What is being described as the world’s largest offshore wind farm construction programme, involving the building of up to 2500 turbines 80m high has got under way with the allocation of development leases for fifteen sites around the English and Welsh coasts. If fully developed these sites would have a combined capacity of 7200 MW.

The government’s target for offshore capacity has been cranked up following a better than expected response to its call for bids for the second round of site leasing. In the event thirteen developers have won the fifteen leases, three of them (Walney, West Duddon and Gwynt y Mor) for sites off the north-west coast, eight in the north-east (Westernmost Rough, Humber, Triton Knoll, Race Bank, Lincs, Docking Shoal, Dudgeon East and Sheringham) and four in the outer Thames estuary – Gunfleet Sands, Greater Gabbard, London Array and Thanet.

A development dubbed London Array, which if fully realised would probably be the world’s largest individual offshore site, has been proposed by a consortium of Powergen Renewables, Shell WindEnergy and CORE Ltd, who have gained the opportunity to lease a site in the outer Thames Estuary. It is claimed that the wind farm could ultimately supply up to a quarter of London’s power. Shell, CORE and Powergen would each own a third of the project. Further technical and environmental studies are to be undertaken to establish viability as well as an extensive consultation process.

The current plan calls for construction in four phases. The first would be a 300 MW wind farm to be commissioned in 2007. Depending on the success of the first phase, three further phases of slightly smaller size would be commissioned in 2008, 2009 and 2010 respectively. The full development would generate around 1000 MW from up to 300 turbines.

The farm would be located around 20 km out to sea where it is expected to be of little visual impact, but should contribute significantly to meeting the UK’s target for increasing the proportion of electricity generated from renewables by 2015. If built, the wind farm would prevent 1.3 million tonnes/year of greenhouse gas emissions.

A second lease, to build and operate a 500 MW windfarm 25 km offshore at Greater Gabbard in the outer Thames estuary has been granted to a consortium of Airtricity and Fluor. Airtricity is already well known for its Arklow Bank project. This project consists of a single site at twin sandbanks known as the Inner Gabbard and the Galloper. It is regarded as ideal for reasons of wind speed, shallow water, and suitable ground conditions.

•An even larger project may materialise if German developer WPD AG is granted planning

permission for the Hochsee-windpark Nordsee at a site located in the North Sea 100 km north of Borkum island where it hopes to erect 508 x 4.5 MW units amounting to 2286 MW.

Such a wind farm would be among the biggest in the world, offshore or otherwise.