Power-to-gas technology plays a key role in the success of the energy transformation. This paper addresses issues related to the legal and technical regulations specifying the rules for adding hydrogen to the natural gas network. The main issue reviewed is the effects of the addition of hydrogen to natural gas on the durability of diaphragm gas meters. The possibility of adding hydrogen to the gas network requires confirmation of whether, within the expected hydrogen concentrations, long-term operation of gas meters will be ensured without compromising their metrological properties and operational safety. Methods for testing the durability of gas meters applied at test benches and sample results of durability tests of gas meters are presented. Based on these results, a metrological and statistical analysis was carried out to establish whether the addition of hydrogen affects the durability of gas meters over time. The most important conclusion resulting from the conducted study indicates that, for the tested gas meter specimens, there was no significant metrological difference between the obtained changes of errors of indications after testing the durability of gas meters with varying hydrogen content (from 0% to 15%).

Hydrogen is increasingly receiving a primary role as an energy vector in ensuring the achievement of the European decarbonization goals by 2050. In fact, Hydrogen could be produced also by electrolysis of water using renewable sources, such as photovoltaic and wind power, being able to perform the energy storage function, as well as through injection into natural gas infrastructures. However, hydrogen injection directly impacts thermodynamic properties of the gas itself, such as density, calorific value, Wobbe index, sound speed, etc. Consequently, this practice leads to changes in metrological behavior, especially in terms of volume and gas quality measurements. In this paper, the authors present an overview on the impact of hydrogen injection in natural gas measurements. In particular, the changes in thermodynamic properties of the gas mixtures with different H₂ contents have been evaluated and the effects on the accuracy of volume conversion at standard conditions have been investigated both on the theoretical point of view and experimentally. To this end, the authors present and discuss the effect of H₂ injection in gas networks on static ultrasonic domestic gas meters, both from a theoretical and an experimental point of view. Experimental tests demonstrated that ultrasonic gas meters are not significantly affected by H₂ injection up to about 10%.

Gas billing is always accompanied by unaccounted-for gas loss (UAG) which must be taken into account by gas operators. Gas theft is one of the sources of UAG in the gas distribution area and can be as high as several percent of revenues from gas supplies. The operator should have effective tools to prevent theft, both by detecting and combatting it. Gas companies try to prevent and detect gas theft using various methods. One of them is the continuous control of gas consumption at individual gas consumption points. The gas operator can thus minimize gas losses due to the use of faulty gas meters and gas losses due to leaks caused by third parties. The use of wireless communication technology in measuring devices and the connection of gas meters in smart networks enables the monitoring of gas meters and dynamic data transfer from the measuring devices. Any unauthorized interference with the gas network, gas installation or measurement system may pose a threat to human life and health, and illegal consumption of gaseous fuel is prohibited and is subject to criminal enforcement. The issues of illegal gas consumption have been defined in Polish law, first of all in the Energy Law, and in regulations concerning inspections by energy companies, on determining the scope and amount of fees for illegal consumption of gaseous fuels, and on detailed conditions for the operation of the gas system. The most widely used gas meter for measuring the volume of gas consumed in households is the diaphragm gas meter, which is usually equipped with a mechanical index, but in recent times the use of an electronic index has become more and more popular. The publication specifies several basic types of interference with household diaphragm gas meters, including the measurement system, the index, through the interaction with neodymium magnets, as well as by bypassing the measuring device. The most common are interventions by damaging the security seals and disassembling the gas meter index, followed by a change of indication or tampering resulting in false readings. It has been pointed out that the basic factor for limiting illegal gas consumption as a result of manipulation with the measuring device is ensuring the proper construction of gas meters, including equipping the gas meters with an electronic index with remote communication.