Breaking Ground: Electrochemical Techniques for Rapid and User-Friendly Evaluation of Material Compatibility in Hydrogen Infrastructure
Authors: Gennaro M. E. , Iorio V. S. , Todesco F. , Pontarollo A. , Torri L. , Nutricato G. , Bianchi M. 
Published: November 2024

Energy companies worldwide are dedicated to achieving decarbonization by 2050. These companies are evolving their products and processes toward sustainability as part of this collective effort. Underground Hydrogen Storage stands out as a crucial decarbonization role within the integrated strategies of energy companies. This paper aims to evaluate the compatibility of metallic materials for transportation and storage using electrochemical techniques for charging hydrogen as an alternative to high-pressure environment exposure tests.

In the development of Underground Hydrogen Storage, a thorough examination of potential processes stemming from associated risks during injection and transportation is imperative. Hydrogen interactions pose complexity due to their unfamiliar nature, potentially resulting in unpredictable behavior in subsurface environments. Thus, analyzing the compatibility of casing and tubing materials with hydrogen is crucial, particularly concerning phenomena like hydrogen embrittlement and hydrogen-induced cracking. Additionally, in hydrogen transport, the necessity for high-strength steels due to high pressures and large sizes presents challenges, as these materials are more susceptible to hydrogen damage.

The ASME B31.12 code currently stands as the sole guideline for hydrogen service pipelines, stipulating stringent limits on maximum operating and design pressures based on steel grade and material properties for both new and repurposed pipelines. However, compliance entails extensive testing under high-pressure hydrogen gas conditions, a time-consuming (minimum of 1000 hours) process that only a few laboratories can undertake. This paper proposes an alternative approach employing electrochemical techniques. By simulating a hydrogen atmosphere through electrochemical cell processes, specimens undergo cathodic charging in an aqueous solution, mimicking hydrogen's chemical activity under pressurized conditions. Subsequent fracture mechanics tests ascertain the fracture toughness of hydrogen-affected materials, allowing for comparison with their original state.

The electrochemical charging allows a pre-characterization of materials so that the extensive and demanding tests required for their full qualification are applied only to the most promising ones with low probabilities of failure. Tests were performed on six different steels API 5L X60 Q&T and TMCP, and API 5CT L80-1, J55, T95, and P110. Results showed that the proposed method can bring to light the different behaviors of different materials. In the worst scenario, it allows to perform the preliminary characterization in a couple of weeks.

This paper offers a novel approach to evaluating metallic materials' compatibility for hydrogen transportation and storage, presenting electrochemical techniques as an alternative to high-pressure exposure tests. This innovative approach contributes valuable insights to the existing literature, particularly in addressing the challenges of hydrogen susceptibility in high-pressure environments. These results constitute a pivotal initial step for de-risking the study of underground hydrogen storage.