Thousands of homeowners will be among the first in Wales to help tackle global warming by receiving their electricity from one of 30 wind turbines.
The first wind turbine has been installed in Denbighshire
More than 50,000 homes throughout Denbighshire will get their power supplied by the windfarm in the middle of the Irish sea.
The first of the 150m-tall towers was erected off the coast of Prestatyn on Tuesday.
Now eco-minded residents can pay their electricity bills direct to a company which has set up a joint venture with environmental campaign group Greenpeace.
The turbines will provide up to 60 megawatts of electricity for npower's domestic electricity product Juice.
The North Hoyle site, scheduled for completion later this year, is located 7.5km off the north Wales coast.
"This pioneering windfarm will lead the way towards...bigger developments in UK waters that we so urgently need to help tackle global warming," said Stephen Tindale from Greenpeace.
Excalibur puts the finishing touches to the wind turbine
"The first turbine installed at North Hoyle represents a crucial milestone on the road to clean energy in the UK."
In order to erect the turbines, construction workers have had to tow the huge turbines one-by-one from the Port of Mostyn where they were built.
National Windpower, the company behind the North Hoyle scheme also has planning consent to build a second offshore windfarm at Rhyl Flats near Abergele.
A company spokeswoman said they are still discussing how best to take the project forward.
The Department for Trade and Industry has committed the UK to generating 10% of its electricity from renewable sources by 2010, and the installation of the first turbine in Denbighshire is a major step towards achieving this figure.