The wind farm, which features 15 turbines, was completed late last year. It is located at 7km off the coast of Whitstable and Herne Bay.
Vattenfall vice president of business area wind Gunnar Groebler said: Kentish Flats Extension is an important addition to our European fleet of offshore wind farms.
"The innovation we have deployed at KFE takes Vattenfall on its next step towards really competitive offshore wind.
"It is also an important newcomer to offshore wind off the Kent coast. We hope that local people around Herne Bay and Whitstable will value this new wind farm."
In February 2013, Vattenfall secured a development consent order from the Secretary of State to extend the existing Kentish Flats wind farm.
The Kentish Flats Extension is on the southern side of the Outer Thames Estuary, and situated adjacent to the existing wind farm.
The site boundaries adjoin the west and southern side of the existing wind farm and cover an area of about 7.8km².
The existing wind farm has been operational since 2005 and features 30 x 3MW wind turbines with a combined capacity of 90MW.
Image: Vattenfall inaugurates Kentish Flats Extension wind farm in UK. Photos: xedos4/FreeDigitalPhotos.net.
