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Addressing the Challenges of Wind Turbine Blade Inspection

Thu, 05 November, 2020

TWI is currently engaged in the SheaRIOS project, a Horizon 2020 research and innovation programme funded by the EU, to improve the efficiency and safety of wind turbine blade inspection, whilst reducing the associated costs. The SheaRIOS Project is developing a robotic on-blade inspection solution using shearography to assess the blade for wear and damage.

By their very nature of being located at remote locations in windy areas, wind turbines are continually subjected to large environment forces. The blades are particularly prone to strain and can fail without warning which has led to strict maintenance and inspection regulations. Based on a review of onshore and offshore wind farm regulations, standards and inspection practices a US government report published in 2015 (“Offshore Wind Energy Inspection Procedure Assessment”) recommended that the wind blades should be inspected every year. Despite regular inspections 85% of blade failures are as a result of poor maintenance. These failures are extremely costly, ranging from €90,000 to €900,000 (with the highest reported failure costing €5.5M).

More efficient and possibly more frequent inspections combined with preventative maintenance and are needed to reduce these costly failures. However, inspections require long downtimes with the wind turbines blades needing to be dismantled for ground inspections. Even when the blades are manually inspected using rope access trained inspectors, the blades need to be stopped for an average 4 to 6 days.

Downtime of the wind turbines results in loss of earnings for the operators but more crucially manual inspections at height are dangerous and can lead to accidents causing injury or death. In last decade there has been 249 accidents resulting in 161 fatalities associated with manual turbine inspections. It is estimated that these figures amount to just a portion of the actual number of accidents that occur and will only increase as the number of inspections increases.

In the EU alone, during 2012 there was a short fall of 5,500 trained technicians to conduct manual turbine inspections and this figure expected to rise to 28,000 by 2030. In the UK, a recent report by the Energy and Utility Skills Group estimates that there will need to be 36,000 people employed in offshore wind by 2032, which is equivalent to 260% more than in 2018.

One solution that has been investigated is the use of remotely operated vehicles (ROVs) to reach the blades requiring inspection. However, the current ROV systems are not very agile and are also unable to get close enough to the blades to effect a high quality NDT inspection. While these ROVs are acceptable for visual inspection purposes, there is still a real need to find an integrated solution that offers high quality inspection without endangering life. The need for an effective, remote inspection solution becomes increasingly pressing as wind power becomes ever more important for meeting our environmentally friendly power generation needs.

Techniques such as visual thermography, acoustic emission and ultrasound have been trialled for wind turbine blade inspection but all of them have been found to have drawbacks. For example, Acoustic Emission is an appropriate monitoring technology to detect defects but is unable to effectively size the defects. The SheaRIOS project has developed the use of Shearography, deployed via a specially designed remote controlled robot, to provide an efficient commercially viable system that reduces cost and most importantly improves safety.

You can find out more about the project at the dedicated website, here.


This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 780662 – H2020-ICT-2017-1

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