The European Commission's Climate Target Plan aims to reduce greenhouse gas emissions to net zero by 2050. Hydrogen is considered an important element in achieving these targets, and a hydrogen-based economy requires safe and cost-effective transportation and storage methods. One option gaining consideration is pressurized gas transportation and storage, which takes advantage of existing pipeline infrastructure. To this end, the European Hydrogen Backbone initiative has been launched, with 31 energy infrastructure operators working to develop a dedicated hydrogen network, primarily through the repurposing of existing pipelines. One of the main challenges in this initiative is ensuring the material suitability of pipelines for hydrogen service, given the unique properties of hydrogen that can affect the material properties of steel pipelines.
This paper presents RINA experience gained during an independent verification of the material suitability to hydrogen service of the pipeline network operated by the main Italian TSO, SNAM.
To correctly perform such verification a preliminarily setting exercise with the following two key objectives, has been performed: (1) defining clear and consolidated technical acceptance criteria based on the review of the available codes, standards, and literature supported by dedicated considerations made by material and pipeline engineering experts and (2) developing a multi-level methodology whose approach is fine-tuned for each the stages of the repurposing project.
During phase 2 of the project the proposed methodology was adopted; a review of SNAM Company Specifications and gap analysis was performed with subsequent assessment of material suitability of approx. 1148 km of existing pipelines operated by SNAM to convey up to 100% of hydrogen.
The approach in this document refers to the assessment of the suitability of the pipeline from a materials perspective. Prior to injecting hydrogen into a pipeline, other aspects (e.g., integrity and risk assessment, flow assurance, HSE assessment, etc.) shall be performed in the appropriate project phase; the definition of relevant methodologies is not covered in this document and shall be developed separately.
