The Next Energy Pipe Dream: Hydrogen in Natural Gas Pipelines

EDGE, Energy

A critical milestone in the path to a net zero carbon future is known as the ‘20% hydrogen’ goal. As hydrogen is the only clean burning fuel with zero carbon emissions that can be blended with existing fuel for combustion with minimal change to existing combustion infrastructure. 20% refers to the blending of hydrogen with natural gas to reduce overall carbon emissions. The idea is simple: running turbines, or other natural gas processes, with blended hydrogen, can reduce emissions enough to earn us the time to develop new, pure-hydrogen technologies and meet the world’s energy needs and sustainability goals.

The United States, along with International Energy Agency (IEA), is aggressively pursuing the goal of achieving a net zero carbon emission by 2050. Yet, carbon emissions from energy production and industrial processes still account for nearly 36GTon of CO2 as of 2021 (Figure 1) – and emissions levels have shown no signs of slowing down. The 20% H2 blend milestone – and the extra time it earns us – is critical as we advance towards technologies capable of generating ‘green hydrogen’ and processes that run on clean-burning hydrogen alone.

More than 90% of all CO­2 emitted comes from fossil fuel-based energy use (coal, natural gas, and oil). To decarbonize, we cannot wait for a single silver bullet but must leverage innovations that can be deployed now while we further develop net zero fuels and processes. Hydrogen (H2) is considered the primary candidate for the eventual replacement of existing carbon-based fuel but blending it with today’s gas streams yields immediate benefits.

Figure 1: Global CO2 Emissions from 1900 to 2021
Figure 1: Global CO2 Emissions from 1900 to 2021

While producing truly ‘green’ hydrogen remains a major technical challenge, the safe transportation of H2 is one of the critical challenges that can be addressed immediately to help accelerate this global energy transition.

Estimates by EU, IEA, and US Department of Energy indicate that transportation of hydrogen in pipelines is significantly lower in cost compared to other methods, like compression, ammonia storage, or liquid organic hydrogen carriers (LOHC). However, given the lower volumetric energy density of hydrogen vs

natural gas, there is also a need to increase the compression (3X) to reach the same calorific value as natural gas.

A recent IEA report showed the cost of transporting hydrogen in pipelines, including necessary compression, is estimated to be just $0.50/kg vs $3/kg as liquid hydrogen or ammonia via trucking (Figure 2). Pipelines offer significant reach and economic benefits and present an existing infrastructure solution that can be made safe and readily available to transport H2 across the country – and across continents.

Figure 2: Cost of Hydrogen Production
Figure 2: Cost of Hydrogen Transportation

There are over 3 million miles of natural gas pipeline in the US (Figure 3) currently used for moving natural gas from the source to refineries, and on to industrial and residential customers. And the use of existing natural gas pipelines for pure H2 or blended with natural gas has been under consideration for a very long time. Yet, utilizing this infrastructure at the volumes and pressures required comes with challenges – namely hydrogen embrittlement.

Embrittlement, also known as hydrogen-assisted cracking or hydrogen-induced cracking (HIC), is a process in which H2 molecules diffuse into metals and lower the stress needed to cause failures. The highly reactive nature of hydrogen can result in embrittlement, fractures, and fatigue – and with the average age of US pipelines around 50 years (Figure 3), pipes of different metallurgies and mechanical strengths pose a risk.

Even newer pipes, with high-strength steel alloy API-5L-X70 or higher used since the 80s, the presence of hydrogen in the gas stream can be detrimental to the steel microstructure. This safety issue has led some experts to call for entirely new pipelines to be laid down, built from the pipe with metallurgical properties that can resist hydrogen embrittlement. However, this approach would take years to complete and cost trillions to install at a nationwide level.

If existing pipelines could be made safe for H2 blending, refurbishment would provide massive cost and time savings, would require less modification, and possesses right of way (ROW) to implement hydrogen strategy in a short span of time.

Figure 3: Pipeline Map of the US

HydroPel: An Advanced Nanocomposite Surface Protection

Transforming existing natural gas pipelines to accommodate H2 blending requires a new technology that can mitigate H2 diffusion into steel microstructure. The current state-of-the-art approaches, utilizing materials such as PTFE, polyethylene, and rubber-based materials, require a complex application process that results in significant constriction in diameter and therefore flow.

Current liners or coatings add thickness (>20mil) to pipe walls and are difficult to install and are prone to leaks due to challenges in varying-sized connections, weld joints, and so on. To address this unique challenge, Oceanit developed an advanced nanocomposite surface protection: HydroPel. The nanocomposite is a sub-4mil thickness surface treatment, that prevents H2 diffusion and can be applied in situ or at the pipe production stage. When exposed to embrittling H2 environments HydroPel-treated steel showed a negligible change to tensile strength and specified minimum yield strength (SMYS), compared to unprotected bare steel which failed due to hydrogen embrittlement (Figure 4).

As of 2022, experts estimate a cost $4.65 million/mile (36” diameter) to lay new pipelines. HydroPel can be applied to existing pipelines at just $0.239 million/mile –1/20th of the cost.

Based on an in-depth techno-economic assessment (TEA), it is estimated that repurposing the existing 36” diameter pipeline with HydroPel would be just 6% of the cost of installing a new hydrogen pipeline. Repurposing 10,000 miles of existing pipeline with HydroPel technology would provide savings of close to ¼ trillion dollars over a 40-year time span.

Figure 4: Fracture Resistance of Steel
Figure 4: CAPEX Savings on New vs. HydroPel Repurposed Natural Gas Pipeline

Utilization of H2 as a carbon free energy source requires scalable technologies that can be readily implemented in our existing energy infrastructure. HydroPel can solve the H2 transportation challenge, but is just the first step in global decarbonization.

Pipelines are the arteries of any country, carrying essential ‘energy’, in the form of oil and natural gas. Slowly replacing natural gas with hydrogen in these arteries will accelerate our transition in energy generation and utilization and directly address net zero carbon emission goals. Ensuring the performance and safety of pipelines is critical before implementing such changes in gas composition.

To make the pipe dream of utilizing existing natural gas pipelines for H2 transport a reality, a technological solution that is disruptive, scalable, and efficient is required. HydroPel builds upon years of experience in protecting and improving pipeline efficiency and can deliver on the necessary needs for safe H2 transport, promoting immediate decarbonization in the energy sector.

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