East Anglia ONE Offshore Wind Farm: Geotechnical Engineering

Project Summary
ScottishPower Renewables’ 714 MW East Anglia ONE offshore wind farm is Iberdrola’s largest wind farm, the project is situated 43km off the Suffolk coast and features 102 Siemens Gamesa SWT-7.0-154 wind turbines on jacket foundations. The export cables were 85km long and made landfall at Bawdsey where they were connected via an onshore cable route of 37 km to the Burstall sub-station.

East Anglia ONE is a joint venture between ScottishPower Renewables and Macquarie’s Green Investment Group (GIG), and was a £2.5 billion project and the first of the East Anglia R3 zone projects that ScottishPower Renewables is developing.

OWC’s Background on the project
OWC is proud of its history, adding value to the East Anglia ONE (EA ONE) project and our involvement with EA ONE goes back to 2013. OWC have since delivered work and completed numerous other roles on the project up, and are still adding value today.

Geotechnical and Structural Engineering
OWC delivered, as part of the work, an innovative approach to site investigation (SI), with a live SI campaign and ground modelling. Through innovative optimising of the SI, managing design and project risks, and ensuring boreholes were placed in areas of most uncertainty and to the correct depth, we saved EA ONE in excess of £4.0m – contributing to lowering the pre-FID spend.

OWC also assisted in the development of the foundation concept including drivability analysis, conceptual monopile and jacket design.

Cable Route Design
OWC conducted a cable burial risk assessment (CBRA) on the whole export cable route, considering a statistical analysis of vessel anchor sizes and likelihood of anchor-cable interaction.

We also carried out the site assessment of the proposed cable landing location, this included all directional boring or HDD points under the roads and rivers across East Anglia; from cable landing location to the grid connection at Bramford.