Key comparison of gravimetric standards for hydrogen refuelling stations

Abstract

There are currently several mobile gravimetric standards for testing and calibrating hydrogen refuelling stations in operation. These standards are compliant for fuel delivery to light-duty vehicles according to the SAE J2601 protocol and provide measurement uncertainties that are low enough to use them for type-approval testing according to OMIL R139 recommendation. An international field comparison under real conditions is required to ensure a complete acceptance of test results by operators and notified bodies. In this paper, we will present details on a currently running comparison to settle this issue, and how it differs from standard comparisons. Specific strategies had to be adopted to make the experimental results consistent and comparable. The refuelling operating conditions can affect the outcome from the comparison and need to be taken into account. All these points are being addressed in this paper and are part of the comparison protocol. The aim is that in the end, based on the comparison results and the applied strategy, participants will be able to declare certified measurement capabilities to the BIPM.