Technology Readiness Level scale (European Commission, 2014)
| Maturity level | Description | Stages |
| TRL 1 | Basic principles observed | Ideas stages |
| TRL 2 | Technology concept formulated | |
| TRL 3 | Experimental proof of concept | Development stages |
| TRL 4 | Technology validated in lab | |
| TRL 5 | Technology validated in relevant environment | Validating and pilot testing stages |
| TRL 6 | Technology demonstrated in relevant environment | |
| TRL 7 | System prototype demonstration in operational environment | Demonstration in real world stages |
| TRL 8 | System complete and qualified | |
| TRL 9 | Actual system proven in operational environment |