The power plant, which has a generating capacity of 553MW, also supplies district heating to the grid operated by the Stadtwerke Rostock municipal works.
RheinEnergie is also acquiring German power group RWE’s 24.6% stake in the power plant, while the remaining 50.4% interest is held by EnBW.
German utility EnBW acquired the 50.4% stake in the power plant from E.ON in 2009.
Vattenfall Europe CEO Tuomo Hatakka said that the sale of the company’s share is the next step in its ongoing strategy of consistently divesting its minority interest.