Renewable Energy is a global requirement and increasing in demand due to decarbonisation and the need to reduce pollution generated from brown energy.

There were 341,320 wind turbines spinning around the world at the end of 2016, which equates to a capacity of 486.8GW globally. The total capacity at the end of 2019 is 651GW, an increase of 10% compared to 2018\. Although there is an increasing demand of wind turbines, market surveys show that current inspection methods are inadequate. Due to WTB's large size and stress caused by wind gusts, wear is fast, thus there is a regular need for inspection and maintenance.

There are a variety of inspection techniques that have been widely used in the wind industry, but few of them can be applied to inspect a wind turbine blade (WTB) onsite and in-situ. Ultrasonic testing is a pointwise contact inspection technique for homogeneous materials, thus is difficult to use to inspect the inhomogeneous composite material parts of a WTB on-site. Radiography has safety issues because of the use of radiation. Thermography is a promising NDT technique, but its capability of inspecting a WTB on-site is not proven, because the ambient temperature change due to wind flow will add strong noise to the captured thermal images. It is also highly susceptible to emissivity of the blade surface, which means any changes in emissivity caused by rain, snow and other contaminations will result in false alarms. The use of drones to inspect wind asset including WTBs is attracting more attention in recent years, however it is limited to visual inspection for surface defects only.

Shearography, as a non-contact inspection technique, is widely used to inspect various materials including composite in industry to identify subsurface defects. However, it requires a very stable working condition such as in a test lab or a test facility. The use of shearography in-situ for WTB inspection is not yet fully demonstrated, because WTBs are in constant vibration even when they are stopped for maintenance and inspection at good weather with low wind speed.

We have identified a way to address the stability problem for shearography by introducing a stabilising mechanism to the shearography so that it can work properly on a WTB in-situ. The ShearWin system will be the first shearography product in the world that allows human inspectors to deploy it on a WTB in-situ. A prototype system will be developed at the end of the project. With the technique protected by a patent (pending), the project consortium is confident that the innovative ShearWin product will be further developed into a commercial product to reach the wind energy service market within 1-2 years after the successful completion of this project.