Could Hydrogen Transport Mean Sustainability for the Pipeline Industry
The United States has a significant natural gas transportation and storage network. While companies are exploring transporting hydrogen using existing assets, careful consideration needs to be given to hydrogen's unique properties, and how they may impact pipeline assets.
Sustainability and climate change awareness are increasingly becoming the key objectives of many organizations in response to climate change initiatives. If the world is to come anywhere near meeting its climate change goals, the oil and gas industry will have to play a role; statistics suggest that this industry alone accounts for 9% of all human made greenhouse gas emissions. One direction a number of companies in the natural gas industry are exploring is progressively using and/or repurposing existing pipeline infrastructure for conveying hydrogen, a low-carbon molecule.
As a result, investing in hydrogen technology is becoming attractive and important, both as a means to help governments reach their climate change goals, and as a path to economic recovery through clean technology leadership. Many people believe leveraging the natural gas grid to transport hydrogen is a realistic path toward achieving sound energy policy, environmental stewardship, and economic prosperity.
Climate Change and Use of Hydrogen
Carbon-capture technology has been around for decades and is already used in some industries. It also plays a vital role in reducing the carbon emissions of pipelines. In fact, it is estimated that it will reduce industrial emissions by as much as 46% in 2050. The major technologies proposed for carbon capture include membranes, oxyfuel combustion, absorption, multiphase absorption, adsorption, chemical looping combustion, calcium looping and cryogenics. Absorption, or carbon scrubbing with amines is the dominant capture technology currently used. However, carbon capture needs to be more cost-competitive by the end of the decade to achieve the rate of deployment needed to help nations reach net zero, according to many analysts and industry experts.
Even with carbon capture, however, climate change and the move to build legislation around it has made the future of many pipelines in the U.S. and Canada uncertain as countries aim to move away from fossil-burning fuels. Unlike natural gas, however, hydrogen can be burned without emitting carbon dioxide into the air. It can also run through a fuel cell to generate electricity with water as the only waste. Hydrogen is considered clean only if it is produced using low- or no-carbon emitting energy sources like biomass, nuclear, renewables or fossil fuels paired with carbon capture technology, but it can be produced using electrolyzers powered by solar plants or wind farms, and it can become a means to store large amounts of renewable energy as well.
From an environmental perspective, adding hydrogen to natural gas could significantly reduce greenhouse gas emissions. With hydrogen blending, the carbon concentration of the natural gas will be reduced.
Perhaps the greatest advantage, however, might be that it is believed that hydrogen can use the same basic infrastructure that now carries natural gas.
The Pitfalls of Leveraging Natural Gas Infrastructure for Hydrogen Transport
Hydrogen can be transported in the form of gas in high-pressure containers, as a liquid in thermo-insulated containers, in processed form as methanol or ammonia, or in a chemical carrier medium. However, the most economically viable method is via a pipeline. Hydrogen, with its smaller density, corresponds to a lighter mass than that of methane given the same volume. This means that the same pipeline infrastructure can transport more hydrogen during a given period at the same pressure, while the energy transportation capacity is only slightly smaller.
However, transporting hydrogen through a pipeline designed for natural gas may lead to an increased risk of leakage without proper seals, as hydrogen is a much smaller molecule than natural gas. Hydrogen is also much lighter, which means compressors designed to move natural gas tend not to work well.
Another limiting factor is the material durability of existing pipelines. Some types of steel pipes can degrade when they are exposed to hydrogen in high concentrations and at high pressures, while polymer pipes are able to better handle hydrogen.
Due to the different physical and chemical properties of hydrogen compared to natural gas, the existing natural gas system requires careful evaluation and verification to ensure compatibility and safety. The effect is highly dependent on the specific material compositions and must be assessed on a case-by-case basis.
Fortunately, pilot projects around the world are testing hydrogen transport via existing pipeline infrastructure, including blending hydrogen with other fuels and testing different pipeline materials.
The Role of Isolation Gaskets in Hydrogen Fuel Transport
Compared to natural gas, hydrogen is much more prone to leakage, especially from pipeline segments not initially designed for its transport, due to the small size of the hydrogen molecule. As such, leakage prevention becomes an essential consideration that needs to be addressed through the careful selection and installation of tight seals, as well as proper testing. An example of a pipeline seal that is suitable for modifying existing conveyance to transport hydrogen is GPT EVOLUTION Isolation Gaskets. EVOLUTION is a fully encapsulated isolating gasket with 3mm thickness. Its minimal thickness helps make installation easier, and its total encapsulation allows the gasket to be hydro-tested to ensure a pipeline is fully sealed.
EVOLUTION has dual seals on the inside diameter: concave GYLON Inside Diameter (ID) seal and PIKOTEK VCFS seal. The latter is a secondary seal that is seated in an insulating laminate and permanently bonds to the pipe metal core/inside diameter. The seal diameter is slightly larger than the pipe inside diameter that makes it matches the pipe bore under compression. The seals stop any media from permeating to/from the pipe and reduces the EVOLUTION’s leak rate to only 1 cc of helium every 10,000 years on average. As a result, EVOLUTION is a viable sealing solution for conveying many substances, including hydrogen gas.
EVOLUTION has also been tested exhaustively in sour media tests, which contains measurable amounts of hydrogen sulfide, that have resulted in no permeability and no degradation, which will not only meet the industry needs, but also provides a high-performance standard. The product is fire safe, and is already being applied successfully in hydrogen applications.
The Bottom Line on Transporting Natural Gas
The United States has a significant natural gas transportation and storage network. While companies are exploring transporting hydrogen using existing assets, careful consideration needs to be given to hydrogen's unique properties, and how they may impact pipeline assets. More testing needs to be done, but the smaller molecule size of hydrogen suggests that proper sealing of pipeline components will be a key factor in maintaining pipeline integrity.