A European energy company, Vattenfall, successfully conducted large-scale seabed surveys with uncrewed surface vessels. The surveys were conducted in the late summer and early autumn of this year at several of Vattenfall’s offshore wind farms in Denmark, Sweden, and the UK.
When operating an offshore wind farm, it is necessary to periodically survey the seabed around turbine foundations and substation jacket legs to monitor changes in cable burial depth and scour development. The information is also important for repair and maintenance activities involving jack-up vessels – a stable seabed is needed to ensure the wind farm is located at a safe elevation out of the water.
Traditionally, crewed vessels carry out seabed surveys. However, these vessels emit substantial amounts of carbon from the consumption of fuel. When looking for a contractor for seabed surveys across its Danish wind farms, Vattenfall received an interesting proposal using uncrewed vessels.
“Having observed their deployment in small-scale trials elsewhere, we were curious to understand how successful their deployment would be on a larger scale,” says Rasmus Juncher, Senior Lead Geophysicist at Vattenfall. “This technology consumes much less fuel than a traditional survey vessel, and because the vessel is controlled from an onshore operations center instead of having a crew onboard, personnel aren’t exposed to the same challenges as working offshore, thereby improving safety and wellbeing.”
The uncrewed survey vessel is significantly smaller than a traditional vessel – it has a total length of 4.5 m (15 feet). This helps it reduce fuel consumption by up to 90% in some cases. However, the main reason for the big fuel saving is that they are more modern.
“This is the first step of many using uncrewed vessels, supporting the aims of a fossil-free future. We want to pursue further opportunities to support other functionalities of the uncrewed vessels, for instance, for visual inspections of our assets both above and below water and in-site investigations on a broader scale to support the wind farm design. The journey of autonomous vehicles, in general, has just begun, and I believe that the possibilities are endless. I am proud that Vattenfall is part of the journey. This is only the very beginning,” says Rasmus Juncher.
The service was provided by ocean data acquisition company XOCEAN, which has used uncrewed survey services since 2019.
“Our uncrewed survey vessel platform offers a safe, reliable, and low-carbon solution for the collection of ocean data. We are delighted to be supporting Vattenfall through the provision of sustainable data to support their survey requirements across the development and operation of their offshore wind farms,” says James Ives, CEO of XOCEAN.