The NEWGASMET expert group is evaluating the CEN/TC237 Gas meter standards for conformity with the Measuring Instruments Directive (MID) when using (partly) renewable (or non-conventional) gases which are defined as hydrogen, hydrogen and natural gas admixtures, biogas, biomethane, and syngas.
A key challenge in making the gas meter standards suitable for renewable (non-conventional) gas use is the proper definition of the test gases that can be used to show compliance with the MID. Existing definitions of gas compositions are dealt with by reference to the EN 437 “Test gases – Test pressures – Appliance categories” standard, however the listed gases are intended as test gases, not gases necessarily found in the network, and the choice as a reference in the metering standard was dictated more by historical reasons (as no other specifications were available) than for the proximity of the application (gas appliances).
With the rise of renewable (non-conventional) gases in the gas network, a need to update the gas composition scope of the gas meter standards was addressed by the expert group. From available literature, and after extensive and careful consideration in the expert group, a set of test gases was defined. This set refers to existing relevant gas composition standards
- EN 16723-1 Natural gas and biomethane for use in transport and biomethane for injection in the natural gas network – Part 1: Specifications for biomethane for injection in the natural gas network
- CEN/TR 17238: Proposed limit values for contaminants in biomethane based on health assessment criteria
The set of test gases is as follows:
NEWGASMET project partners and CEN/TC 237 working groups have started communications on potentially adopting this set of test gases into the scope of the gas meter standards to enable showing MID compliance for renewable gas use. Notable outcomes of the dialogue are that the CEN/TC237 excludes biogas from the scope due to its corrosive nature and high unpredictability of its composition that is likely to impact the gas networks. Further the CEN/TC 237 makes use of the term “non-conventional” gases defined as fuel gases that are not defined as natural gas in EN ISO 14532:2017. The dialogue will be continued as the project progresses.