Berlin  ­ What do the farmers of Lower Saxony, anti-fascist skinheads, and a Munich mothers' association have in common? Not much - apart from the fact that they're all against nuclear energy.

These groups are part of a surprisingly disparate anti-nuclear movement in Germany that in early September staged probably the largest and most colourful demonstration in an otherwise dreary election campaign.

Some 40,000 people marched in Berlin - complete with a convoy of tractors, a mock-up nuclear waste transporter, a Trojan horse, and effigies of babies scorched by nuclear winds - to remind the government that a solid majority (57 per cent, according to recent polls) of Germans support the planned shut-down of the country's 17 nuclear powerplants.

According to the Phase-Out Law negotiated by a previous Social Democrat (SPD)-Green government in 2001, those plants, which currently produce around 25 per cent of Germany's electricity, would be gradually closed down by 2020 - in most cases around ten years earlier than scheduled.

But it may not stay that way, if Chancellor Angela Merkel's Christian Democrats (CDU) wins the election and manages to form a government with the liberal Free Democrats. Both parties, while rejecting building any new nuclear plants, would like to keep the old ones running a bit longer.

"The most important thing is that we transfer to renewable energy as quickly as possible ... but do we have to pull out by 2020, or could we not have a bit more time?" Merkel asked the nation, rhetorically, during the TV debate with rival Social Democrat challenger Frank-Walter Steinmeier on September 13.

This wish to keep the reactors humming - just in case - has infuriated a huge swathe of political opinion, from the far-left to the SPD, with whom Merkel currently governs.

And a string of events in the run-up to the election has served to undermine what little public trust there was in Germany that the nuclear industry can run itself safely and transparently.

In July a nuclear plant at Kruemmel, in Schleswig-Holstein, broke down just days after a two-year shutdown prompted by an earlier accident.

In August it emerged that the German government under Chancellor Helmut Kohl in the 1980s had suppressed scientific evidence against using an underground salt cavern at Gorleben (under the rich farmland of Lower Saxony) as a permanent nuclear waste storage site
- and went ahead with it anyway.

The site has sucked up billions of dollars over the years, and is still not ready to be used as a storage site.

Then a few days later it was revealed that the level of plutonium waste at Asse, a temporary storage site also in Lower Saxony, was three times higher than had been previously admitted.

The Green Party, the Left Party and the SPD have made the observation of the Phase-Out Law a central plank of their election campaigns.

SPD leader Steinmeier, who calls the Kruemmel power-plant the on- again, off-again monster", and insists that a return to nuclear energy is irresponsible."

But switching off ­ even over a period of ten years ­the source of more than a quarter of Germany's electricity will be no mean feat. The first issue is energy supply security, in which diversity is the key.

In the short term, "shutting off nuclear would mean using more fossil fuels, especially gas. That extra gas would have to be imported, very likely from Russia and Norway," says Miika Tommila, an analyst at the Paris-based International Energy Agency.

"To replace nuclear with low-cost renewables would be impossible in such a short time," he says.

The final, and perhaps most important, factor, is climate change - greatly exacerbated by fossil fuels, especially coal.

Germany has pledged to reduce its carbon dioxide (CO2) output by nearly 40 per cent over 1990 levels by 2020. As nuclear plants produce practically no carbon dioxide, a concurrent nuclear shutdown makes this goal a lot harder to reach.

Nevertheless, opposition to nuclear power runs so deep that if the election throws up a CDU-FDP coalition, who then decide to discard the Phase-Out, the farmers, the mothers, and the Skinheads, will be back on the streets, placards in hand. (dpa)