This report presents the outcomes of a collaborative effort under the MetCCUS project to advance traceable
flow measurement for gaseous carbon dioxide (CO₂) in Carbon Capture and Storage (CCS) systems. To
support accurate and harmonised CO₂ flow metering, the project upgraded calibration infrastructure and
carried out coordinated inter-laboratory comparisons across major European metrology institutes. Key activities included testing various flow meter technologies (Coriolis, turbine, Ultrasonic, rotary) at both large and intermediate flow scales, assessing calibration transferability from alternative gases such as nitrogen and natural gas.
The results confirmed agreement across facilities and demonstrated the feasibility of using substitute gases
when appropriate considerations and corrections are applied. However, limitations were identified in Critical
Flow Nozzles performance with CO₂ and in turbine meter accuracy at low flow rates, highlighting areas for
further investigation.
