Growth through Research, development & demonstration in Offshore Wind


Pathways for Remote Inspection & Asset Maintenance support by employing Cargo Drones (PRIMA CD)

Improving offshore wind farm operations by using cargo drones


The operations and maintenance of offshore wind farms contribute 20 to 25% of the levelised energy costs. Maintenance costs consist of inspection, repair, and replacement of parts. The costs include labour, logistics, and vessels needed to travel offshore. The standard practice is that technicians take tools and replacement parts required for the maintenance of wind turbines to the turbines. However, spare parts and/ or tools must be delivered with additional transport if they are unforeseen.

Wind farms located far offshore require long vessel transits, which can lead to a significant reduction in effective time spent on a wind turbine. Repairs, in particular, can, therefore, cause long-term, costly downtime for the turbines. Using cargo drones for these kind of operations can reduce the downtime of wind turbines, and also minimise the number of trips per ship which leads to reduction in CO2 emissions and other pollutants. Another use case is that cargo drones can pre-transfer spare parts and tools to the wind turbine nacelle, reducing the time and effort required by technicians to lift these goods to the platform and nacelle. This adds significant safety to the operations and also results in less downtime of the wind turbines, a key benefit for offshore wind farm maintenance.


The project aims to evaluate the impact of cargo drones to transfer tools and spare parts to wind farms for corrective and planned maintenance. The project identifies the functional, technical, and economic requirements for cargo drones.

The impact of using cargo drones will be quantified through simulations of the maintenance scenarios. This will be done using TNO's UWise O&M Planner tool. The scenarios will be compared against a reference scenario which considers conventional methods for transferring spare parts and tools. The parameters for the reference scenario will be set together with all partners. Two cases are planned to be simulated of which one case will cover the use of cargo drones for ad-hoc operations, e.g. for delivering missing tools. The other case concerns planned operations with cargo drones with an assumed lifting capacity of up to 200 kg.

The study evaluates the business case at a high level and identifies barriers and opportunities for the commercial application of cargo drones for logistics purposes. This will help wind farm operators and service providers focus on promising solutions for using drones for maintenance applications.

The analytical part will be supported by input from practical tests that Ampelmann will carry out. The main outcome of these tests is to better understand the time required to deploy the cargo drones, take-off, travel, and landing times, as well as the landing procedure on wind turbines. The tests will take place in both onshore and offshore wind farms. The cargo drones that will be used for these tests are:

The onshore tests will be conducted in Reusel, the Netherlands. The cargo drone will transfer tools from the base to the top of the nacelle.

The offshore test is proposed to be carried out at a Vattenfall wind farm. The offshore tests will be carried out in two phases. In the first phase, several flights will be performed in the wind farm to measure:

  1. Measure electromagnetic interference EMI around WTG,
  2. operational time required to land,
  3. optimise flight routes and approaches, and
  4. validate workability parameters.

In the second phase, we will perform a three- to five-day operation to validate the use case. In this test, we collect data on how a drone is used, track its weight and cargo type, and obtain operational feedback from the site team.


The project will deliver the following results:

Contact Details


Janaki Mohannair
+31 6 4803 8279

Technology Readiness Level

Maturity level: 4.
        4 5

Project duration



Other information

This project is supported with a subsidy by the Dutch Ministry of Economic Affairs and Climate Policy and TKI Offshore Energy.