Located in North Wales, the 96MW onshore wind farm is equipped with 27 wind turbines, which have the capacity to power 63,800 UK homes with clean energy.
Jones Brothers Civil Engineering UK served as the principal contractor for the project.
The £20m contract created nearly 60 jobs and represents a £118m investment in new clean energy infrastructure in Wales.
RWE UK and Ireland Onshore Development head Cathal Hennessy said: “RWE ensures that it works closely with local communities throughout the development of renewable projects; to ensure there is a long-lasting benefit from the delivery of its projects to the local area, as well as to the environment.”
Clocaenog Forest had been completed and operational for more than a year, but RWE postponed the inauguration event due to Covid-19 restrictions.
RWE UK country chair Tom Glover said: “Celebrating the opening of an onshore wind farm of this scale is truly inspiring.
“RWE is the largest renewable generator in Wales, with a long and proud history of pioneering wind power in the country.
“Having invested well over £3bn in Welsh energy projects over the last decade, we are committed to further green growth and to being a key partner in delivering Welsh Government aims of meeting the country’s electricity needs with renewable energy by 2035.
“Clocaenog will make a significant contribution to this aspiration, while also establishing a positive and enduring legacy for the local community.”
Earlier this month, RWE partnered with Greece-based oil firm Hellenic Petroleum Holdings to explore offshore wind opportunities in Greece.
The companies will focus on the development, construction and operation of wind farms off the Greek coast via their respective subsidiaries, RWE Renewables and HELPE Renewables.