Overview of carbon steel pipelines in use for natural gas transmission in Europe and their potential reuse for hydrogen transport

Background In order to decarbonize the European industry at an affordable cost, it is necessary to reuse part of the existing natural gas transmission pipeline infrastructure for hydrogen transport. Before doing so, the compatibility of the different types of carbon steels used for constructing these pipelines needs to be demonstrated for hydrogen service. This is the purpose of the European project PilgrHYm ( Pre-normative research on Integrity assessment protocoLs of Gas pipes Repurposed to Hydrogen and Mitigation guidelines) gathering five industrial and seven research partners. Methods The first task of this project was to gain a clear picture of the different types of steel pipelines currently in operation all over Europe for natural gas transport. To do so, a questionnaire was prepared and sent to all natural gas Transmission System Operators (TSOs) in Europe to gather updated information about their pipelines. Results A total of 23 responses to the questionnaire were received from onshore TSOs, covering a global length of 182469 km of carbon steel pipelines. A general analysis of these responses is presented in this article, with a focus on different parameters: steel grades, pipeline diameters, wall thicknesses, construction years, fabrication types, typical operating pressures with natural gas, and envisioned reuses for hydrogen transport. Conclusions Results of this analysis were used to help select twelve representative carbon steel samples that are being investigated experimentally in the PilgrHYm project.