Energy company Airtricity and multinational engineering group Fluor will spend €750 million on buying turbines for a joint offshore electricity windfarm in the UK.

The companies are planning to develop a windfarm with the capacity to produce 500mw (mega watts) of electricity, which is enough to power 415,000 homes in the outer Thames Estuary in the southeast of England.

The partnership, known as Greater Gabbard Offshore Wind Ltd (GGOWL), has signed a deal with a German manufacturer to buy 140 wind turbines, which will be used to generate the electricity.

While neither company would reveal the purchase price for the turbines, it is understood that it is in the region of €750 million.

The turbines will each be capable of generating about 3.6mw of electricity.

There is a global shortage of turbines as Siemens is the main manufacturer and the rate at which windfarms are being planned and developed means that demand is outstripping supply.

In that context, Airtricity chief executive Eddie O'Connor said that securing the deal announced yesterday with Siemens was a "major coup" for the Irish company and its multinational partner.

Fluor's managing director, Patrick Flaherty, pointed out that the multinational group has been doing business with Siemens for many years.

Mr Flaherty described the deal as "a major milestone".

Airtricity and Fluor plan to begin building the windfarm in 2009 and expect it to be up and running by the end of the following year.

The companies are currently tendering for building materials and equipment.

Airtricity is 51 per cent-owned by NTR and is an Irish-based alternative energy group that is developing windfarms in Ireland, Britain, Europe and the US.

Its projects include an 800mw farm planned for Texas in the US, a 300mw plant off the German coast in the Baltic Sea, and four windfarms to the west of the Netherlands in the North Sea.

Fluor is a New York-listed construction, engineering, project management and maintenance group, with operations around the globe.