Ruling on a case brought by Swedish group Vattenfall, the constitutional court found a payout condition set by Berlin in 2018 to be "unreasonable" as it would require energy companies to make the change first before getting compensation.

Vattenfall welcomed the decision, saying the 2018 decision "did not even begin to meet the requirements of the constitutional court" and that "new regulation requires substantial improvements".

Berlin in 2018 agreed to give hundreds of millions of euros in compensation to energy companies including RWE and E.On, bringing the country into compliance with a 2016 court ruling that found energy suppliers had a right to financial payouts over Chancellor Angela Merkel's U-turn on nuclear energy.

Merkel's government, which had earlier championed atomic power, decided in the wake of Japan's 2011 Fukushima disaster to immediately close eight of Germany's oldest nuclear plants and to shutter the other nine by 2022.

RWE and Vattenfall sued the government, arguing that their investments in nuclear energy deserved compensation.

Although Germany's constitutional court found that the government did nothing illegal, it agreed with the energy firms that they should receive "appropriate" compensation, for which German legislation had so far failed to provide.

edf/hmn/bmm

E.ON

RWE