Chemical sensing vs. Gas chromatography: Metrological characterization of two methods for hydrogen quantification in energy gas blends

Hydrogen is currently favoured as a replacement for natural gas in the decarbonisation of gas grids. In addition to pure hydrogen grids, blending with natural gas is also being discussed, but this is limited by infrastructure requirements. In any case, high-precision on-line analysis is required to measure the hydrogen amount for quality control and to ensure energy metering for billing purposes. The industry is therefore looking for suitable analysis methods. One way is to upgrade proven process gas chromatographs, another is to use new dedicated sensors. As part of the EMPIR-Decarb project, a first comparison of the accuracy of these systems was carried out using traceable calibration gases with small uncertainties. Two commercially available measurement systems show that comparable measurement uncertainties of about 0.5 % (k = 2) can be achieved in the range between 30 % and 100 % of hydrogen. In the case of the process gas chromatograph, linear behaviour can even be observed down to a hydrogen concentration of 1 %.