RWE, the country's second-biggest electricity generator, got the green light on Tuesday to sue the state of Hesse for closing its Biblis nuclear power station without going through the proper legal procedure to do so.
The Federal Administrative Court ruled that RWE could sue the state, confirming an earlier verdict in a lower court from last February - and cutting off any chance for Hesse to appeal.
That initial verdict said Hesse had made mistakes in its shut-down, failing to give RWE a fair hearing at the time - and this undermined the legality of the process.
The verdict applies only to the three-month moratorium which shut down the Biblis nuclear power stations A and B in March 2011, immediately after the Fukushima disaster.
After that initial period, the two Biblis generators along with six other German nuclear power stations were removed from the electricity grid, leaving just nine nuclear power stations, which are due to be likewise shut down one by one, with Germany being nuclear free by 2022.
This wider shut-down was based on changes in the nuclear power law and is part of Germany's switch to renewable energy, known as the Energiewende.
For now, RWE is preparing a claim for damages, a spokeswoman told the Frankfurter Rundschau newspaper. Although the company is not commenting on how high its claim might be, experts told the paper that anything up to €200 million could be realistic.
Head of the new Hesse government, Volker Bouffier, from Angela Merkel's Christian Democratic Union, said he would check the verdict before commenting. "It is not a decision about whether and if, how much compensation would be due," he said.
Business newspaper the Handeslblatt said on Wednesday that Eon, another electricity generator, was checking to see if it would make a compensation claim against the states of Bavaria and Lower Saxony for losses it incurred during the same period.
Federal Environment Minister Barbara Hendricks said she would respect the court's verdict, but added: "The decision does, however, not change the fact that the departure from nuclear power is irreversible."
In a separate development, the European Commission seems to be scrapping its insistence that member states hold to concrete targets in their expansion of renewable energy generation.
The Süddeutsche Zeitung reported on Wednesday that Commission president José Manuel Barroso has argued in favour of dropping the binding nature of targets after 2020.