By Arno Schuetze and Patricia Uhlig
FRANKFURT (Reuters) - RWE should look at speeding up its shift away from carbon, two top-20 shareholders said on Thursday, adding to pressure after activist fund ENKRAFT took a stake in Germany's largest power producer and urged it to hive off lignite assets.
"A debate on the speed of CO2 reduction is to be welcomed, and major structural changes in the group must not be taboo", said Ingo Speich at fund manager Deka, which has a 0.9% stake in RWE according to Refinitiv Eikon data.
He added talks should be conducted with a sense of proportion and include the social implications of such a move.
Thomas Deser, a fund manager at Union Investment -- which has a 1% stake -- agreed.
"We see a high and urgent need for the transformation of the RWE business model towards a significant reduction of the CO2 profile", he said.
The remarks came after ENKRAFT said RWE should separate its brown coal activities, which have weighed on the value of its shares, adding RWE was "no longer investible" for many under stricter sustainability criteria.
Shares in RWE rose as much as 1.7% on Thursday to 33.3 euros per share following the news. ENKRAFT estimates that RWE's share price has potential to rise to more than 61 euros per share.
RWE has undergone a shift in recent years and is now one of Europe's largest renewable players. It still operates legacy nuclear and coal assets, both marked for gradual shutdowns.
(Additional reporting by Christoph Steitz; Editing by Mark Potter and Bernadette Baum)