ABSTRACT

The Dogger Bank zone is the largest of the Round 3 offshore wind zones extending over ~8660km2. It is located between 125km and 290km northeast of Yorkshire on the Dogger Bank, a topographic high point in the middle of the North Sea, with water depths of 18–63m. The sheer size of this zone is considerably greater than that of standard shallow-water oil and gas site investigations, leading to the generation of extremely large data volumes to manage, interpret and move between partners. This paper outlines the methodologies that Forewind, a consortium of energy companies, is utilising to prepare for the zone's development. This includes activities undertaken to date to develop a 3D model of the geology, stratigraphy and geotechnical conditions to assist in optimal selection of wind turbine foundations, both location and type. Survey programmes and preliminary results also are presented and discussed, illustrating experiences with ultra-high resolution multichannel sparker, shallow gas, glacial tectonics and fractured clays.

1. Introduction

In June 2008, the Crown Estate announced the opening of nine development zones within UK waters for offshore wind farm leasing, with a combined target energy output of 25GW. In January 2010, the successful ‘bidders’ for each development zone were announced, and Forewind Ltd - a consortium comprising Statoil, Statkraft, Scottish and Southern Energy (SSE), and RWE npower renewable - was awarded the development rights for Dogger Bank. Forewind is committed to securing the necessary Zone Appraisal and Planning (ZAP) consents for construction and development of the Dogger Bank zone. To achieve this end, Forewind has developed an intensive programme of geophysical, geological, geotechnical, metocean, biological and archaeological surveying which will encompass the entire zone (8660km2), undertaken in four tranches.

2. Regional Setting

Dogger Bank exists as an isolated topographic high point in the centre of the North Sea (Figure 1a).

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