Repurposing Natural Gas Pipelines for Hydrogen – What to expect?

Three million miles of natural gas pipelines criss-cross the U.S., and in the fight against climate change, they could become obsolete. What is in store for European pipeline operators as they try to evolve to the need of the hour? 69% of the European natural gas pipeline network of over 2.2 million kilometers is expected to be repurposed for Hydrogen Transmission. How will pipelines cope when you blend hydrogen into the natural gas network. Read on to explore with us all the major pain points and possible solutions


Hydrogen will be adding about 13-14% by 2050 in Europe’s energy mix. Currently, operators and utilities are relying on the well-spread

European gas infrastructure that crisscrosses and covers 2.2 million kilometers, with 1,200 TWh of underground storage capacity.

Though many companies are already blending hydrogen concentrations as high as 20%  in natural gas networks, there hasn’t been a conclusive study on the long-term effects of hydrogen on materials and equipment typically used for natural gas transmission. The Energy industry is thus finding itself in uncertain territory.

Blending Hydrogen with Natural Gas

It is not really whether operators will pursue blending. It is more to do with how and what percentage is feasible for them. Gas pipeline owners also won’t be able to switch from one gas to another without cutting ties with their existing customers. And that is going to pinch. Thus many operators are transitioning by blending hydrogen with the existing fuel.

This is where the problem would start. Compressors that were designed for natural gas won’t work that well with hydrogen owing to it being lightweight.

If the amount of hydrogen injected into the natural gas grid keeps increasing, then there is a potential for hydrogen embrittlement of steel. This would weaken the metal or polyethylene pipes, causing safety hazards and combustion instability.

Compressor stations, elastomeric materials used in fittings and gaskets and gas meters could become obsolete. And without these elements, there is a palpable concern for safety and the negative impact on the environment.

The ability of Hydrogen to attack metal structures depending on variables such as certain pressures and concentrations further adds to the woes of the material scientists.

You can further read more on the challenges ahead for Europe’s Hydrogen Roadmap, here.

The three major pain points that stick out are:-

  • Pipeline compatibility with hydrogen
  • Impact on Environment and the Overall Costs 
  • Hydrogen’s effect on appliances and other equipment

The European HydroGen Backbone (EHB) estimates that it can convert 69% of the existing natural gas pipelines in order to stick with Europe’s Hydrogen Roadmap.

Go with the Flow: Current status for Natural Gas Pipelines

A complete switch to a 100% hydrogen pipeline will require a whole lot more installations – like new turbines, motors and compressors. Probably the reason why 85% of hydrogen doesn’t move at all in Europe, observes Rauf Fattakh, Managing Director & Co-founder Prospero Events Group.

The re-purposing costs of natural gas pipelines for 100% hydrogen transportation are projected between €0.2 million and €0.6 million per kilometer. While subsidies can definitely help in making the transition more economically feasible, there is the need for stable political guidelines to foster companies and promote trans-national interconnecting gas pipelines in the long term.

The financial considerations will then come down to capacity. Some gas TSOs are inkling towards operating hydrogen pipelines at less than their maximum capacity as it makes more sense for the per megawatt-hour transported. National Grid for one is working on the “FutureGrid”- a project to demonstrate how the existing gas network can be utilized effectively for hydrogen transportation at full transmission pressures. These tests will help us understand how our gas assets could perform when exposed to the different hydrogen levels. At the 9th Pipe Maintenance and Integrity Management 2021, Tom Neal, Innovation Delivery Manager and Lloyd Mitchel, Pipelines Engineer at National Grid will share insights on Re-purposing a High-Pressure Natural Gas Pipeline System for Hydrogen Transmission, and lead discussions on assessing risks and potential mitigations, and materials concerns for change in the fluid.

The Silver Lining

Jack Brouwer, director of the advanced power and energy program at the University of California, believes that existing pipelines can adapt to transport hydrogen. But that this is inherently a slow process that could take years.

“We could replace problem pipes and compressors. Or we could protect pipes with coatings applied from the inside by pigs that are currently used for pipeline inspection and maintenance,”

he opined. Even spray painting the insides of the pipes, he believes, could be a start.

Polymer pipes are also touted as a solution, as they can better handle hydrogen. In Europe though as an IRENA expert affirmed it won’t be necessary when transporting lower blends of hydrogen, as the existing infrastructure is usable.

Laboratories, industry experts and academia are actively seeking more answers, and a recent venture by the National Renewable Energy Laboratory’s (NREL) R&D called HyBlendTM is promising. With over 20 participants from industry and academia and funding of over $10 million of funding from EERE (Energy Efficiency and Renewable Energy), they will be looking closely at three major pain points mentioned above.

What other alternative pathways do operators need to consider before committing to using hydrogen-gas blends at large scale? What is the actual impact on the gas and pipeline companies’ exchequer? Does the repurposing of natural gas pipelines have any environmental implication?

Join us online for insights on repurposing natural gas lines for hydrogen, and discussions with experts on pipeline maintenance and integrity challenges at 9th Pipe Maintenance and Integrity Management on October 14th and 15th.

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