Wind turbine blade inspections with the Elios 3

Discover how the Elios 3 was used to demonstrate the value of a drone wind turbine blade inspection, providing results in 1 day instead of 5!

Benefits In A Nutshell

According to the Global Wind Energy Council, there are over 341,000 wind turbines installed across the planet. These giant structures are incredibly effective, with the average wind turbine from 2020 capable of creating enough energy to power a household for 1 month in just 46 minutes. 

However, maintenance challenges for wind turbines are substantial. Wind turbines are very high up in confined spaces. To access one, you must have specialized training from the Global Wind Organization to learn how to move in and out of turbines, rappel out safely, and what to do in an emergency. Between the challenges of working at height, in confined spaces, and the need for tailored training, it can be challenging to find inspection staff for wind turbines. 

Why use drones for a wind turbine inspection? 

In February 2024, Swedish service provider Drone Solution partnered with a wind turbine management company to test if it would be possible to inspect the inside of wind turbines with drones. Drone Solution already used drones to inspect the external elements of wind turbines, but the internal process had not been done with drones before. Drone Solution are one of the few drone operators in the world capable of this. 

The sheer size of wind turbines makes them difficult to inspect

Inspections for wind turbines are principally focused on detecting either manufacturing faults or lightning damage. When lightning strikes a wind turbine blade there may only be a small mark on the outside. The inside, however, may have significant damage that puts the turbine at risk. In some cases, the blade may explode if a lightning strike makes contact with grease or oil within the turbine, which can happen if the lightning defenses (sometimes called a Lightning Protection System) are not properly configured or have previously been damaged. Regular maintenance and inspections can help prevent problems before they occur, especially when a destroyed wind turbine blade can cost $1 million to repair. Wind turbines are incredibly costly to build, with it costing $1 million per megawatt (eg a turbine generating 4.6 megawatt would cost around $4.6 million to build). These high costs make it imperative for effective inspections to mitigate problems. 

Drone Solution uses drones for various challenging inspections, including confined space inspections with the Elios 3. They wanted to demonstrate the value of a drone wind turbine blade inspection to show how the internal and external infrastructure could all be inspected with drones - and that it would be faster and safer than traditional methods.

Planning to inspect a wind turbine blade with the Elios 3

Wind turbines have 3 blades, each of which needs to be individually inspected. To inspect the internal elements, it requires a person to undergo confined space training. This is because the blade tapers to a narrower point at the end, often starting around 2 meters wide and gradually getting narrower to the point of being less than a meter in diameter. Not only this but the blade is split into sections by structures that run the length of the blade called shear webs. This means that an inspection is not a simple up-and-down approach, but requires multiple inspections of the same distance within the same blade. When a person completes the inspection, each blade being inspected needs to be pitched horizontally so that a person can crawl up one side, and then once that is completed, the blade must be rotated to the other horizontally to inspect the other side of the shear webs. Overall, the traditional inspection process with people completing the visual inspection is slow, requires highly specialized staff, and can be very costly. 

As a result, the inspection process for wind turbine blades can be slow and painful. Inspections of an entire wind turbine can take 5 to 9 days depending on the size of the blade. Drone Solution wanted to see how much faster it would be with the Elios 3. 

The process: a drone wind turbine blade inspection 

The wind turbine being used for the demonstration has blades that are 67 meters long. To access the blades, the Drone Solution inspectors had previously completed their wind turbine training. Then at the site, they took a 20-minute elevator up to the wind turbine’s hub, where the access hatches were for each blade. They programmed the turbine to pitch 2 blades upwards, at positions matching 10 and 2 on a clock. These upturned angles were important so that in case there was a problem with the drone, it would roll safely back down rather than being stuck and someone having to go and get it. 

The Elios 3 outside of an access hatch on a turbine 

The Elios 3 was flown into each blade and along either side of the shear webs over 30 meters up the structure. During this, the pilot used the 4K camera to gather visual data and take photos of potential problems as well as suspected lightning damage. The space was gradually getting narrower, and to help navigate, the pilot used the FlyAware live LiDAR scan to help orient themselves in the space when the drone was beyond the line of sight. The LiDAR point cloud also helped the pilot determine how far they had flown into the blade. The entire space that required inspection was covered in just 27 minutes - 3 flights with the Elios 3. Then, the pilot moved on to the next step. The process and positioning of the blades were repeated for each blade. 

After inspecting inside the blades, the Drone Solution team used a separate drone to fly around the outside of the wind turbine. 

Snapshot: the Elios 3 flying inside a turbine blade with the shear web on the left

Results of a drone wind turbine blade inspection 

Both Drone Solution and their client were blown away by the results of using the Elios 3 drone for the blade inspection. The visual data from the Elios 3 showed damage inside the blade that was not visible externally and also not easy to access. This immediately proved the value of using the drone compared to traditional methods. 

Typically, this type of inspection would require 2 people in the hub with highly specialized training. The work at height and in confined spaces can be a barrier to some, so it was ideal to be able to use the drone instead and only need 1 person in the space. In addition, the Elios 3 could inspect each blade in 30 minutes. This is much faster than traditional methods where an individual blade may take over a day, or with rovers. Rovers require a blade to be pitched horizontally, like with inspections by people, and take 2 hours per half of the blade (totaling 4 hours per blade). 

Thanks to using the Elios 3, Drone Solution demonstrated that it would be much faster for turbine managers to use drone wind turbine blade inspections instead of traditional manned methods. The safety, speed, and data quality improvements all combined to present a realistic and better alternative. Following this success, Drone Solution and their client hope to be able to convince the turbine owners to authorize further drone inspections at more turbines and wind farms, unlocking a new and regular type of mission for Drone Solution.