As the temperatures begin to dip below freezing in Europe, an unsightly conflict is heating up between clean-energy champion Germany and its pro-nuclear neighbors in Poland and the Czech Republic.

The Central Europeans claim that Germany’s fluctuating power supply – based increasingly on photovoltaic solar and onshore wind – swamps their transmission grids at peak hours thus making them highly susceptible to blackouts this winter. But the tiff is more than what meets the eye: Cheaper green electricity from Germany pushes its neighbors out of the market – and the Central Europeans thus want to block it, by force if necessary.

Indeed Germany’s clean energy transition, or Energiewende as they call it, has both friends and foes on the continent. Nations like Denmark, Austria, Switzerland, Sweden, Italy, and Spain, are all phasing out nuclear and fossil fuels in favor of renewables. Meanwhile, France and just about all of the Central Europeans believe the nuclear option is their best bet to reduce carbon emissions and keep both their factories humming and citizens warm at night.

Germany’s renewables boom and Chancellor Angela Merkel’s decision to close eight nuclear reactors in the aftermath of Fukushima have refigured the country’s energy mix. More than 26% of Germany’s electricity is now generated by renewables, mostly onshore wind and photovoltaic. When the sun is shining bright and the wind blowing strong, Germany’s renewables generate enough electricity to cover the country’s needs – and even surplus to export.

Blackout Risk Cited

In fact, Germany’s out-dated transmission grids are pushed to their limits at times of peak supply and the excess often flows over into the grid systems of their neighbors, including the Czech Republic and Poland. This is what happened last winter and the Central Europeans claim they were so overloaded that their grids nearly burst, which would have caused blackouts costing millions of euros. The more intermittent green electricity in the system, the greater is the risk and potential damage, say the Central Europeans. The Germans, they feel, launched their energy revolution without weighing its consequences or communicating with its neighbors.

This, they say, is why they’ve drawn the line with Germany, warning in no uncertain terms that this is unacceptable. The Czech energy minister Martin Kuba recently went public saying: “The overloading has increased significantly since last year. This threatens the energy security of our country. We will protect the interests of the Czech Republic.”

“The German wind energy industry doesn’t care a bit whether the lights go out in the Czech Republic,” – Zbynek Boldis of the Czech grid company CEPS.

The Czechs and the Poles, too, have thus begun building massive transformers (the Czech endeavor will cost €80 million) on their borders to enable them to shut Germany out of their systems if the situation becomes critical. They warned the Germans that they will carry out their threat if they have to.

But the Germans are pushing back, if gently for now. For one, they say, the Central Europeans are trying to justify their reliance on antiquated nuclear reactors – as well as their plans to build more in the near future. Prague hopes to increase its nuclear generation capacity share to 55% of its national supply by 2040 (It is currently at 35%.) The Poles want their very first reactor and running by 2020.

The Czechs’s operational reactors and those scheduled to be built lie close to the German border, and are opposed by Germans living there as well as all of the German political parties. The message they’re sending with the tough talk is: nuclear power is more stable and predictable than renewable energy, thus we will continue with our nuclear program regardless of German (or Austrian) uneasiness.

Moreover, by blocking the German access to their grid, they prevent Germany companies from selling their electricity, which is cheaper than that of the Central Europeans, to Austria.

“This is what it’s really all about,” says Rainer Baake, director of the think tank Agora Energiewende and former high-ranking official in the German environmental ministry. “Germany’s increase in clean energy has led to Germany’s wholesale electricity prices becoming cheaper and cheaper. Now it’s less expensive to import electricity from Germany than to produce it in coal fired power plants in Eastern Europe – let alone to build new nuclear power plants.”

The Germans admit that their present grid system is inadequate and that they are in the processes of expanding and enhancing their system. There’s no one price tag but experts estimate the total cost of the Energiewende could range from 125 to 250 billion dollars by 2020. Until then Germany will have to use parts of the Central Europeans’ north-south grids to send electric power from its gusty eastern coats to its industrial hubs in the south, as well as for distributing power at times of peak supply.

As the first snow flakes of the year fall, the Germans say that this quarrel with its neighbors, no matter how unsightly, will not force it to slow or alter the course of its clean energy transformation. The Central Europeans aren’t budging either.