When applying technology readiness levels (TRLs) to assess technology maturity, the technology is evaluated against broad criteria for each level and assigned a TRL rating based on its stage of development.
There are nine TRLs, ranging from TRL 1 (Basic Research) to TRL 9 (Proven System Ready for Full Commercial Deployment).
Although there are various ways of defining and interpreting the criteria at each level, there tends to be general agreement that, depending on the market relevance and intended use of a particular technology, application of the ISO 14034 verification standard may be justifiable in the range of technology demonstration (TRL 6) through to full commercial deployment (TRL 9) - i.e.,
Initial scientific research conducted, focusing on fundamental understanding of materials and/or processes and new discovery.
Outcome: Principles qualitatively postulated, observed and reported.
The shift from TRL 1 to TRL 2 moves ideas from basic to applied research to confirm potential of material or process application to solve a problem or satisfy a need.
Outcome: Technology concept formulated, and initial practical applications identified.
At TRL 3 advanced applied research and early stage development are intended to confirm that the concept works as expected. Studies and laboratory measurements validate analytical predictions of separate components of the technology, with limited effort to integrate the components into a complete system. Modeling and simulation may be used to complement physical experiments.
Outcome: Confirmation of analytical and experimental critical function and proof-of-concept.
TRLs 4-6 represent the bridge from scientific research to engineering, and from development to demonstration. TRL 4 is the first step in narrowing possible options for the complete system and determining whether the individual components will work together. Design, development and lab testing of technological components/processes is undertaken to establish if they will work together.
Outcome: Evidence that performance targets may be attainable based on projected or modeled systems.
At TRL 5 the basic technological components are integrated so that the overall system configuration is similar to, or matches, the final application in most respects. The major difference between TRL 4 and 5 is the increased congruity of the system and its operating environment to the actual application. The basic technological components are integrated for testing in a simulated environment, such that the system tested is prototypical with test results that should be statistically relevant.
Outcome: System component and process validation achieved in a relevant simulated environment (i.e., beta prototype component level).
Engineering development of the technology as an operational system begins at TRL 6. The major difference between TRL 5 and 6 is the step up from laboratory scale to engineering scale and the determination of scaling factors that will enable design of the final system. The engineering pilot scale demonstration should be capable of performing all the functions that will be required of a fully manufactured system. The operating environment for the testing should closely represent the actual operating environment, with results that are statistically relevant. The goals while in TRL 6 are to reduce engineering risk and refine the cost model, representing a major step forward in demonstrating the readiness of the technology.
Outcome: System prototype or model demonstration in a simulated environment (i.e., beta prototype system level).
This represents a major step up from TRL 6, requiring demonstration of an actual system prototype in an operational environment. Final design is virtually complete. The goal of this stage is to remove engineering and manufacturing risk. To credibly achieve this goal and exit TRL 7, scale is required as many significant engineering and manufacturing issues can surface during the transition between TRL 6 and 7.
Outcome: Prototype demonstration in an appropriate operational environment (i.e., pre-commercial technology demonstration level).
At this TRL, the technology has been proven to work in its final form under expected conditions, which in most cases represents the end of system development. True manufacturing costs will be determined and plans to address performance gaps may be needed.
Outcome: Commercial system/process completed and qualified through testing and demonstration (i.e., commercial technology demonstration level).
At this level, the technology is in its final form, operated under a full range of real-life operating conditions, and ready for full commercial deployment This includes steady state manufacturing meeting cost, yield, and output targets, with emphasis shifting toward statistical process control and optimization.
Commercial system proven and fully deployed in operational environment (i.e., market deployment level).