Periodic Reporting for period 3 - HIGGS (Hydrogen In Gas GridS: a systematic validation approach at various admixture levels into high-pressure grids)
Période du rapport: 2023-01-01 au 2023-12-31
The results of HIGGS are a clear benefit for society since they will help to enlighten critical issues currently hindering the transport of renewable H2 in gas grids, making possible the decarbonisation of the gas grid and its usages.
The overall objectives are the following:
Identification of critical components in the European high-pressure transmission gas grid susceptible to H2 sensitivitiy.
Investigation of the present RSC of the EU and its member states on limitations regarding H2 concentrations in the gas system.
Experimental testing platform for testing material pipelines and equipment/components at relevant environment (80 bar and under several H2/CH4 blends).
Technical and economic impacts when H2 is blended to the grid by modeling the operation of sections of the NG transmission grid.
Publication of a pathway for stepwise integration of H2 in the EU gas network.
A testing facility at FHA facilities was designed and commisioned (WP3). Actual materials, equipment and components of NG grid can be installed to expose them to different H2 concentrations and pressures.Testing campaigns ranging from 20 to 100 mol% H2 at 80 bar were carried out (WP4) to study the compatibility of different items to H2, regarding H2 embrittlement among another kind of damage due to hydrogen exposure, and potential leakages. H2/CH4 separation was also tackled by a separation prototype based on membrane technology.
Tested representative valves remains tight for the duration of the test, regardless the H2 content in the pipe. Constant displacement C-ring and 4pb steel specimen grades X42, X52, X60 and X70 did not show cracking when exposed to the different H2 gas compositions, at 80 bar pressure and test duration up to 3000 hours. No crack propagation was also noticed for the CT-WOL specimens. The Pd-based membrane prototype developed for H2/CH4 gas separation produced a permeate with a hydrogen purity of 99.5 mol%. Slow Strain Rate tests carried out at Tecnalia´s laboratory for X60 and X70 steels in 100 mol% H2, at 80 bar pressure yielded values of the notched tensile strength ratio indicative of low sensitivity to hydrogen embrittlement.
Regarding the modeling of H2 in the existing NG grid, the NG grid was abstracted as far as possible and considered reasonable and reduced to its essential components (WP5). Based on these fundamentals, a section of the NG grid was modelled in order to be solved numerically. An economic model was to compute transport costs based on the retrofit of the existing grid. The transport costs for hydrogen in different scenarios and contexts were calculated. The results were elaborated into a set of recommendations taking into account different conversion stages regarding the allowed H2 content in converted NG grid.
The potential of H2 injection into the European gas transmission grids in alignment with EU policies was studied (W6) based on the findings from WP2, techno-economic observations with respect to H2 injection into the gas grid from WP5 as well as technical conclusions from WP4. Besides, the interoperability, cross-border transport issues and the gas market management and strategies were reviewed. A pathway towards integrating H2 in the EU gas network was developed. The work performed can be considered as a collection and compilation activity resulting into a kind of compendium of the technical work, impacting regulation, codes, standards as well as implementation possibilities of H2 injection applications within HIGGS.
As part of the EU Hydrogen Week, the HIGGS project and the final results were presented in a closing conference as an official side event. A project brochure. distributed both in printed and digital form at the closing conference, was produced with the aim to condense the project results and make them available in a well edited and illustrated way.
The testing facility built in WP3 has been used for the validation campaign in WP4. The sensitivity to hydrogen of most representative carbon steel pipes has been studied, as well as of components, equipment and joints that can be found in M&R stations, valve nodes, etc. The compatibility with H2 gas of some key elements and components of the NG transmission network grid has been evaluated in the R&D platform built in WP3, allowing H2 exposition for test times up to 3000 hours in each experimental campaign. Constant displacement tests of the API 5L steels under study show no signs of embrittlement. Constant load tests have been complemented with rising load SSR tests. Although the mechanical tests of the API 5L steels indicate a low hydrogen embrittlement susceptibility, additional fracture toughness research should be performed to achieve a proper material certification. The obtained results show that the membrane technology is promising for the H2 recovery and purification of low H2-concentrated gas streams. The membrane prototype should be validated at a larger scale (higher volume to be treated), longer times and with real gas mixtures including impurities and odorants.
The techno-economic model will be able to model the transport costs for hydrogen under a wide range of factors such as configurations of the natural gas grid and a defined demand for natural gas and hydrogen. It can be applied to any size of network at any location. The prerequisite for this is a sufficiently good data situation for the modelling of the network. It should thus serve local authorities as one of many decision-making aids.
The pathway towards integrating hydrogen in the EU gas network has anticipated the behavour of the future grid once hydrogen replaces, completely or partially, natural gas.
The HIGGS final conference at Hydrogen Week in Brussels was able to communicate the message at European level and thus including policy makers, industry, research and the general public that the European gas transport grids are suitable for hydrogen transport and that the grids are largely hydrogen ready. HIGGS project results reached a large number of stakeholders and it has clarified a position on hydrogen readiness at European level.