RWE, one of Germany’s biggest energy companies, is to become the sixth company backing the proposed Nabucco pipeline to bring gas from the Caspian region to Europe, bolstering hopes for the troubled plan.

RWE is expected to be formally announced as a member of the consortium at a ceremony in Vienna next week, joining five companies from Austria, Hungary, Romania, Bulgaria and Turkey. RWE on Friday would not confirm the reports, saying only that it had expressed its interest in Nabucco and was “very happy about these positive signals”.