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Last updated on February 23, 2021

The Technology Readiness Level (TRL) scale was introduced into the EU funded projects arena in 2014 as part of the Horizon 2020 framework program. If you are planning to submit a Horizon Europe project proposal, even more so if your project is technology oriented – this article is for you. It is important to understand the exact implications of this scale on your project and the ways it is used to present, evaluate and measure the progress of a Horizon Europe or ERC project. In this article, we will discuss exactly that. Let’s start by understanding the fundamentals of the TRL scale and how it works.


What is the TRL Scale?

The Technology Readiness Level (TRL) scale was originally defined by NASA in the 1990’s as a means for measuring or indicating the maturity of a given technology. The TRL spans over nine levels as follows:

  • TRL 1 – Basic principles observed
  • TRL 2 – Technology concept formulated
  • TRL 3 – Experimental proof of concept
  • TRL 4 – Technology validated in lab
  • TRL 5 – Technology validated in relevant environment (industrially relevant environment in the case of key enabling technologies)
  • TRL 6 – Technology demonstrated in relevant environment (industrially relevant environment in the case of key enabling technologies)
  • TRL 7 – System prototype demonstration in operational environment
  • TRL 8 – System complete and qualified
  • TRL 9 – Actual system proven in operational environment (competitive manufacturing in the case of key enabling technologies; or in space)


Typically, many products go through the various stages of the TRL scale in their life cycle. It is possible that iterations will be needed between various TRL levels, especially during the development phase, although not limited to that. The TRL is perceived as an effective way to indicate the development stage of a given technology or product.


What does the TRL scale have to do with Horizon Europe project proposals?

Horizon Europe has selected the TRL scale as an indicator to better position the requested projects in the program (as expressed in the Horizon Europe annual work programs). The TRL, as a unified scale, enables applicants and reviewers to align with the expectations of the EC in this context. For example: a higher TRL in the call text clearly means that the EC is looking for a more applicative solution in the scope of the project. Alternatively,  a lower TRL in the call text indicates an expectation for a more basic research project, and so on…


Another use of the TRL is an indication of the ‘entry point’. This refers to the maturity level of the given technology/product/process at the beginning of the project. In this case, a given TRL serves as a ‘lower boundary’. Similar to the above, it helps in meeting the expectations of the EC in a specific call. For example: in the SME Instrument and in the Fast Track to Innovation (FTI), the entry point must be TRL 6 (System/ subsystem model or prototype demonstration in a relevant environment). Simply put – this means the funding scheme is not appropriate for R&D-intensive projects, typical of products positioned in lower TRL levels. Rather, it is more appropriate for mature projects with higher probability of getting to the market. In contrast, many other funding schemes rather support R&D-intensive projects, whether they specifically state a TRL level in the call for proposals or not.


At the time of proposal writing, one should try to evaluate the TRL of the technology/service/solution to be developed in the project. If the call for proposals specifically states an entry point or a goal for the end of the project – this is crucial. However, even when it is not specifically stated, this is a tool you can use to your advantage. Use it when describing your project, planning good milestones, and setting specific evaluation measures for progress. Keep in mind that the reviewers are asked to assess these issues. It is in your interest to ease the evaluation process and give the reviewers good answers to these questions.


Since the TRL scale is self-declared, it is important to remember that definitions of the various stages are quite general. Transitions between them can be a bit elusive. Indeed, this makes the process of assigning TRL to a given product not easy. Furthermore, comparing TRL across disciplines may prove almost impossible. Nevertheless, this needs to be done by applicants and reviewers alike. If issues arise in this context, it can prove helpful to seek assistance to solidify your proposal.


Tools for TRL assessment and declaration

The TRL assessment process begins with a meticulous check of the various TRL levels and definitions. The TRL scale for Horizon Europe is defined in Annex G of the Grant Agreement, as presented above.


Although it may look less relevant, we recommend also consulting with the US DoD TRL definitions, and NASA TRL definitions. This is because the origin of the TRL scale is in NASA. Both NASA and the DoD TRL definitions are more elaborate than the Horizon Europe TRL definitions. As such they shed more light on each level and its specific definition.


In addition, there are several tools that were developed in order to asses the TRL of a specific project or product. These can be found online:

  • The US Air Force Research Laboratory has developed a “TRL Calculator” which can assist in the process of evaluating the TRL of your project/product.
  • Another “TRL Calculator” was developed by the New York State Energy Research and Development Authority (NYSERDA).


ERC and the TRL Scale

As mentioned above, TRL serves as a reference to the development level of a specific technology. This starts from the basic principle research, continues to stages of development, and ends up with market outreach.


How relevant is this to ERC?

The answer is – not very much. This is because ERC focuses on basic high-risk research. ERC is not looking for applicative projects that may end up with technological proof of concept. In some cases, an ERC project may lay the foundations for a future technology, but the technology itself will be developed beyond the scope of the ERC project, in other funding schemes such as EIC Pathfinder (previously FET-Open).


If one insists on associating the ERC with the TRL scale, the reference should be not more than TRL 1. In fact, it should be TRL 0, but this level does not exist in the TRL scale…


To conclude, the TRL scale is a complex scale comprised of several definitions and implications. In the context of Horizon Europe, it is imperative to fully understand the varying stages, and exactly how to use it for your specific project proposal. For ERC, TRL is less relevant. Nonetheless, it is important to become fully aware of this in order to know how to best construct your grant proposal within the relevant grant requirements. For any assistance, please do not hesitate to review our selection of services.

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