The technology qualification wind turbine blades over 100 m will need: an FMECA-based plan

The technology qualification wind turbine blades over 100 m now need

The paper, Technology qualification plan for very large wind turbine blades, was published open access in Energy Reports, volume 16, in September 2026. Its starting point is commercial as much as technical: new manufacturers and design concepts, many from outside Europe, have shortened development cycles, and turbines are bid into projects while still being finalised and before they have a track record. Less time is left for validation just as validation gets harder.

That is the new turbine platform risk in one sentence. A blade over 100 m is not a scaled copy of a 70 m blade. It is relatively lighter and more slender than simple scaling would give, so it is more flexible; its tip speed is higher; and its laminates are thicker and its bond lines longer. In our reading, the margins a smaller blade enjoyed, between its natural modes and the rotor harmonics and between its flutter speed and its tip speed, shrink as a result. Failure mechanisms that were minor at smaller scale become dominant, and some appear for the first time. The paper's answer is a systematic, risk-driven technology qualification: identify what can fail, rank it, and plan the evidence that shows each critical mode is under control before the blade is committed.

We describe the paper here at the level of its published abstract.

What is a design FMEA, and what does FMECA add?

A failure modes and effects analysis asks, for every element of a product, how it can fail, what happens when it does, and how bad that is. The governing standard, IEC 60812:2018, describes FMEA as a systematic method for "identifying modes of failure together with their effects" and applies to hardware, software and processes alike. FMECA is the same analysis with a criticality ranking added, so that the modes which matter most rise to the top.

The conventional ranking multiplies three scores. In the textbook description by Menčík in Concise Reliability for Engineers, each failure mode receives a severity, an occurrence and a detection score, each from 1 (best case) to 10 (worst case), and their product is the risk priority number. IEC 60812:2018 also allows alternative calculations and a criticality matrix, which matters for blades because occurrence data for a structure never yet built is thin.

Why a blade DFMEA suits a blade that does not yet exist

Menčík separates product FMEA (the design FMEA, or DFMEA, of engineering practice), which asks "How can the product fail?", from process FMEA, which asks how a manufacturing step can harm the product, and stresses that the analysis belongs as early as the design stage. A design failure mode and effects analysis blade engineers can run before the first laminate is laid works from design intent: functions, load paths, materials, joints and interfaces, and it needs drawings and experienced people, not field statistics. A blade DFMEA is therefore the right tool for a next-generation blade: it can be applied while the design is still open, and it makes the lack of field data visible, because a mode with no proven means of detection scores badly on that axis. In our reading, the FMECA wind turbine blade designers need at this scale starts as a design one, with the process analysis following once the manufacturing route is fixed.

What is DNV-RP-A203 technology qualification?

DNV-RP-A203 is DNV's recommended practice for qualifying technology that existing standards do not fully cover. DNV's technology qualification flyer defines it as the process of providing evidence that a technology will "function within specified limits with an acceptable level of confidence". DNV also offers it as a service alongside certification for cases the existing rules do not cover (DNV technology qualification).

The flyer lays out the process as six steps:

1. Qualification basis: set the requirements, the intended use and the performance expected.
2. Technology assessment: establish the degree of novelty and any prohibitive obstacles, including the technology elements involved and their readiness levels.
3. Threat assessment: identify the failure modes and their risks, using methods such as FMECA.
4. Qualification plan: select the qualification methods that address each risk.
5. Execution of the plan: collect the evidence.
6. Performance assessment: verify that the evidence meets the requirements, or modify and repeat.

The technology assessment forces an honest answer to what is new: a material, a structural concept, a length class, or a known element in a new service context. The threat assessment is where the FMECA sits: the failure modes it ranks become the items the qualification plan must close, giving traceability from requirement to failure mode to evidence.

Blade certification does not disappear in this picture. It evaluates a design against published standards and remains the formal gate; technology qualification fills the space those standards were not written for. The paper's aim, as its abstract puts it, is faster and safer certification of next-generation rotor technologies; in our reading that is support for certification, not a way round it.

Which blade failure modes does the paper flag, and which are scale-induced?

The paper's abstract names five areas of particular focus: leading edge erosion, spar cap failure, adhesive debonding, lightning damage, and aeroelastic and flow-induced instabilities. It says the analysis covers conventional and scale-induced failure modes and ties every mode rated high or very high risk to a qualification activity. The table gives our own reading, as blade engineers, of why scale changes each mode and what evidence to ask about; it is not the paper's mapping.

The first four are known from smaller blades; scale shrinks their margins. The last grows with size: on a 100 m blade, the assumption that flap and torsion modes stay well separated and the flutter speed stays well above the operating tip speed is exactly what has to be qualified.

How does a blade qualification plan map risk to evidence?

The abstract describes the plan as linking every mode rated high or very high risk to a named activity, whether a simulation, a laboratory test, a field trial or monitoring in service, so that the route from risk to evidence becomes what the authors call a "traceable risk mitigation pathway". Each activity answers a different question:

• Simulation shows what the design is expected to do and where its margins lie, before hardware exists.
• Laboratory testing, from coupons and sub-components to full-scale blade tests, shows what the built structure does under defined loads.
• Field trials show how a measured prototype behaves in the environment the model simplified.
• In-service monitoring shows whether the first serial units behave as the prototype did.

The point of a blade qualification plan is not to do everything. It is to spend the effort where the ranking says the risk is, and to state, for each such risk, which activity produces the evidence that closes it and what result counts as closure. A list of activities not linked to ranked failure modes is a test programme, not a qualification plan.

What aerospace, offshore energy and nuclear practice add

The abstract says the authors drew on qualification practice in aerospace, offshore energy and the nuclear sector. Those sectors long ago accepted the position wind is now in: products too large, costly or safety-critical to learn about by fielding them. Their common discipline is to plan evidence against identified failure modes before the product exists, and to record and monitor the residual risk carried into service.

What should an owner, insurer or lender ask a manufacturer for?

If a bid rests on a blade that is still being qualified, the buyer is taking part of the qualification risk whether or not the contract says so. These documents, or the reasons for not having them, tell you how much:

1. The qualification basis: what the blade must do, in what environment, for how long, and against which standards.
2. The technology assessment: which elements are new relative to the manufacturer's previous blades, and the technology readiness wind turbine buyers are being asked to accept for each.
3. The FMECA register: the identified failure modes, their ratings, and which are classed as high or very high risk.
4. The qualification plan: for each high-risk mode, the activity that addresses it, its status and the acceptance criterion.
5. The test evidence: what the full-scale and sub-component tests were designed to demonstrate, and whether the tested configuration is the one being sold.
6. The residual risk: which modes rely on field trials or in-service monitoring rather than completed tests, and how the warranty, serial defect and monitoring terms carry that risk.

A manufacturer with a real technology qualification behind a new platform can produce these quickly. Where they are not available, the gap itself is the finding, and it belongs in the risk register or the contract.

Frequently asked questions

Does technology qualification of wind turbine blades replace certification?

No. Certification evaluates a design against published standards and remains the formal gate for a blade type. DNV describes technology qualification as a complementary service for cases where existing standards and rules are incomplete, and the paper's aim is to help new rotor technologies reach certification sooner and more safely. The technology qualification wind turbine blades over 100 m need therefore sits alongside certification, not in place of it.

Why does a design FMEA suit a blade that does not yet exist?

A design FMEA asks how the product can fail and works from the design intent, so it can be run before the blade exists. A process FMEA asks how a manufacturing step can harm the product; for a new blade it is run on the planned laminate, infusion and bonding route before series production, and it feeds the qualification plan with process trials, inspection coverage and acceptance criteria. The design FMEA comes first because it shapes the plan while the design is still open.

What makes a failure mode scale-induced?

A scale-induced failure mode is one whose likelihood or severity grows with blade length and turbine rating, or which appears only at large scale. The higher tip speeds chosen for large offshore rotors, thicker laminates, longer bond lines, greater lightning exposure and lower natural frequencies are the usual drivers, and aeroelastic instability is the clearest example.

Is Apex Wind independent of the parties named on the paper?

Yes. The paper is open access, and it lists its four authors, as printed, with affiliations at DTU Wind and Energy Systems (Kolios and Dimitrov) and TotalEnergies OneTech (Fajar and Capaldo). Apex Wind is independent of every turbine and blade manufacturer, sells no repairs, hardware, sensors or monitoring products, and takes no referral fees, so our reading of a qualification plan is not a route to selling anything.

How Apex Wind can help

Very large wind turbine blades reach a project as a set of documents long before they reach it as hardware, and the question for an owner or lender is whether those documents show a qualified design or a promised one. Our blade technical due diligence reads a manufacturer's qualification basis, FMECA and test evidence for what they show about a new platform, and states which risks belong in the price, the contract or the monitoring plan. For manufacturers and developers, our blade design and structural assessment work includes independent review of a design FMEA and of the evidence a qualification plan and certification will require. If you are evaluating a turbine that is still being qualified, contact us.