Hydrogen (H₂) is becoming a central talking point as the world moves towards a net-zero energy economy. It has many potential applications, supporting and accelerating the transition from fossil resources to a low-carbon future. For example, it can replace conventional hydrocarbon fuels in the transportation/mobility sector. As an industry feedstock, it can help decarbonize hard-to-abate sectors such as steel and chemicals. It can also provide heat to industry and buildings. Even just looking at the production of ammonia, which currently accounts for more than 1% of global carbon dioxide emissions, H₂ has the potential to significantly reduce this footprint. In addition, hydrogen can be used as a green vector to store excess energy produced from renewables such as wind and solar and then release that renewable power on demand. These are just a few examples of how hydrogen can help meet the goals outlined in the Paris Climate Agreement.

There is a catch, however. Hydrogen is rarely produced at the point of use. And green hydrogen is contingent on the availability of renewable resources, which are subject to wide seasonal and regional fluctuations – often making it even more difficult to synchronize supply and demand. So how can the point of production be connected to the point of use?  Bulk deliveries by means of liquid tanker trucks or gaseous tube trailers are commonly used today. Some H₂ pipelines have also been laid in high-volume industrial clusters. Linde covers all of these conventional supply modes. But to power the energy transition, hydrogen distribution and delivery capabilities would need to scale up and out. Ultimately, the vision for a hydrogen future hinges on a dedicated hydrogen gas pipeline network. Building a pipeline infrastructure from scratch, however, would be prohibitively expensive and extremely time-consuming. 

And this is where the chicken and egg dilemma kicks in. The development and delivery of extraction technologies only make sense if there is demand for these solutions. In other words, if hydrogen is already being blended with natural gas. But what transmission system operator is going to blend hydrogen with natural gas if the appropriate extraction technologies are not readily available?  As Linde is now demonstrating at its real-scale pilot plant in Dormagen, Germany, that dilemma has now been resolved. Combining Linde’s HISELECT^® powered by Evonik ultra-selective membranes with Linde’s high-performance pressure swing adsorption technology, this facility is already separating hydrogen from natural gas on a real-world scale, varying the concentration of hydrogen from 5% to 50%. This pioneering facility provides clear proof-of-concept, showing that the separation and purification technologies required downstream to extract hydrogen from the pipeline or natural gas blend are not just available – they also work in real-life conditions. “We see the Dormagen plant as a key milestone in our transformational technology roadmap. By supporting the transition from a natural gas to a hydrogen-blended pipeline, we are providing the bridging technologies for our hydrogen network vision,” says Tobias Keller, Head of Product Line Adsorption and Membrane Plants at Linde.   

HISELECT membranes work by filtering gas molecules according to their size. They consist of asymmetric hollow fibers made of polyimide with a nanometer-scale selective layer on the fiber outer shell. The fibers are coiled up in a cross-counter winding pattern, forming a structured packing for optimal flow distribution. The membrane system delivers robust performance even under high pressures and harsh pressure fluctuations. This makes HISELECT modules more resistant to pressure shocks and reversal of transmembrane pressure than conventional flat-sheet modules. As hydrogen is a very small and fast molecule, it permeates very quickly through the membrane to the pressure-less side. Natural gas behaves differently. It is quite a large molecule, so it stays outside the membrane fiber, and is thus retained on the high-pressure side. 

Now that Linde has established the viability of hydrogen extraction technologies from pipeline blends, attention is inevitably turning to deployment opportunities. The vision of a hydrogen pipeline network may be closer than one would think. The first projects to advance hydrogen pipeline networks are already underway. Take the European Hydrogen Backbone (EHB) for example. Eleven European transmission system operators (TSOs) joined forces to build and expand a hydrogen backbone in Europe. The updated EHB report published in 2021¹ outlines a much more ambitious hydrogen pipeline transport network plan based largely on repurposed existing gas infrastructure with concrete infrastructure maps for timelines from 2030 to 2040.
“Our Dormagen plant has created strong market traction – catching the attention of many different customers and operators. We are seeing growing interest in the possibilities of this novel technology mix as it connects the highly diverse and geographically distributed production base for hydrogen with the point of use,” says   Oliver Purrucker, Head of Business Development and Sales at Linde.