SCOTTISH Power Renewables and Denmark's DONG Energy have contracted a German firm to supply and maintain turbines for the giant windfarm they are developing in the Irish Sea.

The firms have signed agreements with Siemens worth more than £500 million under which it will supply 108 turbines for the West of Duddon Sands windfarm.

The site lies around eight miles south-west of Barrow in Furness.

ScottishPower Renewables and DONG are 50:50 partners in the £1.6 billion project.

The turbines will tower almost 150 metres above the waves when they are deployed. In total they are expected to generate 389 megawatts at full capacity.

The windfarm is expected to provide enough power for around 300,000 homes following its expected completion in 2014.

The turbine order marks a significant coup for Siemens, which has been contracted to maintain the turbines for five years.

It will manufacture the giant components in Denmark. The turbines will have 120 metre rotors and will stand 146 metres high to blade tip from mean sea level.

Asked whether any UK manufacturers had been in the running for the contract, a spokesman for ScottishPower Renewables said it considered all the market. The turbines will be prepared for installation at Belfast Harbour before being shipped to the windfarm site.

DONG is supporting work to upgrade Belfast Harbour to make it one of the first bespoke offshore wind installation ports in the UK.

This could compete with ports in Scotland in what is expected to become a huge market.

ScottishPower Renewables also plans to develop the 500- turbine Argyll Array off Tiree which would dwarf West of Duddon Sands.

The company’s offshore arm is run from Glasgow.

Maintenance work on West Duddon will be completed out of the port of Barrow.