Germans are braced for blackouts

But it is still bracing for blackouts of the kind not seen since the Second World War as overnight eight of the country’s 17 reactors were switched off in a populist move that is now seen as a rash decision.

The government’s official plan is to retire the remaining nine reactors by 2022 and power the country without nuclear energy, instead relying on growing renewable energy sources.

But domestic customers and companies are nervous about whether their lights and assembly lines will stay up and running this winter, and economists and politicians are arguing over how much prices will rise.

Joachim Knebel, chief scientist at Germany’s prestigious Karlsruhe Institute of Technology, said: “It’s easy to say, ‘Let’s just go for renewables,’ and I’m quite sure we can someday do without nuclear, but this is too abrupt.”

He described the government’s shutdown decision as “emotional” and pointed out that, on most days, Germany has survived this experiment only by importing electricity from France and the Czech Republic, which generate much of their power with nuclear reactors.

Juergen Grossmann, chief executive of the German energy giant RWE, which owns two now-closed reactors in Biblis, about 40 miles south of Frankfurt, said: “Germany, in a very rash decision, decided to experiment on ourselves. The politics are overruling the technical arguments.”

Germany’s planners believed they could forgo nuclear energy in large part because of the country’s remarkable progress in renewable energy, which now accounts for 17 per cent of its electricity output, a number the government estimates will double in ten years. On days when the offshore wind turbines spin full tilt, Germany produces more electricity from renewable sources than it uses.

With a total of 133 gigawatts of installed generating capacity in place at the start of this year, “there was really a huge amount of space to shut off nuclear plants,” Harry Lehmann, a director-general of the German Federal Environment Agency said of the plan he helped develop.

The country needs about 90.5GW of capacity on hand to fill a typical national demand of about 80GW a day. So the 25GW that nuclear power contributed would not be missed – at least within its borders.

To be prudent, the plan calls for the creation of 23GW of gas- and coal-powered plants by 2020 as renewable plants don’t produce nearly to capacity if the air is calm or the sky is cloudy.

German energy companies say they have been handed a national energy template that looks good on paper but is technically challenging. Although the country’s production of energy is bounteous, they say it is not always available where and when it is needed.

Northern Germany has offshore wind and coal deposits, but southern Germany – a manufacturing centre home to carmakers Mercedes, BMW and Audi – has no plentiful local fuel source other than nuclear. Germany’s current grid is highly decentralised, lacking high-voltage transmission lines to move electricity over long distances.

“Now, with the nuclear shutdown, we have a very difficult task,” said Joachim Vanzetta, head of transmission system operations at Amprion, the largest of the country’s four grid operators.

Germany’s hope that gas and coal plants will temporarily replace some of the lost nuclear generation may be hard to fulfil – power companies remain lukewarm about building them, especially given the policy of buying “clean” energy first.

“Few operators will be willing to build a power plant in a form that may ultimately only run a couple of hundred hours a year,” Mr Grossman of RWE said.