Under the leadership of Energienetze Steiermark GmbH, a consortium consisting of the Austrian Association for Gas and Water (ÖVGW), research institutions and the industrial services provider Bilfinger intends to use the knowledge gained in "HyGrid2" to answer open questions by 2025, which should make future rededication possible. These include the inspection and cleaning of the pipelines, the quality of the transported hydrogen, the application-oriented purification of H2 and the H2 compatibility of the individual components and materials used.
In the course of the project, the first Austrian natural gas steel pipeline section in the grid area of Energienetze Steiermark will be converted for hydrogen transport and developed into a demonstration plant together with Bilfinger's Austrian subsidiary Bilfinger Industrial Services GmbH. The former natural gas pipeline is operated with pure hydrogen under real conditions in order to gain knowledge for practical use.
The special challenge of the conversion lies, on the one hand, in the requirements for the purity of the pipelines. In the case of existing pipelines that are converted to transport hydrogen, the previous use is relevant and has an influence on the quality. In the "HyGrid2" pipeline conversion project, there is also the fact that the network section was operated with odorised gas, i.e. gas mixed with odour-intensive substances: In Austria, but also in some other countries such as France and Norway, the almost odourless natural gas is odorised with sulphur-based compounds when it enters the gas distribution network in order to make an unintentional gas leakage detectable at an early stage. Within the framework of HyGrid2, studies on the influence of the odorised pipeline on the transportable hydrogen gas quality are therefore essential for the operation of converted pipelines.
Within the framework of its research programme "Green Gas 4 Grids", the ÖVGW had already investigated in the pilot study "HyGrid" which impurities can occur in the hydrogen when it flows through pipelines that have been "repurposed" from natural gas pipelines to pure hydrogen pipelines. These can be odorous substances or other natural gas components.
Another challenge is the material suitability of the existing infrastructure for hydrogen transport. Here, in contrast to natural gas, so-called "hydrogen embrittlement" can occur, i.e. diffusion and dissolution of hydrogen in the microstructure of metal pipes. Over time, this can lead to damage to the pipes and thus to the formation of leaks. Bilfinger will use the pipeline demonstrator to test the existing natural gas infrastructure for its suitability for hydrogen transport using various non-destructive testing methods and modify it if necessary.
"HyGrid2" also aims to use the results of the pipeline demonstrator to create a manual for the successful rededication of natural gas pipelines. This should cover the technical, economic and legal framework conditions and include the current state of science as well as the regulatory requirements and organisational processes. The handbook will serve as a guideline to accelerate the rededication of natural gas pipelines for H2 transport in the future, so that green hydrogen can realise its potential for a 100% sustainable and independent energy supply.
HyGrid² is a research project funded by the Climate and Energy Fund and carried out as part of the "Vorzeigeregion Energie" WIVA P&G programme.
Project consortium: Bilfinger Industrial Services GmbH, ÖVGW, DBI Gas- und Umwelttechnik GmbH, Energienetze Steiermark GmbH, Materials Center Leoben Forschung GmbH, HyCentA Research GmbH, Montanuniversität Leoben - Chair of General and Analytical Chemistry, WIVA P&G