out importing electricity.
If deemed necessary, Switzerland could also rely on electricity produced by fossil fuels, a government statement said, while still respecting targets set under Switzerland's climate change policy.
Environment and Energy Minister Doris Leuthard stressed that nuclear energy was anyway becoming more expensive, due to the rising cost of making plants safer and more secure.
"If we succeed in promoting new technologies it is an investment in the name of our children for Switzerland's future," she reportedly said, acknowledging open questions remained. "What is important though is that we make a start now. I call on you to have confidence in the government that this is the right way into the future and that we can tackle it together and with the support of all responsible-minded citizens," she reportedly added.
The association of Swiss electricity companies applauded the decision for a progressive end to nuclear energy, rather than an immediate stop.
"The continuation of these plants gives us time to find solutions amid a shortage as well as implement more efficient measures," it said.
The government recommended to shut down the plants of Beznau I in 2019, followed by Beznau II and Muehleberg in 2022, Goegen in 2029 and Leibstadt in 2034.
The private Swiss Energy Foundation which promotes better energy efficiency, said parliament was sending a clear signal to the business community and to society.
However, the Swiss Business Federation EconomieSuisse criticised Parliament for banning the construction of new nuclear power plants as irresponsible. "Such a strategy has to show the impact of a nuclear opt out on the security of supply, for the businesses, the independence of Switzerland and the environment," a statement said.
Discussions on nuclear power are due to continue in the new parliament which is due to convene for the first time in December following general elections next month.