Growth through Research, development & demonstration in Offshore Wind

Technology readiness levels

Technology readiness levels (TRLs) are a classification method for describing the maturity of technologies. The TRLs are used to indicate specific phases of innovation and the degree of development of a technology. Where TRL 1 stands for technology at the start of development and TRL 9 for technology that is technically and commercially ready.

The 9 Technology readiness levels

The European Commission has established the definitions of the levels as follows:


TRL 1: Basic principles observed

This phase is characterised by fundamental research. The basic principles of the technology have been observed and there are assumptions about the working principles of this technology. However, no experimental evidence for this is yet available.

TRL 2: Technology concept formulated

The technological concept and the possible field(s) of application have been formulated.

TRL 3: Experimental proof of concept

The first laboratory tests or analytical studies have been completed with a "proof of concept" as a result.

Technical development

TRL 4: Technology validated in lab

The proof of concept has been validated in a laboratory environment, often using raw (low-fidelity) small-scale prototypes: basic components are integrated to evaluate how they work together.

TRL 5: Technology validated in relevant environment

The technology has been tested and validated in a relevant environment. Functional and refined (high-fidelity) prototypes are often used for this.

TRL 6: Technology demonstrated in relevant environment

The operation of the technology has been demonstrated in a relevant environment. The prototype's performance has not yet been optimised for the operational environment.


TRL 7: System prototype demonstration in operational environment

The technology is integrated into the final operational environment. The prototype is (near) an actual operating system. The focus is now on  improving production design, certification, et cetera.

TRL 8: System complete and qualified

The technology is performing properly and the latest production problems have been solved.


TRL 9: Actual system proven in operational environment

The technology is technically and commercially ready. The next steps are production and market introduction.