The farm's 58.5MW capacity will allow it to supply 42,000 homes with electricity, representing 20% of Wales' total installed wind power capacity.
Cefn Croes has almost twice the power output of the largest wind farm previously operating in Wales, but Welsh environmental groups claim its estimated lifetime saving of four million tonnes of carbon dioxide is outweighed by the blighting of an otherwise pristine countryside.
"We think Wales' landscape is being traded for a quick energy fix," said Peter Ogden, director of the Campaign for the Protection of Rural Wales.
"The Government should be developing offshore and marine technology, which is much more effective."
Roger Jones, asset manager for Italian-based developers Falck Renewables, says the site, as well as producing minimal noise, is not even visible from the nearby main road.
"We believe this is an example of the future of green energy production in Wales," he said.
"This is the most powerful onshore wind farm in the UK, and ultimately sites like Cefn Croes will have an impact on greenhouse gas emissions."
Wales currently houses around 277 turbines across nine windfarms, with over 300 more turbines in the planning stage, with the Welsh Government publicly stating that wind farms were the only way to meet mandatory clean energy targets.
