Vattenfall has installed 21 of the 76 Siemens 3MW turbines at the 228MW Pen Y Cymoedd wind farm in South Wales.
The Swedish company also said it had completed 64 pre-assemblies at the site.
Installation work started in January on the 145-metre high turbines and is scheduled to be complete by the end of the year.
Daily convoys continue to bring the turbine components to the project from Swansea docks.
Image: turbines going up at Pen Y Cymoedd (Vattenfall)
Vattenfall hits 21 turbines at PyC
64 pre-assemblies also completed at 228MW project in South Wales
By EBS