The German energy company said the 160 turbines at the Gwynt y Mor offshore wind farm are in place and cables are being set so the facility can enter into service later this year.
The wind farm will have a peak operational capacity of 576 megawatts, which RWE says will be enough to meet the energy demands of about 30 percent of the homes in Wales.
RWE added that it installed the first set of 48 wind farms for the sister project, Nordsee Ost, off the German coast.
"The construction of the Nordsee Ost wind farm is making good progress," Marcel Sunier, wind energy project director for the German company, said in a statement. "We are therefore absolutely on track for the complete commissioning next spring."
Nordsee Ost will provide at its peak 295 megawatts of power, enough to meet the annual electricity demands of 300,000 German households.
Germany aims to rely on wind power to meet the bulk of its renewable energy needs.