G-tec successfully completes Calvados Offshore Wind Farm UXO detection and identification campaign

G-tec has successfully completed the UXO detection and clearance campaign for the Calvados offshore wind farm in France. In total more than 2,200 km was surveyed.

Calvados offshore wind farm will consist of 64 wind turbines with a total installed capacity of ~450 MW, enough to supply electricity to 630,000 people. Commissioning is scheduled for 2024.

Calvados offshore wind farm awarded the two-phase contract in August 2021. First, a geophysical survey was conducted from the survey vessel ‘Geofocus’, and this included seabed mapping using a Multibeam Echosounder and Side Scan Sonar, as well as UXO detection using the state-of-the-art MagWing 6.8.

Significant cost reduction

MagWing 6.8 is the latest addition to the G-tec developed gradiometer frames for Unexploded Ordnance detection. The 6 m-wide frame features 8 magnetometers arranged in multiple vertical and horizontal gradients and is actively steered by the Scanfish ROTV. This combination delivers excellent stability, line keeping and a constant altitude above the seabed, which leads to unrivalled data quality, high production rates, a major reduction in the need for infill lines and above all, a substantial reduction in the number of false positives, leading to a significant cost reduction in the identification and clearance phases.

Three UXO’s identified

After cross-evaluation of the multi-sensor datasets, combined with historical and site data, the number of anomalies has been significantly reduced to few UXO-like targets during a collaborative iterative process by a joint team of experts from our client, G-tec and our Explosive Ordnance Disposal (EOD) partner Geomines.  Those UXO-like targets were then visually inspected by a robust ROV spread and identified by the EOD experts aboard. The campaign resulted in the identification of three actual UXOs, which were reported to the French authorities for safe disposal.

Ultimately, this campaign has ensured that the area is safe once construction operations start at the wind farm location.