The announcement came after British Prime Minister Rishi Sunak said at the COP climate conference in Dubai earlier on Friday that the two companies had committed to invest up to 11 billion pounds ($13.9 billion) in the project.
Britain, which is already the world’s second largest offshore wind market after China, is seeking to ramp up its capacity to 50 gigawatts (GW) by 2030 from around 14 GW now, to help meet its climate targets and boost energy security.
Construction of the Dogger Bank South offshore wind project in the North Sea could start in 2025, with first power of around 800 megawatts by 2029 and full capacity by late 2031, RWE said.
The project, in which RWE will have a 51% share and Masdar a 49% share is made up of two 1.5 GW windfarms.
RWE did not disclose any details on the likely cost of the project.
Masdar said its decision to aquire the 49% stake in the project from RWE was part of an 11 billion pound investment in Britain's renewable sector.