The German engineering conglomerate and energy companies have agreed to invest in 160 wind turbines for the Welsh-named "Gwynt y Môr” project, expected to power 400,000 British homes.
Located 13 kilometres from the shore of North Wales, the 124-square-kilometre wind park will be completed in 2014, though it will begin providing electricity in 2013.
RWE's renewable energy subsidiary RWE Innogy has taken on 60 percent of the project, while SWE will invest in 30 percent, and RWE 10 percent. Altogether they will invest more than €2 billion.
The three companies said the 567 Megawatt wind park is the largest ever to receive investment funds, though another much larger 9,000 Megawatt project on the Dogger Bank area of the North Sea is in early planning stages. That park will generate energy equivalent to that of seven power plants.
It will be RWE's fifth wind park and part of the energy company's goal to increase its use of renewable energy from less than five percent to 30 percent.
On Friday RWE Innogy head Fritz Varenholt criticised Germany's sluggish construction of wind parks off its own shores.
“We don't have our act together,” he said. “It's unacceptable.”