By Janaki Mohanan Nair, TNO
As offshore wind farms expand and move farther from shore, efficient logistics are critical to maintaining operations addressing the challenges of supply chain constraints, skilled labor shortages and vessel limitations. Unmanned aerial vehicles (UAVs) are transforming offshore wind logistics by enabling rapid delivery of tools and spare parts. This streamlines workflows, enhances technician safety, minimizes downtime and supports a more cost-effective and sustainable renewable energy future.
Traditionally, missing tools or parts require costly, time-consuming ad hoc trips via crew transfer vessels (CTVs) or service operation vessels (SOVs). Additionally, transferring tools from vessels to transition piece and further to nacelle increases safety risks and inefficiencies. UAVs provide an alternative by conducting ad hoc trips and also pre-loading tools and parts directly onto the nacelle, thus reducing vessel transits and improving safety.
UAV deployment simulations for cargo deliveries
Ampelmann, TNO and Vattenfall, under the umbrella of GROW and TKI, launched an initiative to explore UAV use for transporting tools and spare parts weighing below 200 kg. The study analyzed various operational scenarios using TNO’s discrete event simulation logistics tool, UWiSE, to assess UAV effectiveness in both minor corrective and scheduled maintenance operations.
In cases where technicians, arriving via CTVs, require forgotten or missing tools (up to 40 kg) UAVs can provide minor corrective repairs and troubleshooting activities, typically lasting up to four hours. The study also evaluated the benefits of pre/de-loading tools via UAVs.
In addition, a scheduled maintenance scenario focuses on three-day annual maintenance campaigns per turbine, incorporating UAVs for both ad hoc deliveries and pre-/de-loading of essential tools.
The simulations conducted by TNO consider that a total time savings of 2.1 hours is achieved during each maintenance visit. This is based on two factors: first, a time savings of 1 hour is realized through pre/de-loading using UAVs; second, an additional 1.1 hours is saved on average by utilizing UAVs for ad hoc deliveries. These combined savings are compared to the baseline scenario where conventional CTVs are used. The reduction in time spent on maintenance activities leads to multiple benefits, including lower fuel consumption due to reduced vessel operation, a corresponding decrease in CO2 emissions and an overall increase in the uptime of wind farms, as maintenance tasks are completed more efficiently.
Successful UAV trials in the North Sea
To validate the study’s parameters, field trials were conducted at Vattenfall’s DanTysk and Sandbank wind farms in the German North Sea. UAVs operated by Ampelmann successfully delivered cargo to wind turbines, completing flights between the Acta Centaurus SOV and turbines within a 5 km radius.
Despite winter conditions, the UAVs performed effectively in moderate sea states with wave heights of 1.5 m and wind speeds of 5 m/s. The workability of the UAVs were observed to be higher and better than that of the CTVs. Deliveries were completed in five to nine minutes depending on the distance, an improvement over the 1-hour duration required by CTVs. The trials underscored the importance of risk assessments, HSE evaluations and seamless integration of UAV operations into SOV workflows.
Expanding UAV capabilities beyond cargo deliveries
UAVs have the potential to revolutionize offshore operations beyond logistics. With enhanced payload capacities and longer battery life, they could be pivotal in emergency and rescue missions. To fully unlock their potential, UAVs must integrate advanced sensor technologies and rely on robust offshore connectivity. Additionally, combining cargo deliveries with wind turbine inspections presents a powerful use case, further improving operational efficiency. This integration could significantly reduce downtime and maximize wind farm output—if supported by comprehensive feasibility studies as well as rigorous risk and safety assessments.
The adoption of UAVs in offshore wind farm logistics represents a paradigm shift toward automation. By reducing dependency on vessels, lowering operational costs and enhancing safety, UAVs are set to become a critical asset in the offshore wind sector. As the industry continues to evolve, embracing such innovative technologies will be key to ensuring a more reliable, cost-effective and environmentally friendly energy future.
