Deliverable 1.2: First version of the H2 releases' database

To date no inventory of hydrogen (H2) emissions occurring along the value chain exists. Otherwise, few data are publicly available. Due to its potential impact on Global Warming Potential, in recent years more attention was given to the estimation of H2 emission (Cooper et al., 2022; Derwent, 2023). Waiting for a conclusive answer about its impact on the atmosphere, some contributions appear in the literature providing some inputs (Arrigoni et al., 2024; Bond et al., 2011; Frazer-Nash Consultancy, 2022; Sand et al., 2023). However, due to the relevance of the topic, a rigorous approach defining how to collect data is needed as soon as possible. The NHyRA project aims to be the starting point. However, several considerations arose during the first six months of activity regarding the inventory design. First, the methodology accepted in the natural gas (NG) should be considered a first template for H2. Therefore, defining new terminology or emission classification would not be necessary. This choice could simplify any standardization activity. Three types of emissions, i.e., fugitives, vented, and incomplete combustion, were adopted. As for the NG case, sub-categories were also identified to ensure proper categorization. Secondly, the inventory has to be designed to collect data regarding the emissions from each archetype defined in Task 1.1. The data selection is of paramount importance to ensure a proper characterization of the emissions and allow for the achievement of other target activities by the interested end[1]users, such as scenario analysis and mitigation analysis. During the task activity, the discussion among the involved partners of the NHyRA project achieved an agreement to record the parameters that were considered relevant. Due to the high amount of information to be recorded, the NHyRA partners also agreed to develop this manual to explain the philosophy on which it is based on the inventory. Since it is expected to get new data during the NHyRA project and after its completion, rules have been defined to ensure the quality of the data to be inserted in the inventory. As reported the quality check will consist in a rigorous procedure ensuring the traceability of the source for future validation or replication especially in the case of experimental value. The NHyRA project partners identified some limitations of the present study to direct the research in the next months. First, the present version of the H2 inventory includes a limited amount of data for some of the archetypes in the H2 value chain section, including production, conversion, storage, transport, and end-uses. More data are needed to ensure consistent scenario analysis and provide mitigation action recommendations. The new inventory releases at M12 and M18 are expected to achieve the target. For this purpose, the literature review has to be improved. Second, the NG approach adopted in the present study relies not only on the direct measurement of the emission but also on emission factors. Concerning the direct measurement, the emission factor needs other parameters to estimate the emission, i.e., the “activity factors”. Specifically, dedicated formulas are required to calculate the total emission, which can also be derived from experience in the field or, more in general, from the experts' know-how (see section 4.15). Due to the complexity and the need to be in contact with the experts in the Consortium, the NHyRA partners agree to discuss more in detail the development of the correlations and of the activity factors that will also be used in WP4 for scenario analysis and to publish the first results in M12 and, finalize them at M18 in accordance with the progress of Task 1.4 and WP4.