Germany on Monday became the first major industrialised power to agree an end to nuclear power in the wake of the disaster in Japan, with a phase-out to be completed by 2022.
Chancellor Angela Merkel said the decision, hammered out by her centre-right coalition overnight, marked the start of a "fundamental" rethink of energy policy in the world's number four economy.
"We want the electricity of the future to be safer and at the same time reliable and affordable," Merkel told reporters as she accepted the findings of an expert commission on nuclear power she appointed in March in response to the crisis at Japan's Fukushima plant.
"That means we must have a new approach to the supply network, energy efficiency, renewable energy and also long-term monitoring of the process," said Merkel, whose popularity had suffered over her previous pro-nuclear stance.
The commission found that it would be viable within a decade for Germany to mothball all 17 of its nuclear reactors, eight of which are currently off the electricity grid.
Environment Minister Norbert Roettgen announced the gradual shutdown early Monday after seven hours of negotiations at Merkel's offices between the ruling coalition partners. He said the decision was "irreversible".
Seven of the reactors already offline are the country's oldest, which the government shut down for three months pending a safety probe after the Fukushima emergency.
The eighth is the Kruemmel plant, in northern Germany, which has been offline for years due to repeated technical problems.
Six further reactors are to be shut down by the end of 2021 and the three most modern would stop operating by the end of 2022.
Monday's decision, which could run into legal challenges from energy companies, means Germany will have to find the 22 percent of its electricity needs that were covered by nuclear power from other sources.
Roettgen insisted there was no danger of blackouts.
"We assure that the electricity supply will be ensured at all times and for all users," he pledged.
The government must now determine how it can make up the difference with renewable energy sources, natural gas and coal-fired plants.
Merkel's spokesman Steffen Seibert said the plan would uphold four priorities: Germany's standing as a top global economy, an affordable and sufficient energy supply, climate protection and independence from energy imports.
The decision is effectively a return to the timetable set by a previous Social Democrat-Green coalition government a decade ago.
It is a humbling U-turn for Merkel, who at the end of 2010 decided to extend the lifetime of the reactors by an average of 12 years, which would have kept them open until the mid-2030s.
That decision was unpopular even before the earthquake and tsunami in March that severely damaged the Fukushima facility, sparking mass anti-nuclear protests in Germany.
Merkel's zig-zagging on what has been a highly emotive issue in the country since the 1970s cost her in recent state elections as the anti-nuclear Greens gained ground.
Nuclear opponents slammed the deal Monday and said they would stage fresh demonstrations next month calling for a faster phase-out.
Meanwhile industrial giant Daimler warned the shutdown would undermine the competitiveness of Europe's top economy.
"Turning our backs on an affordable energy supply is clearly a risk," chief executive Dieter Zetschke told the daily Bild, adding that he saw the decision as "strongly coloured by emotions".
The Fukushima accident has sparked a renewed global debate about the safety of nuclear power, with opinions differing widely.
Sweden's environment minister criticised Germany's decision, saying it would lead to a disjointed energy policy that failed to adequately address climate change.
The United States and Britain have announced plans to build new reactors as an alternative to producing harmful greenhouse gas emissions while ensuring a relatively cheap supply of energy.
Italy scrapped nuclear power in 1987, one year after the Chernobyl disaster, while neighbouring Switzerland said last week it would phase out atomic energy by 2034.
Nuclear power: top producers worldwide
Germany's decision to give up nuclear energy production by 2022 would reduce the total number of commercial reactors worldwide by less than four percent.
With a total of 17 units out of 440 worldwide, the country has 3.8% of the world's operable nuclear power reactors, according to data from the World Nuclear Association.
The following figures show the 10 biggest nuclear energy-producing nations worldwide, listed in terms of total output as of 2009.
The table also shows the total number of operable reactors for each state, as of April this year, and the percentage of total demand that is provided by nuclear energy.
Eight of Germany's reactors are currently not supplying energy to the power grid, and the Berlin authorities say the present share of nuclear power in the country's total energy output is 22%.
As of 2009, nuclear energy accounted for 13.8% of total world production of electrical energy, according to the World Nuclear Association.
The catastrophic earthquake and tsunami that hit Japan on March 11 this year knocked several of that country's nuclear reactors out of action.
COUNTRY / NO. REACTORS
United States / 104 798.7
France / 58
Japan / 51
Russia / 32
Germany / 17
South Korea / 21
Canada / 18
Ukraine / 15
China / 13
Britain / 19