EU energy roadmap require an immediate change of direction toward green energy transition and energy independence. However, new solutions must face techno-economic, normative barriers that could negatively impact social acceptance. Green hydrogen (H2) is a crucial element as an alternative fuel to decarbonize EU and to decouple intermittent renewable energy generation and demand while ensuring electric grid stability. H2 blending in existing gas infrastructure can play a central role in unlocking the green transition since i) no extensive investment would be required, ii) large H2 volumes can be transported over long distances, and gas cross-border transmission capacities are significantly high, improving countries' renewable energy exports/imports. To date, H2 blending is limited also due to uncertainties on the impact of new mixtures on the already installed devices in the gas value chain such as measuring ones. Dedicated tests could answer the question. However, the normative framework, including testing methodologies for Hydrogen and Natural Gas (H2NG) mixtures, is still under-construction.
Validated protocols are required to define the H2 limits and tolerances of the measuring devices installed in the NG grids. While international roadmaps focus on pure H2 or repurposed grids, the regulatory framework lacks the protocols and the methodology to be adopted to approve devices that could operate in different H2NG mixtures or pure H2. To date, the NewGasMet project proposed a set of test gas definitions to cover the gaps of EN437:2018.
About distribution, domestic gas meters, were and are going to be experimentally tested. However, while tests up to 20%vol in stationary conditions have been completed, some other aspects are still to be clarified. Due to the challenging operative conditions (pressure and flowrate in the order of tens of bar and thousands of Sm3/h), methodologies, recommendations, and guidelines on how to design and operate H2NG “big loop” testing facilities are still missed. The proposal for new and/or updating standards is therefore very challenging.
THOTH2 aims to cover the normative and standards gaps relating to methodologies and protocols for evaluating the performances and identifying the limits and the tolerances of State of the Art (SoA) measuring devices in transmission and distribution systems when carrying H2NG mixtures or pure H2. Therefore, THOTH2 will design dedicated methodologies to test different types of measuring devices installed in the gas transmission and distribution grids. THOTH2 results will be helpful to provide recommendations to the Technical Committees (TC) of International Standard Bodies, to Gas Transmission and Distribution Operators (TSOs, DSOs), to measuring devices’ manufacturers, and to calibration service providers.
