Druzhba feeds not just Leuna but also the PCK Schwedt refinery, majority-owned by Russia's Rosneft.

Poyanne said Russian oil use in May had fallen to filling 555,000 tonnes of refinery capacity at the plant, down from 900,000 tonnes last October, and 800,000 tonnes in February.

"In December 2022, we will have 450,0000 tonnes left from the contracts that we have to honour - unless sanctions are taken in the meantime - and it will be zero from 2023 onwards," said Poyanne.

European companies and governments are trying to wean themselves off Russian supplies to avoid breaching sanctions and suffering reputational damage.

TotalEnergies had reserved transport capacities of around 700,000 tonnes from Gdansk to Leuna, accepting this would add to costs, Poyanne said.

The oil would mostly come from the North Sea but globally operating TotalEnergies may also be able to bring in supplies from Africa or elsewhere, he said.

It was also in discussion with the German government about cooperating on supply options arising for Schwedt in order to try to source its missing 100,000 or 200,000 tonnes that way, he added, without elaborating.

German economy minister Robert Habeck is working on solutions for Schwedt, whose other shareholders are Shell and ENI, which include use of national oil reserves and using the German port of Rostock and possibly Gdansk.

Habeck is also preparing for change of control at Schwedt, with one option being expropriation, as a new legislative amendment makes it easier for the government to take over supply-critical assets to prevent disruptions.

(Reporting by Benjamin Mallet, writing by Vera Eckert, editing by David Evans)