The TRL (Technology Readiness Level) scale has become a widely used framework for measuring the maturity of a technology, from the initial idea through to operational deployment. Used in sectors as diverse as aerospace, defense, energy, and information technology, the TRL scale helps structure innovation initiatives, guide investments, and reduce risks in technology development. This guide offers an in-depth exploration of the TRL scale, from its origins to its practical applications, including its limitations and best practices.
The origins and evolution of the TRL scale
The TRL scale was developed in the 1970s by NASA to address a specific need: to objectively assess the maturity of technologies intended for space missions. At that time, the growing complexity of space projects called for a structured framework to mitigate technical risks and optimize resource allocation. The framework quickly proved useful beyond the space sector. Other industries facing similar innovation challenges have adopted the TRL scale.
Today, major institutions such as the European Commission use it to standardize the evaluation of technology projects, particularly within the framework of funding programs like Horizon Europe.
Initial objectives and adjustments
The fundamental purpose of the TRL scale is to provide a common, standardized language for describing the maturity level of a technology. This framework facilitates communication among researchers, engineers, decision-makers, and investors. Over time, the scale has been adapted to various sectors, with each sector incorporating its own specific characteristics. For example, in the healthcare sector, additional criteria related to clinical validation have been incorporated, while in the energy sector, the focus is on demonstrating performance under real-world operating conditions.
Detailed description of TRL levels
Description of the 9 levels
The TRL scale consists of nine levels, each corresponding to a key stage in technological development:
- TRL 1: Observation of basic principles.
Identification and examination of the fundamental scientific principles underlying the proposed technology.
- TRL 2: Formulation of the technological concept.
Formulation of the concept or potential application, based on the observed principles.
- TRL 3: Analytical and experimental proof of concept.
Initial validation of the concept through analytical studies and laboratory experiments.
- TRL 4: Laboratory validation.
Validation of the technology in a controlled laboratory environment using functional prototypes.
- TRL 5: Validation in a relevant environment.
Testing the prototype in an environment that simulates real-world conditions.
- TRL 6: Demonstration in a relevant environment.
Demonstration of the system or subsystem in a representative environment that closely resembles operational conditions.
- TRL 7: Demonstration in an operational environment.
Demonstration of the final prototype in a real-world operating environment.
- TRL 8: Fully developed and validated system.
The system is complete, validated, and ready for deployment.
- TRL 9: System operational in production.
The technology is fully operational and being used in actual production conditions.
Concrete examples for each level
To illustrate progress along the TRL scale, let’s take the example of developing a new environmental sensor.
- TRL 1: Basic research on the properties of a new pollution-sensitive material.
- TRL 2: Proposal for a sensor design utilizing this material.
- TRL 3: Conducting initial laboratory tests to verify the material's sensitivity.
- TRL 4: Development of a sensor prototype and validation of its performance in the laboratory.
- TRL 5: Testing the prototype in a climate chamber that simulates outdoor conditions.
- TRL 6: Installation of the sensor at a pilot site for an initial demonstration under real-world conditions.
- TRL 7: Deployment of the sensor at multiple operational sites to validate its robustness.
- TRL 8: Sensor certification and launch of industrial production.
- TRL 9: Marketing and use of the sensor by customers in real-world applications.
This model also applies to software development, where the process moves from defining algorithms (TRL 1–3) to validation using real-world datasets (TRL 5–7), and then to deployment (TRL 8–9).
Using the TRL scale in innovation management
Decision-making tool
The TRL scale is a valuable tool for project leaders and decision-makers. It helps structure the technology roadmap, identify critical milestones, and plan the resources needed for each stage.
For investors, the TRL provides a clear framework for assessing a technology’s market potential and the associated level of risk. For example, a technology at TRL 3 will still require significant R&D investment, whereas a technology at TRL 7 is close to commercialization.
Access to financing and grants
Many funding programs, particularly those at the European level, require proof of the TRL level for project eligibility. Horizon Europe calls for proposals, for example, often specify the expected TRL level at the start and end of the project. Project leaders must therefore provide detailed documentation demonstrating technological maturity (test reports, prototypes, field validation) in order to qualify for grants. This requirement promotes the transparency and credibility of the projects submitted.
Limitations and criticisms of the TRL scale
Despite its strengths, the TRL scale has certain limitations. It focuses exclusively on the technological aspect, without taking into account commercial, regulatory, or organizational factors. Thus, a technology can reach a high TRL without necessarily being ready to capture the market, due to the lack of a viable business model or regulatory compliance. Furthermore, assessing the TRL can sometimes be subjective, which is why rigorous documentation is so important.
Application example: the Poclain Hydraulics case
As a recognized industry leader in the field of hydrostatic transmissions, Poclain Hydraulics uses the TRL scale to manage its advanced engineering studies and ensure a smooth transition from research to development.
To learn how Poclain Hydraulics structures its advanced research using the TRL scale and the IDhall platform, read their testimonial.
Best practices for using the TRL scale
Rigorous and well-documented evaluation
To ensure the reliability of the TRL assessment, it is essential to rely on concrete evidence at every stage: test results, test reports, prototypes, external validations. This documentation facilitates communication with partners, funders, and regulatory authorities.
Integration with other assessment tools
The TRL scale should be used in conjunction with other assessment tools, such as risk matrices, market analyses, or regulatory feasibility studies. This comprehensive approach makes it possible to anticipate non-technical obstacles and maximize the project’s chances of success.
The TRL scale has established itself as a key tool for structuring, managing, and supporting the successful development of technological innovation projects. By providing a standardized framework, it facilitates communication among the various stakeholders in innovation and promotes access to funding. However, to maximize its effectiveness, it is essential to integrate it into a comprehensive approach that takes into account all aspects of the project: technological, commercial, regulatory, and organizational. This will enable companies and project leaders to better navigate the complex landscape of innovation and turn their ideas into tangible successes.
FAQ – The Technology Readiness Level Scale
What is the TRL scale?
The TRL (Technology Readiness Level) scale is a universal tool, originally developed by NASA, that makes it possible to objectively measure a technology’s maturity, from the initial concept through to industrial production.
What are the different TRL levels used for?
The 9 TRL levels describe the successive stages of technology development, from the scientific principle (TRL 1) to commercialization (TRL 9). Each level helps pinpoint the progress of a project.
In which sectors is the TRL scale used?
The TRL scale is used in many fields, including aerospace, energy, healthcare, and information technology. It is also frequently required in funding applications (e.g., Horizon Europe).
How do you classify a technology on the TRL scale?
It is recommended to rely on concrete evidence (test results, prototypes, validations) to determine the TRL level achieved. The assessment should be as objective as possible.
Does the TRL scale take market or regulatory factors into account?
No, the TRL scale focuses solely on technological maturity. It does not cover market, regulatory, or organizational aspects, which must be assessed separately.
What are the benefits of the TRL scale for project management?
The TRL helps structure the innovation roadmap, plan resources, identify critical milestones, and effectively communicate the project’s progress.
What are the limitations of the TRL scale?
The assessment may involve some degree of subjectivity and does not cover all aspects necessary for a project’s success (market, regulations, organization).
How to complete the TRL analysis?
It is advisable to supplement the TRL analysis with other tools—such as risk matrices, market studies, and regulatory analyses—to gain a comprehensive understanding of the project.
Why is the TRL scale important for funding innovation?
Many public and private funders require a TRL assessment to ensure that the technology is sufficiently mature before investing.
