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Innovation Challenges

Internal Blade Structural Monitoring


Defects can occur throughout the composite material of a blade, not just on the visible surface.  Composites used for blades are formed by impregnating strong fibre reinforcements with resin.  The result is a very robust, erosion resistant material however the curing process can result in voids and air bubbles within the material, creating weak spots.  If these areas of weakness are not picked up in inspection, fatigue loading can lead to catastrophic blade failure on site.  Internal inspection is one method used to detect these flaws before they become critical.

External inspection is done by offshore operators using rope access and currently, that is also the method used for internal inspections.  Blades have a rigid balsa wood spar inside which provides structural integrity to the blade however this can cause problems for internal blade inspection, reducing accessibility and therefore the mobility of the operator.  The taper of the blade renders a length of blade towards the tip inaccessible and impossible to inspect.  There are also significant health and safety risks for operators inspecting blades offshore in these remote locations and dynamic offshore conditions.

An ideal method for internal blade inspection would reduce or remove the need for human intervention entirely.  This could take one of two approaches.  ROVs (crawling, flying etc.) or AUVs can be used to access the blade intermittently to inspect for cracks and defects.  Another option would be for the solution to remain permanently inside the blade, (cameras, sensors etc.), taking a condition monitoring approach to the problem.  Removing the need for rope access would eliminate the health and safety risks associated with it and has the potential to reduce offshore wind operation and maintenance costs.


The proposed solutions for this challenge must be deployable without requiring changes to existing manufacturing and design of offshore wind turbines.  To meet the desired timescale and risks, it is preferred that the proposed solution, or the key part(s) of the solution, has been commercially proven in other sectors.

Functional Requirements

  • Solutions should be capable of detecting, monitoring and acquiring data concerning the physical internal condition of an offshore wind turbine blade
  • Solutions must be deployed safely and ideally remotely to reduce human intervention.
  • Inspection must be undertaken in-situ with the blade being held stationary at various radial angles.
  • Solutions should reach restricted spaces for inspection beyond what can be achieved by a human operator.

Technical Characteristics

  • Solutions should be capable of detecting a minimum physical flaw/defect of 2mm, ideally to a depth of 20mm.  The flaws may include cracks or defects.
  • Structural defect data, such as measurements and images, must be provided in three dimensions to an accuracy of ±10cm.
  • Solutions deployed when needed will need to fit through an access hole of 50cm by 50cm.
  • Solutions should be able to inspect a cross-sectional area of 150m2 in 20 minutes or less.
  • Solutions that are permanently mounted to the structure will need to operate while experiencing motion fatigue and at G-force.

Deployment Timescale

  • Validation of solution: within 6 months
  • Field trials: within 1 year
  • Commercial implementation: within 1-2 years

Operating Conditions

  • Solutions must be able to be operated safely and reliably in offshore conditions of:
    • an ambient temperature -10 to 50°C (but to a minimum temperature of -30°C is preferred)
    • heights of 100-200m from sea-level
    • distances up to 100km from shore
  • Solutions will be able to access a 120V electrical supply and WiFi or LAN connections.
  • Device failure or loss within the blade must be minimised or eliminated.

Cost Requirements

  • New solutions must offer a faster inspection rate at a lower overall cost.  Current industry practice delivers inspection of 100m2 within 20 minutes at a cost of £7,500 per three structures.
  • An ideal solution should aim to cost approximately £10,000 or less and offer a speed improvement of at least 50%.
  • The current estimated UK market for retrofit of a successful solution will be in the region of £54m with a significant additional growth in domestic and export markets.

The estimated UK market for retrofit of a successful solution will be in the region of £54m, with a significant additional growth in domestic and export markets.


Turbines are increasing in size. Therefore, blades are getting longer and powertrain systems are increasing in capacity.

From 2010 to 2016, wind turbine power rating has grown by 60%. In 2017, the average capacity of new wind turbines installed was 5.9 MW, a significant increase from 3.0 MW in 2010, reflecting a period of continuous development.  The first 8MW turbines have been in operation since late 2016.

Offshore wind turbine blades tend to be between 50 and 88m long. Condition monitoring is becoming more critical as owner/operators look to improve their understanding of blade erosion and remedial repair requirements as the assets age.  The service and repair market for blades is experiencing rapid growth due to the accumulation effect of continual wind farm development and installation.

Market size

The blades and powertrains market has seen rapid growth following a sustained offshore wind build program in Europe led by the UK and Germany.  Europe has 4,149 offshore turbines installed and grid-connected as of January 2018 with a total capacity of 15.8 GW across 11 European countries.

Market Forecast

The 11 offshore projects under construction in Europe as of January 2018 will increase installed capacity by a further 2.9 GW, equating to around 800 new powertrain systems and 2400 new blades just for offshore wind alone.  In 2016 a total of 4,948MW of new capacity reached FID and it is projected that the total European installed capacity will reach 25 GW by 2020.

Do you have a potential solution?

The market potential is huge for solutions that offer a faster blade internal inspection rate at a lower overall cost.

Apply now

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