EME 807
Technologies for Sustainability Systems

2.2 Technology readiness levels (TRL)


Technology readiness assessment is a systematic, metrics-based process that evaluates the maturity of, and the risk associated with, critical technologies under development. It is a commonly accepted approach used in a number of industry and government organizations to assess the maturity of a technology (e.g., device, material, component, process, etc.) on an entire scale - from its invention to commercialization and wide-scale application. TRL rating actually determines how far a particular technology is from being deployed by industry or public. That, in turn, determines the amount of resources - time, funds, intellectual potential, facilities, etc., - necessary to bring this technology to life. We can illustrate the term 'readiness' with a simple example like the one below.


For example, I am a researcher at a National Lab working on a small-size methanol fuel cell - a device that can convert the chemical energy of the fuel (methanol in this case) to electricity. I have my fuel cell stack operating in the lab and producing some great data in terms of power density. “It really works!” – I think. But can I put that fuel cell stack on my bike and have a ride home? Well... not right away, at least. The fuel cell system, the way it is set up and operates in the lab, is not ready for immediate use on a bike. I can possibly spend a few more months to work on the adaptation – fixing the fuel cell system on a bike, attaching an electric motor that would transfer the electrical power from the cell stack to the wheel, finding the regulators that would allow me to control the output during a ride, figuring out the position of the methanol fuel source and lines connecting it to the cell… it is quite an engineering project.

But let us imagine that finally I make it work! But can I offer this technology to bikers around town? I used my special knowledge to make all the technical adaptations and to solve multiple challenges, fixing shortcomings. If something is wrong, I know where to find a problem. But a general biker would not like to do all the work I have done and learn all the details I have learned. They would like it simple and fool-proof. I think, the technology, again, is not ready for public yet at that point. And, again, more resources and time are needed to make it user-friendly and more reliable for marketing.

Addendum: I worked on the methanol fuel cell systems in 2001. Years after some companies (Yamaha is one of them) actually managed to create some slick prototypes of fuel cell scooters, like the one shown here. However, it is unclear if any of those made it to the market. If you find any information or references to it, please let me know!

There are many other examples of technology going through many years of adaptation prior to reaching its broad applicability. What you see in the left-side image below may seem like a hardly recognizable mechanical device. What is on the right side is its contemporary version. The first computer mouse prototype was invented in 1964 by Douglas Engelbart of Stanford Research Institute. The mouse device remained an subject for further development, modifications, demos, and pilot projects for two decades before it was finally adapted for broader use with the personal computer Mackintosh 128K in 1984 (Wikipedia)

First computer mouse: wooden shell, 2 wheels, cord, & plug. modern mouse with slim sleek outer plastic shell
Engelbart's first prototype of the computer mouse (1964) (left); modern look of the computer mouse (right). It took two decades for computer mouse to develop to reach the readiness level for broad adoption and use.

How do we evaluate the maturity or readiness of a particular technology?


Technology Readiness Level (TRL) scale was first employed by NASA in 1974 to evaluate the maturity of technologies for spacecraft design as part of risk assessment. It was demonstrated that transition of emerging technologies at lesser degrees of maturity results in higher overall risk.

Later, the TRL scale developed by NASA was also adopted in the U.S. by the Department of Defense (DOD), Department of Energy (DOE), Air Force, Oil and Gas Industry and also in Europe by the European Space Agency (ESA). The main rankings in the TRL method for technology readiness assessment are classified in the table below.

Stage of Development Technology Readiness Level Description Outcomes/Supporting Information
Table 2.2. TRL rankings and metrics for technology assessment as adapted from NASA and DOD practice
Basic technology research TRL0 Unproven idea No analysis/testing performed.

Basic Principles observed and reported

Scientific research begins to be translated into applied research and development.

Published research that identified the principles that underlie the concept.
Research to prove feasibility TRL2

Concept formulated

Practical application is invented based on TRL 1. Potential of the applications is speculative and is inferred from general assumptions or some analytical data.

Published research that outlines the application and initial analysis of underlying principles.


Analytical and experimental studies are performed on a lab scale to validate analytical predictions. Work is done on various components of the potential technology (which are not yet integrated).

Experimental data, measured parameters of interest in comparison with analytical predictions.

Lab-scale demonstration (“low fidelity”)

Basic technological components are integrated to establish that they will work together. This is relatively “low fidelity” compared with the eventual system.
Results of laboratory testing. Comparison with system performance goals.
Technology demonstration

Lab-scale demonstration (“high fidelity”)

The basic technological components are integrated with reasonably realistic supporting elements so they can be tested in a simulated environment.

Results of laboratory testing in simulated environment. Identified barriers for target performance goals and plans to overcome them.
System development TRL6

Prototype system designed

The system is integrated with support elements, and model design is created to be tested in simulated or operational environment.

Results of the prototype testing in simulated lab environment. Data are close to target expectations.

Prototype system tested in operational environment

Prototype near or at planned operational system. Represents a major step up from TRL 6 by requiring demonstration of an actual system prototype in an operational environment (e.g., in the field, on aircraft, in a vehicle, or in space).

Results of the prototype testing in operational environment demonstrate success.
System launch and operation TRL8

Actual system completed

The system is qualified through test and demonstration. Technology has been proven to work in its final form and under expected conditions.

Results of testing in its final configuration. Assessment of it meeting its operational requirements. Plans, options, or actions to tune and finalize the design.

Actual system proved successful

Actual application of the technology in its final form and under mission conditions or on market.

Reports on real application performance.

TRL approach proved to be useful as a tool for:

  • general understanding of technology status;
  • risk assessment and management;
  • decision making with respect to technology funding;
  • decision making with respect to technology transfer.

In the context of this course, it will be important to understand the technology readiness levels in order to properly assess the timeline and cost of its development and implementation. When applied to a particular technology, the above listed TRL ranks should be customized for better relevance. Such customization would identify specific milestones as criteria to advance to the next level.

Watch This!

Please watch this 15 minutes and 47 seconds video in which Dr. Sean McCarthy (Hyperion Ltd) elaborates on the TRL concept, provides some examples, and examines the ties of TRL assessment to the decision making and choosing partners for a project. This video is made in the context of the european innovation and technology implementation landscape, but many of those insights are completely transferable to the US soil as well.

Click here for a transcript of the Technology Readiness Level video.

In this module, we're going to look at the concept of technology readiness level. And at the bottom of the first slide, you can see a web link that we've made. so any of the links I mentioned in the presentation you'll find them on this particular webpage. So,first of all, I want to look at just a quick overview of technology readiness level to see what it is. Then I want to talk about technology readiness level in Horizon 2020 and how technology readiness level can be used when you're selecting partners for the project. And finally, in the impact section of your proposal, you'll see me repeating the use of TRL so I just introduced the concept of TRL an impact here.

Now, the organization called EARTO has written an excellent report on technology readiness level. EARTO is an organization representing over 350 of the top research and technology organizations in Europe and you can see their website on this webpage. Now the concept of technology readiness level originated in 1977 and the aerospace industry introduced it as a way of expressing the level at which technology was evolving. So, there are nine levels to it which I'm going to explain in the following slides. In the eighties, it was then adopted by the Aeronautics industry and then other industries like electronics and pharmaceutical industry started to adapt it for their own needs and today most industries use it. So, the concept of TRL is not a European Commission concept. It's concept of industry but it has now been brought into Horizon 2020 and we look at in module two.

Now, the concept of TRL one, which is the basic principles are observed, so this is obviously the whole territory of basic scientists where's TRL nine means the product is ready to go on the market. So, in this presentation I’m going to use a computer mouse as an example of how you know how TRL can explain the evolution of the computer mouse. So initially the concept, somebody had this concept, that you can you move an icon across the computer screen and the technology concept was formulated. Somebody tried to decide how it will be done so this is TRL two. TRL three is laboratory experimentation, and you expect an experiment with many many different concepts, and you look at different concepts and you prove them but TRL four means it's working at laboratory level. So, let's have a look at TRL four mouse. So here is the official photograph of the first mouse. You can see it's made of wood. It's probably very heavy and probably if you move that, an item moved across the screen so it was pretty fundamental you couldn't sell this thing. And the 1984, I found this quotation that one of the top computer people in America said, that they didn't think that this will have much of the future. Now TRL five is where the technology is validated in a relevant environment, so it's tested but it's not power to the environment. TRL 6, it means it's demonstrated in a relevant environment, again it's not part of the system but it's being demonstrated. Now here in TRL seven it's demonstrated, and the key word here is in an operational environment, so it goes into a real system. Now in TRL 8, it means the system is working and the new component is integrated into the system. So, it's completed and here you could be looking at meeting standards meeting regulations and so on. And, in the TRL nine, the product is on the market. So, Logitech, which is one of the biggest producers of the mouse and it's said in their website that they've shipped over 500 million mice and that only represents about half of all the mice shipped over the last 20 years. So, it's an example of how technologies evolve.

Now, if you look at the pharmaceutical industry, that whole chain could be twenty years. If you look at the software industry, that chain could be 18 months. In energy, it might be 78 years from initial concept to having something on the market and, it varies between technologies, so TRL 1 to TRL 9 is a way of expressing the level at which your technology is at any moment. Now, this slide shows the more common terminology where basic research, laboratory research, technology research, technology demonstration, so those terms are sometimes used, and it just puts them in the position of the TRL table. Now, if we also look at the biotechnology sector and on the art or document, they discuss this comparison. So, you can see that phase one trials is about TRL 5 6. Phase two trials is TRL 7 and so on. Now, in Horizon 2020, they've adopted TRL as a way of expressing and where a folding scheme is focusing and what they've actually published is a general annex and annex G of the general annex on the participant portal contains the definition of the TRL and it is actually in the definition I have used in the previous section of the presentation and section one. Now, here's an example of a topic in column number one of Horizon 2020. So, we can see here it's NMP 1 2014 and we can see here that implementation of the proposed is intended to start at TRL 4 and target here at TRL 6. So, it means that the funding is focusing on projects that operate in this area. So, it's not funding basic science. It's not from the close to the market and it's telling the scientists so we're looking at technologies that have been developed in the laboratory. We want to focus on demonstration prototyping and so on. Of course, if you look at another program the transport program under aviation, and we can see the Caesar joint undertaking is focusing on TRL from one to six. That means in their ethics part of the program they've got from basic research basic concepts right up to demonstration and prototyping and so on. So, that's how would you see TRL appearing and TRL is mainly mentioned in pillar 2 which is industry leadership. Now on pillar three, which is societal challenges, they don't mention TRL too often but you have to use the same concepts when you're explaining and what lived in your project is focusing.

Now let's look at this diagram again. This zone, let's call it, these TRL's are referred to as the value of debt now academic researchers don't like TRL 5 6 & 7 basically because there's no publications in either. Industry doesn't like 5 6 & 7 because it's very expensive and it's very very risky. Now framework 7 the previous European program came to about TRL 4. But horizon 2020 is going to TRL 7. So, that's why Horizon 2020 is called a research and innovation program. Now there's a problem with their funding schemes. When national and European bodies are designing funding programs, they have to take into account that are called European competition law and international state aid rules. Basically, what they say is that the Irish government cannot fund a company to make it more competitive than a German company or an American company. So, these are very very strict rules. So, when funding bodies are designing their programs, they are restricted by competition law and stated rules to focus on approximately up to TRL 7. So that's why if Horizon 2020 is called a pre-competitive research program. So, let's look at the different programs in horizon 2020 and see where they're actually located. Now national funding goes from TRL 1 from the basic science up to demonstration and prototyping and programs like Eurostar's which is for research intensive companies bringing things close as close up in the market. That's about TRL four, five, and six. ERC phones frontier our basic research and that's roughly TRL 1 going into TRL 2. Fed future and emerging technologies is roughly TRL 2. Now, pillar two and pillar three stretch from TRL 2 up to about the end of TRL 6. Now, public-private partnerships, this is where European, national, and private funding is put on the table. Now, when your private funding put on the table, that means you can go further than the competition losses because industry is putting money on the table. but you can see the public-private partnerships are focusing on TRL 5 plus. Marie Curie fellowships they fund postdoctoral research but they also fund things like industrial PhD’s, the rise program for staff exchange between academia and industry. So, some of them are equally programs are focusing on the development of skills for people dealing with industry.

EIT, European Institute of Innovation and Technology is trying to position itself across the valley of death and accessing finance is about funding high-growth companies at TRL 6 plus. It's also used for other applications but, in the case of enterprises, it's for funding this part of the program. So, you can see here, how all the different programs and how they're related. Now, as you go towards TRL one, the main evaluation criteria becomes excellent scientific excellence. As you move in the direction of TRL four five six, the main evaluation criteria becomes impact. So, if you're at TRL, say, 2 to 4, then you have to consider both excellence and impact. Now, the different grants in Horizon 2020 address different parts of the TRL chain. The ERC grants of course are forming the ERC program. Now, in such an innovation actions, these grants cover from about TRL 2 to about the end of TRL 4 or early TRL 5. innovation actions are focusing, and demonstration prototyping living labs and they normally cover about TRL five, six, and seven. The SME instrument is mainly TRL 5 plus. So, it's looking at bringing technologies closer and closer to the market and the new type of grant fast-track to innovation is also focusing on TRL 5 plus. The public procurement, this is where public bodies demand innovation or research, that's actually getting closer at to the market. Now, coordination and support actions, these fund studies therefore networks and if cover the full range of TRL 1 to TRL 9 but it's mainly studies dealing with these particular areas.

Now, let's see how a TRL can be used when you're selecting partners for your project. The universities and research centers public research centers normally operate in the range of TRL 1 to TRL 4. Some of the research centers like Max Planck in Germany they would be operating at TRL 1 and 2. A lot of universities, you know, might be more basic research, which are TRL 1 and 2, where some research centers would be at TRL 3 or 4, but generally the public research centers are in this range. Research and technology organizations operate from about TRL 4, you know, up to TRL 7. and again, this is where EARTO, the European Association of research and Technology Organization tries to operate. So, it's getting closer to the market so it's working with universities and research centers but doing things that are more relevant to the needs of Industry. Research intensive companies now these could be big companies fairly large companies that have research departments, or they could be spin-off companies from research centers where, you know, highly qualified researchers set up their own company. They can bring results, you know, from TRL 5 onwards. Whereas, high tech companies, these are is that like to have technologies verified demonstrated piloted, and again they are normally operate maybe around TRL 7 or 8. So, when you're selecting your partners, you can see that for TRL 1 & 2 we are seeing fit, it's more suited to universities. Whereas TRL 4 5 6 is more suitable to the research and technology organizations. Now impact. Impact is asking the question what is coming out of your project and who will use those results. Now, if you're looking at an ERC project, now this is fundamental research. So, if that's operating a TRL 1 then the people that are interested in those results is the scientific community. So, if you look at the evaluation of ERC, they talk about what is the research impact of the results.

Now, if you're operating in a research and innovation grant, which is operating TRL 2 to TRL 5, then obviously the people that are interested in these results are people operating at about TRL 6 and, in that case, it would be the research and technology organizations and research-intensive companies. However, if you're looking at things like innovation actions, which is at TRL 5 and 6, then the organization’s interested in these results would be high technology companies, standards organizations, and regulatory bodies. Now if you're looking at an SME instrument, then you're getting really close to the market and the lead users here would be the early adopters of new products, new services, and business models. So, when we look at the impact part of the proposal, you will see how we will use the TRL table and, I think what we've shown in this presentation is the concept of TRL is a very useful way of describing the programs, describing the grants, describing the role of the different partners, and describing the impact.

So, I hope you enjoyed the presentation and again you can look at this website. It's an open website and you can find all the links that I described in the presentation. So, thank you very much and I look forward to seeing you in the next in the next modules. Bye for now!

Assigning a TRL rank is not a quick task. These are some serious questions that need to be answered and backed by technical data regarding the current status of technology:

  • Is technology widely commercialized?
  • Is technology demonstrated in the final form (in a target system)?
  • Is technology demonstration in the relevant environment (field conditions)?
  • What is the target performance / efficiency level (technically and economically)?
  • What is currently achieved performance / efficiency?
  • What are the materials involved and what is their availability?
  • Is infrastructure available for deployment for this technology?
  • What are the main barriers impeding the higher performance? … etc.

You can see that determining the status of technology development often requires search and knowledge of most recent advances, publications, and news releases on the technical performance, demonstration, pilot systems, and prototypes. It also requires independent expertise in subject matter along with understanding the economic criteria, which establish a threshold where the technology becomes economically feasible and is able to compete with existing alternatives.

What kind of data sources can you use for TRL analysis?

  • Scientific publications in refereed journals
  • Government agency reports
  • Company news releases (may withhold technical details that are proprietary)
  • Public news, web blogs, ads (secondary sources which may refer you to original information)
  • Personal communications with experts, researchers, and enterprenuers 

Try this tool!

Check out this TRL calculator tool, developed by the Advanced Energy Technology Group at University of California San Diego, which can be used to automatically retrieve the TRL value for a particular project based on input scoring on each level criteria. You are welcome to explore it and use it in your course project when determining TRL for the technology of your choice. (Note: the calculator is in MS Excel format. You must enable macros to make it work). This excel file is also available in Module 2 in Canvas. 

I hope you found content on this page useful. Different assignments in this course will tap into the TRL concept repeatedly, and you will be asked to either estimate the TRL ranking or provide some analysis of technology readiness and maturity in your course project. 

Answer this self-check question:

An R&D group in a company developed the design and built a prototype of a new car engine. It has been through a set of comprehensive lab tests, which provide excellent results in terms of system performance. What technology readiness level can be assigned to this development? Click on your answer below.


This would be too low - at this level, the key concept and applications are outlined.


This would be too low - at this level, system components are tested, but they are not yet integrated.


Correct! - at this level, system prototype is tested in the lab under simulated operational conditions.


This would be too high - at this level, the actual system (not prototype) is built and put in real-life operation (without commercialization).

TRL 10

This would be too high - Level 10 is not part of TRL scale but rather denotes commercialized technology.

Additional Resources on Technology Readiness Levels: