The Klim Fjordeholme project entered operation in 1996. It used 35 Vestas V44 600kW turbines, which Vattenfall dismantled in 2014.
The turbines have been sold for reuse at projects in Ireland, Italy and other countries, Vattenfall said.
In their place 22 Siemens 3.2MW turbines have been installed with a hub height of 94 metres — more than double the old turbines hub height, which stood at 40 metres.
The new turbine has a 130-metre diameter rotor compared with the Vestas turbines' 44-metre rotor.
All of the concrete foundations had to be removed or replaced. Vattenfall said it used 1.1 tonnes of dynamite to remove the concrete and steel bases. The concrete was then crushed to be reused for road construction, while the steel was melted down to be recycled.
The repowered Klim project is due for completion in 2016 and will become Denmark's largest onshore wind project.
Pictures courtesy of Michael Bo Rasmussen/Vattenfall.