Executive viewpoint
Hydrogen is set to play a major role in the energy transition, as the world seeks sustainable solutions to reduce greenhouse gas emissions and achieve climate goals. As a versatile energy carrier, hydrogen can be produced from various renewable sources, making it a crucial element in decarbonizing sectors that are difficult to electrify, such as heavy industry, aviation, and long-distance transportation.
Investment levels. Its potential for large-scale storage and transportation further enhances its appeal. Globally, governments and industries are investing heavily in hydrogen technologies, recognizing its ability to provide a stable and clean energy supply. Innovations in production methods, such as green hydrogen derived from water electrolysis using renewable energy, are driving down costs and increasing feasibility. As infrastructure and regulatory frameworks evolve, hydrogen’s integration into the global energy mix is only set to accelerate.
The estimated global expenditure on hydrogen production for energy purposes—from now until 2050—is expected to reach $6.8 trillion, with an additional $180 billion allocated for hydrogen pipelines and $530 billion for the construction and operation of ammonia terminals. While uptake of hydrogen will differ significantly by region, it’s expected that Europe, Asia-Pacific, North America and greater China will consume two-thirds of global hydrogen demand for energy purposes by 2050.1 However, one of the major challenges to adopting hydrogen on a global scale is the logistics of the gas supply chain.
Pipeline utilization. As investment in the sector ramps up, the use of pipelines for hydrogen transportation is generally considered the most cost-effective method and, therefore, an increasing area of focus for the industry. The United States, alone, already has more than 3 million mi of natural gas pipelines and over 1,600 dedicated pipelines, so adapting these networks to leverage existing infrastructure has several advantages.2
Blending hydrogen with natural gas allows the industry to repurpose pipelines for hydrogen transportation while also supporting the gradual integration of it into energy systems. However, the properties of hydrogen present several challenges with materials compatibility in pipelines and compressors, which were not originally intended for hydrogen transportation. In one study, a 60% loss in ductility of current pipeline materials, when exposed to hydrogen, was reported.3 Embrittlement of steel, fatigue crack growth, and loss of ductility present constraints that must be addressed.
Corrosion threat. Pipeline coatings are a widely used method to mitigate corrosion, acting as a physical barrier between the pipeline material and hydrogen to stop the gas coming into direct contact with the metal surface. While effective, particularly when combined with other protective measures, such as cathodic protection, coatings have some limitations. The coating material must be compatible with hydrogen and any other chemicals within the pipeline, or there is risk of degradation, therefore reducing their effectiveness. Hydrogen molecules can also diffuse through certain coatings, leading to embrittlement, which can be costly to repair. Additionally, holidays in the coatings can lead to exposure of unsuitable metallurgy to hydrogen, leading to increased risk of material failure.
So, at such a critical time in the energy transition, how can the industry combat these issues to successfully advance hydrogen adoption?
Despite the growing urgency for solutions to support the hydrogen economy, to date, there has been minimal research exploring the potential to apply corrosion inhibitors as an effective mitigation method. Widely used within the oil and gas industry, chemical corrosion inhibitors are used in environments that contain water, carbon dioxide, hydrogen sulfide, and various organic acids, which can lead to significant corrosion and damage to pipelines, equipment, and storage facilities.
Testing corrosion inhibitors. However, to help plug this gap, ChampionX is one of the companies that has conducted testing procedures. In particular, resistance of the hydrogen absorption on materials, such as API X65 (UNS K03014) steel, in the presence of different corrosion inhibitors was tested. API X65 specimens were immersed in the inhibitors ahead of cathodic charging testing. It was observed that the specimens immersed in the inhibitors reached a threshold that impeded the hydrogen from being absorbed into the material, instead causing the atoms to recombine to form hydrogen molecules and resulting in them leaving the surface. The presence of the film inhibitor reduced the available area for electrons to recombine with H+ and decreased polarization resistance.
With a growing demand from the market, there is scope to further explore and research the possibility of using corrosion inhibitors to enable the use of existing pipeline infrastructure for hydrogen transportation. While the best solution for constructing new infrastructure would be to identify the appropriate metallurgy, in the same way that materials were selected specifically for natural gas transportation in the past, there are significant benefits to reusing existing infrastructure to advance the hydrogen transition.
The use of chemicals to protect existing assets provides a cost-effective solution, compared to the extensive and expensive process of replacing pipelines with new, hydrogen-resistant materials. Many oil and gas pipelines are also already equipped with systems to inject and monitor chemical corrosion inhibitors, making the transition relatively straightforward from an operational standpoint. Corrosion inhibitors can also be controlled and adjusted, based on real-time monitoring of pipeline conditions, enabling more adaptive management strategies to ensure optimal protection.
If the uptake and use of hydrogen advances as quickly as predicted, corrosion inhibitors can be implemented and monitored easily for performance through a robust inspection program. Part of this transition will involve engaging with pipeline operators to confirm and reassure that the use of corrosion inhibitors is a valid, safe and cost-effective solution to the transportation problem. However, the corrosion inhibitors currently used in natural gas production and transportation will need to be carefully considered, as some may be incompatible with hydrogen, leading to the formation of gunk or deposits.
As the energy transition continues at pace, and hydrogen becomes an increasingly viable player in a net zero future, chemical corrosion inhibitors present a clear opportunity for supporting its large-scale adoption. However, investing in research and development is crucial in realizing their potential, and supporting the safe and sustainable transport of hydrogen.
REFERENCES
1. https://www.dnv.com/focus-areas/hydrogen/forecast-to-2050/
2. S. Department of Energy, “HyBlend: Opportunities for hydrogen blending in natural gas pipelines,” Hydrogen and Fuel Cell Technology office, December 2022.
3. Hardie, D., A. Charles, and A. H. Lopex, ‘Hydrogen embrittlement of high strength pipeline steels’, Corrosion Science, Vol. 48, pp. 4378-4385, 2006.
