In the late summer and early autumn of 2022, Swedish energy company Vattenfall conducted large-scale seabed surveys with uncrewed surface vessels. The surveys were conducted at several of Vattenfall’s offshore wind farms in Denmark, Sweden, and the UK.
Part of operating an offshore wind farm is periodically surveying the seabed around turbine foundations and substation jacket legs to monitor changes in cable burial depth and scour development. This knowledge is important for repair and maintenance activities involving jackup vessels, where legs require a stable seabed to ensure safe elevation out of the water.
Traditionally, seabed surveys have been conducted using crewed vessels, which emit substantial amounts of carbon from the consumption of fuel.
“When we issued the tender to select a contractor for seabed surveys across our Danish wind farms, we received an interesting proposal using uncrewed vessels,” said says Rasmus Juncher, Vattenfall’s senior lead geophysicist. “Having observed their deployment in small-scale trials elsewhere, we were curious to understand how successful their deployment would be on a larger scale. 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 vessel is significantly smaller (4.5 m total length) than crewed vessels and typically also more modern, which explains the fuel savings.
Vattenfall said it aims to expand the use of uncrewed vessel in future operations. “This is the first step of many using uncrewed vessels, supporting the aims of a fossil free future,” Juncher said. “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 have just begun, and I believe that the possibilities are endless.”
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,” said James Ives, CEO of XOCEAN. “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 windfarms.”