The 28 turbine wind farm has actually been generating electricity since Nov 13, but it was only today that Mr Key flicked a ceremonial switch high on the Wharauroa plateau in front of 250 dignitaries.
''It's massive,'' Mr Key said.
''Those are massive turbines.
''Because you so often see them from far away they don't look as large as when you come and stand next to them.
''But I think they are very graceful.''
So far 22 turbines have been installed with 17 producing electricity.
All 28 are expected to be operating by early March, generating enough power for 30,000 homes.
The wind farm is a joint alliance between Meridian Energy and Wel Networks and is the first generation project of its type in New Zealand between an electricity generator and a lines company.
Meridian chief executive Tim Lusk said it was a proud day for the company.
''This wind farm is going to be one of the most productive in the world,'' he said.
''Wind patterns at Te Uku mean that we will get twice the energy out of the turbines compared to that of the average wind farms elsewhere in the world.''
- Waikato Times