In 2002 the world’s largest offshore wind farm was constructed off the Danish west coast. The Horns Rev wind farm is sited 14-20 km into the North Sea, west of Blåvands Huk, and represents the first phase in the Danish Government’s ambitious plan - to have wind turbines with a total capacity of 4000 MW in Danish waters before 2030.

Airtricity on Wednesday announced that construction of the 504MW Greater Gabbard offshore wind farm, in the outer Thames Estuary, will begin shortly. Once completed, with an investment of £1.3 billion (€1.6 billion), it will be the world’s largest offshore wind farm.

As the renewable arm of Scottish and Southern Energy Group (SSE), Airtricity is a world leading renewable energy company developing and operating wind farms across Europe and Asia. The company has 24 wind farms in operation throughout Ireland and the UK resulting in over 600MW. A further 7 wind farms totaling over 100MW are under construction. Airtricity was founded by Irish entrepreneur Eddie O'Connor and sold by NTR Plc (formerly National Toll Roads) e

The development of the wind farm to this stage has been carried out by Greater Gabbard Offshore Winds Ltd, a 50:50 joint venture between Airtricity, now SSE’s renewable energy development division, and Fluor International Limited.

Airtricity has now entered into a contract with Fluor Limited for the design, supply, installation and commissioning of the balance of the plant. Having secured the construction contract, Fluor International Limited has agreed to sell its 50% stake in Greater Gabbard Offshore Winds Ltd to Airtricity for £40m in cash. Airtricity intends to sell 50% of the project equity later this year.

A turbine reservation agreement with Siemens Wind Power A/S for the supply of 140 3.6 MW turbines was secured in 2007 and both parties have now agreed the turbine supply contract and the five-year service and warranty contract for the development.

The wind farm site covers two offshore areas, Inner Gabbard and The Galloper, which are located approximately 25km off the Suffolk coast, in the outer Thames Estuary. The 140 turbines will be mounted on steel monopiles and transition pieces, in water depths between 24 and 34 metres. Three 132kV sub-sea cables will bring the power ashore to a new substation to be built near Sizewell.
The wind farm is expected to have a load factor of over 40%, based on site-specific met mast data collected since 2005. It will be commissioned in two phases, with the entire construction scheduled to be completed in 2011.

Airtricity’s target of around 4,000MW of operating renewable energy capacity in the UK and Ireland by 2013 includes a 50% share of the capacity of Greater Gabbard. The development, excluding the connection, is expected to require investment of around £1.3bn. Airtricity will fund its 50% share either from its balance sheet or through non-recourse project finance. It also expects to take 50% of the output of Greater Gabbard, with the remainder being the subject of a separate agreement with another power purchaser.

Welcoming the announcement, UK Business Secretary John Hutton said: "Airtricity’s investment in Greater Gabbard is very welcome and a prime example of the increasing number of renewable projects that are now taking place across the UK. The massive potential of the UK shoreline coupled with the right market conditions mean the UK is one of the most attractive places in the world to invest in offshore technology.

“Through the Energy Bill we are providing more financial support to offshore projects, and in the summer we will be setting out our plans to increase renewables further. Tackling climate change and securing future energy supplies is of the utmost importance and a vast expansion of both onshore and offshore wind will be central to this.”

Paul Dowling, Chief Executive of Airtricity, said:“Ireland and the UK wants to respond to climate change and become more self-sufficient in energy, so it makes sense to exploit the excellent resource that UK offshore wind represents. On completion, Greater Gabbard will be the largest offshore wind farm in the world and gives Airtricity the opportunity to build a significant share of the UK’s offshore wind market and reinforce our position as the country’s leading generator of electricity from renewable sources.

“Greater Gabbard is a landmark project for Airtricity and for the development of the UK’s offshore wind resource, and our priority now is to deliver it in an efficient, focused and timely manner. A major construction project of this kind, in potentially challenging conditions, is not without risks, but these have been managed through the procurement and project management strategies which we have adopted.

”We are actively planning further offshore projects in the UK and throughout Europe, and the successful partnership approach that we have taken on Greater Gabbard will underpin our participation in the next round of offshore developments and beyond.”