In 2021, the primary focus in Europe was on the decarbonization of the natural gas network, but recent geopolitical developments (the war in in Ukraine) have shifted the priority to energy security. Many industrial consumers, mainly for security reasons, have invested in LPG-air mixing systems. All possible sources of natural gas are being activated, and regions that were previously supplied with a consistent calorific value of natural gas now face significant fluctuations. This is due to altered gas flows, where historic Russian gas flows to Western Europe are largely replaced by LNG flows from Western Europe to Eastern Europe. In Germany, transmission network operators informed their customers about changes in gas quality due to these altered flows, with substantial impacts in both the L-gas (Liquid gas such as LPG) and H-gas (Hydrogen gas) networks.

The initial LNG FSRU (Liquified Natural Gas Floating storage and regasification units) terminals have begun injecting large volumes of gas in the Netherlands and Germany, with additional terminals expected to start within the next two years—not only in Germany but also in Poland, France, Finland, Estonia, Italy, and Greece.  In South Africa new LNG Importation facilities are also planned to aid with the natural gas supply shortage from the Temane gas fields.

Nearly every EU country has defined or announced a hydrogen strategy. Massive subsidies are being provided to launch this industry. However, only a few small projects are currently operational, but the pace and volume of upcoming projects have increased dramatically. Combined biogas and biomethane production in Europe reached just over 200 TWh (719 Peta joule) in 2021, up from 191 TWh in 2020, according to preliminary estimates by the European Biogas Association (EBA). In the last 18 months, 300 new biomethane plants were commissioned, bringing the total to 1,023, with 87% connected to the gas network. The trend of increased feed-in continues, which means more rapid measurement methods are needed for control purposes.

It is clear that natural gas plays a crucial role in energy security. It is simply impossible to switch to other energy carriers overnight. The consumption of pure natural gas must increasingly be replaced by biomethane, green hydrogen, and synthetic gases. This shift also implies a more decentralized gas production setup, which is not the case with fossil natural gas. To increase the use of renewable gases, it is essential to maintain process safety in industry. Large fluctuations in calorific value over short time intervals demand quick calorific value measurement devices—not only at each network connection but wherever necessary to ensure process integrity. The costs for such a measurement station vary significantly, from cross-border stations where hundreds of thousands of m³/h pass through to industrial processes that consume around 400 m³/h. Nevertheless, measurement requirements are similar across many EU countries.  In South Africa continued measurement of the gas composition will also become mandatory with the injection of LNG and biomethane into the existing Sasol pipeline and gas network.

Correlative measurement systems offer a significant economic and technical advantage. Recent technological advancements allow correlative devices to measure with sufficient accuracy, much faster, and at only a fraction of the cost of process gas chromatography. The explosion-proof RGQ 5 gas quality analyzer by RMG uses correlative measurement principles. By combining a patented dynamic viscosity sensor with a thermal conductivity sensor, the stationary MEMS-based multiparameter gas analyzer RGQ 5 correlates these properties with parameters such as calorific value HS, heating value HI, Wobbe Index (WS & WI), density ρ, compressibility, air/fuel ratio λ, and methane number MN. Variants are also available that indicate hydrogen and CO2 concentrations in mol-%.

The RGQ 5 is likely the only device on the market that can output combustion properties like calorific value, relative density, and Wobbe index with an accuracy of ±1%, for gases with or without H2 content up to 30 mol%.

Designed specifically for plug-and-play operation, the analyzer requires no special knowledge or experience to operate. The device provides values every second via Modbus RTU (RS485) or through an analogue output (4–20 mA current loop), making it easy to integrate into plant control systems. Due to its short measurement cycle time, the RGQ 5 is highly suitable for control tasks, even in explosive environments. The RGQ 5 is already used today for continuous monitoring of gas quality in biogas engines, hydrogen blending facilities, combined natural gas/biogas burners, LPG-air mixing systems, biogas processing plants, and various synthetic gas applications. 

The following example illustrates the RGQ 5 in parallel operation with an EMC 500 (a discontinued correlative measurement system by RMG) and a process gas chromatograph (PGC 9304 by RMG) at a customer’s biogas processing facility, where it has been measuring for three months and actively controlling the calorific value. To obtain an optimal comparison, all three devices were set up in parallel. The proven EMC 500 (orange curve) traditionally led the control of the conditioning process.