Hydrogen has emerged as a required fuel and commodity needed for the decarbonization of the generation, distribution, storage, and energy consumption. Through the EU Hydrogen Strategy, the EC recognised the important role of hydrogen, and the need for the hydrogen market to be significantly scaled up. The boost in hydrogen production and its introduction in the energy market has arised one important issue: leakage of hydrogen during its storage, transportation and distribution. This leakage produces two negative side effects: there is a safety issue derived from the hydrogens broad flammability range (4 to 74% concentration in air) and it contributes to a net emmission of greenhouse gases (GHG) by depleting hydroxyl radicals (OH), thus increasing the atmosperic lifetime of methane and influencing tropospheric ozone formation, with an estimate accumulation effect of 5.8% increase over 100 years. The Green2TSO-OPTHYCS project will aim to develop new sensor technologies for continuous leak detectors based on optical fibre sensors technologies which will lead to an increase in the safety level of hydrogen applications, from production to storage and distribution, both in new infrastructure, working with pure H2, and in natural gas repurposed installations and pipelines, contributing to a safe and economically viable implementation of H2 production, transport, and storage processes. OPHTYCS project is built upon 3 conceptual areas: A) Technology pillars analysis and definition of new sensor technology , B) Validation of key use cases (pipelines, HRS and midstream sites (compression , metering stations, etc.) of the new technologies in 3 different controlled validation sites, and C) Aspects of the technologies derived from the use cases, including the assessment of the security and environmental risks evaluations and regulatory framework, and a scalability and cost efficiency study.

Green hydrogen is gaining moment across Europe as feedstock, fuel or energy carrier and storage, as solid actions are needed to reach carbon neutrality by 2050. Hydrogen has many possible applications across industry, transport, energy and building sectors and, therefore, local gas grids across Europe are working hard to get ready for its transport. The realization of the prospects of delivering H2/NG admixtures or even 100 % H2 by existing gas distribution grids exacerbates the problem of pipe integrity due to the well-known negative impact of hydrogen on the mechanical properties of metals. Most projects assessing safe hydrogen compatibility with natural gas distribution grids (i.e. H21, HydePloy,etc.) have performed experiments to study the leakage ratio, emission potential and explosion severity of vintage components. However, long-term material integrity assessment replicating distribution grid operating conditions in testing platforms is still necessary. CANDHy will allow the possibility of testing relevant metallic materials, different from the well-studied steels, with a methodology involving simultaneous test in independent R&D platforms with a common methodology. This will allow to obtain trustful and reproducible results about hydrogen tolerance of materials that have not been considered in previous research but that are an essential part in in low-pressure gas grids. CANDHy project will enable hydrogen distribution in low pressure gas grids by consolidated and exhaustive scientific data, coupled with harmonized guidelines for non-steel metallic grid materials. At least five material grades of different families (such as cast iron, copper, brass, lead, aluminium), both new and vintage, will be fully documented, and the results will be publicly available for all stakeholders in a continuously updated database. Mechanical tests will base on static and dynamic conditions to assess hydrogen sensitivity following the most relevant current and updated standards

Transporting natural gas through pipelines has been shown to be safe and efficient for decades. However, decarbonizing the European industry and reducing carbon emissions will require a significant portion of the existing pipeline infrastructure to be used for transporting gaseous hydrogen under high pressure across the continent, from production sites to end users. The pipelines, originally designed for natural gas, are not considered H2-ready, and Transmission System Operators must demonstrate their compatibility with hydrogen. The existing standards, such as ASME B31.12, are often viewed as overly conservative and not conducive to the development of pure hydrogen networks. PilgrHYm is an ambitious R&D project that seeks to develop a pre-normative framework to support the development of a European standard. The project aims to conduct a comprehensive testing program on small-scale laboratory specimens, focusing on 8 base materials, 2 welds, and 2 heat-affected zones that are representative of the EU gas grids. These specimens will be selected after a thorough review by TSOs to address safety concerns, lack of regulations, codes, and standards, as well as research gaps related to the compatibility of current pipelines with hydrogen. PilgrHYm's ultimate goal is to provide quantified data on more than 70% of the EU grid and refine existing norms, codes, and standards by reducing over-conservatism and ensuring the safety and reliability of flaw assessment methodologies. The results of PilgrHYm will serve as the baseline for a harmonized European solution. This project represents a significant step forward in the development of a comprehensive European standard for transporting hydrogen through pipelines and will be instrumental in the successful decarbonization of the European industry and reducing carbon emissions.

How maximize hydrogen (H2) blending potential in natural gas (NG) networks, supporting European energy system decarbonisation? The answer lies in the need of a systemic, multi-disciplinary approach to make NG infrastructure resilient to the challenges of tomorrow. Industrial and research players’ competences are required. In this framework, THOTH2 consortium focuses on energy measurement value chain and instruments’ ability to accurately measure physical parameters of H2NG mixtures with increasing H2 percentages, up to 100%. Including gas TSOs, DSOs, metrological and research institutes and academia, THOTH2 consortium has all competences and skills to reach the goals of i) define standards to evaluate the metrological performances of measuring devices at different H2 blending rates (up to 100%), ii) verify safety and durability of the same devices, and iii) suggest future needs to overcome the observed barriers and limitations. SNAM competences in managing NG assets are essential for the coordination and synergic integration of the 14 partners, recognized as experts in NG and H2 industry (GRTGAZ, GAZ-SYSTEM, Enagás, INRETE), metrology (CESAME, INRIM, METAS), H2 blending technologies and measuring devices design, engineering, and R&D activities (UNIBO, INIG, FBK, ENEA, CSIRO). The communication and dissemination strategy by GERG will give visibility to project’s results, including contributions to Mission Innovation 2.0 and EURAMET projects. THOTH2 vision will lead to an acceleration towards H2 economy, contributing to REPowerEU and NextGeneration EU objectives. The project impact potential includes the establishment of a R&D Hub center, including THOTH2 partners and Advisory Board members, to translate into valuable results achieved by the project, aiming to i) the development/update of international standards, ii) foster innovation in the field of H2NG blending measuring devices, and iii) supporting H2 value chain development leveraging on the EU gas infrastructure

If the solution for integration of intermittent renewable sources to decarbonate the industry and mobility is hydrogen, for example with European Hydrogen Backbone initiative, large-scale storage of H2 technical feasibility and economic viability is still hampering wide EU market uptake. FrHyGe main goal is to demonstrate and qualify in industrial environment in France the injection and withdrawal of H2 in a current natural gas commercial storage site. But FrHyGe will also deliver the conversion process and up-scale strategies to foster EU replication of H2 storage in caverns, starting with an ongoing project in Germany to accelerate know-how transfer and economic viability. FrHyGe objectives are: • To develop and implement two conversion processes from natural gas or brine cavern to hydrogen storage • To demonstrate H2 storage and cyclability in a 3000 tons potential cavern with 100 cycles from 1h to 1 week • To study the local hydrogen value chain and the techno-economic impacts on local actors and to upscale and deploy H2 storage along European Hydrogen Backbone • To assess the risks and environmental impacts of H2 cyclic storage in salt caverns and provide guidelines for safety, regulation and normative adaptations in Europe FrHyGe will open a path towards a potential of commercial 38 ktons of H2 storage in several EU countries as soon as 2030, and up to 1.5 Mtons in 2050 through conversion and creation of caverns, leading to a CAPEX below 10 €/Kg of H2 stored. To succeed, FrHyGe gathers EU leading H2 industries and research centres, led by worldwide underground storage actor Storengy, willing to make happen large-scale and multi-site H2 storage in caverns.