UK: Final Survey at Dogger Bank Offshore Wind Farm

The final survey needed for offshore wind energy developer Forewind to complete its planned applications for the development of the Dogger Bank Zone begins this week.

The survey concludes the most extensive study of an offshore area by a wind energy developer ever undertaken. A total of £60 million has been spent on surveys with the vast majority of work going to UK-based contractors.

Forewind’s aim has been to thoroughly map and characterise the 8660 km2 zone, located between 125km and 290km off the UK coast, which could be the site for at least 7.2GW of wind generation capacity.

This latest survey by UK contractors Brown & May Marine Limited, Jubilee Fishing Company Limited and Hull-based Precision Marine Surveys Limited, marks the end of an enormous campaign to provide the data Forewind will require for its applications, and to develop appropriate mitigation strategies.

Since being awarded the rights to develop Dogger Bank in January 2010, Forewind has initiated a huge range of ornithological and marine mammal, geotechnical, geophysical, benthic and fish ecology surveys to understand and characterise the seabed, environment and marine conditions of the zone as part of its offshore assessment work.

The ornithology and marine mammal surveys comprised almost four years of boat-based surveys by Gardline Environmental, working out of Sunderland and other ports, covering more than 40,000 kilometres in transects while trained observers recorded their findings. They also included aerial bird surveys by HiDef Aerial Surveying, based in Cumbria, over a total of almost 160,000 kilometres, or nearly four times around the world, in transects, using a bank of four digital video cameras attached to the aircraft to record all objects within a wide swathe at the sea surface achieving up to 2cm resolution allowing identification of bird species.

The geophysical surveys by firms including Gardline Geosurvey Limited, headquartered in Norfolk, comprised three campaigns, covering more than 50,000 line kilometres and an area of 4,700 km2, while the geotechnical work has included 84 boreholes and 174 cone penetration tests over three separate offshore campaigns. There has also been a dedicated investigation of seismic anomalies and sophisticated geological modelling in association with the British Geological Survey and Norwegian Geotechnical Institute.

The fish ecology surveys have to date acquired more than 850 samples across the areas proposed for wind farm development, as well as nearly 300 samples from the project cable corridors, running from the Dogger Bank Zone to the UK shore. The techniques used included otter and beam trawls, sand eel dredges, shellfish potting, and trammel netting.

The benthic surveys have comprised more than 423 camera sites, 373 macrofaunal sampling sites, 72 chemical sampling sites on the zone itself and along the proposed cable routes. Contractors included Fugro EMU Limited, a UK firm based in Southampton and Titan Environmental Surveys Limited based out of Bridgend.

Forewind General Manager Lee Clarke said that combined, this is largest body of work of its kind undertaken for an offshore wind energy development. It will provide a wealth of data for not only Forewind’s development consent order applications, but for nature conservation organisations, other commercial bodies and statutory authorities in the UK and Europe.

“The survey work to date will provide the organization with virtually all the necessary data for the environmental impact assessments for three stages of development, each stage with two up to 1.2 gigawatt (GW) offshore wind farm projects.

“It is safe to say we have completed the most ambitious and extensive campaign of survey work ever undertaken to assess an area in readiness for the consent, construction and operations of any offshore wind development,” Dr Clarke said.

“This would not have been possible without the depth and breath of expertise provided by our numerous contractors who have operated in challenging conditions and within tight timeframes to deliver the necessary results.”

Forewind’s first stage of development, Dogger Bank Creyke Beck, is now in the pre-examination phase with the Planning Inspectorate, with the final consultation phase for its second stage of development – Dogger Bank Teesside A & B – due to start on November 4, 2013.

Press release, October 14, 2013; Image: forewind