Judges praised the development’s outstanding construction, environmental, and health and safety standards.
The 76-turbine wind farm is the largest onshore wind farm in England and Wales.
The project’s local employment policy resulted in 65 per cent of the workforce employed from within a 35 mile radius of the site.
200 people were employed at the peak of construction, benefitting the local economy through pay packets being reinvested in the area.
The joint venture established a ‘Wave Hello: Wave Goodbye’ scheme to protect pedestrians and cyclists from heavy plant vehicles on the 4,600 hectare land.
The programme instructed visitors to make visible contact with plant operatives to alert them of their presence on the site.
Zero waste was sent to landfill, as the project extracted and processed 700,000 tonnes of rock on the site, reducing demand for haulage vehicle journeys to and from the South Wales valley.
Eryl Roberts, joint venture project manager, said: “This award is recognition of the project’s high standards, which went beyond excellence in construction.
“92 per cent of all labour was sourced from within Wales, and the site was rated number one by Vattenfall for health and safety on their worldwide projects.
“The project also benefitted the community, with 400 school visits made to the site during construction.”
Pen Y Cymoedd is owned and operated by Vattenfall and generates enough electricity to power 188,000 homes