Hydrogen (H2) is growing in importance across an increasingly broad spectrum of applications and use cases. To meet this trend, Linde has doubled the H2 liquefaction capacity at its Leuna site in Germany and has commissioned a second plant in early 2021. 

In addition, Linde continues to expand its production capacity for green hydrogen by constructing the world's largest PEM (proton exchange membrane) electrolyzer at its Leuna site, planned to start production in 2022. The electrolyzer is being built by ITM Linde Electrolysis, a joint venture between Linde and ITM Power. With a capacity of 24 megawatts, this project is a crucial step for the growth of clean energy in Germany. 

"Hardly any other site offers such a wide range of hydrogen-related plants and products," explains Thierry Rousson, Head of Product Management Hydrogen & Syngas at Linde. "Accordingly, the portfolio of our process technologies used at our Leuna plant is also extensive. The site showcases our pivotal role in contributing to the development of the hydrogen infrastructure as a technology innovator and the largest operator along the entire H2 value chain,” adds Rousson.

Linde’s H2 success story in Leuna began in the early 1990s with the establishment of its first steam reforming plant. This event created the foundation for Linde's hydrogen business at the site. 

"From that point on, our hydrogen business has gone from strength to strength," explains Joachim Pretz, Remote Operations Center (ROC) Manager at Leuna. "We added a pipeline network and liquefaction facilities, followed by a second steam reformer. Today, the site produces approximately 80,000 standard cubic meters of hydrogen per hour," says Pretz. 

When a reformer is operating at full capacity, it processes 15,000 cubic meters of natural gas per hour in addition to steam. Because natural gas is a fossil resource, the hydrogen produced is referred to as gray H2. At present, gray hydrogen still accounts for more than 90 percent of the H2 mix at Leuna, but the focus is shifting to blue and green hydrogen. The production of clean H2 is becoming more and more important. The production of blue hydrogen also uses natural gas as a feedstock, but the carbon dioxide (CO2) generated by the steam reforming process is not released. Instead, it is captured and stored (Carbon Capture and Storage). 

"We are currently engaged in conversations with a leading oil and gas company to explore the possibility of transporting the captured CO2 by pipeline to the North Sea and storing it there," continues Pretz. Looking beyond blue H2, momentum for green hydrogen is also picking up at Leuna.

Linde is driving the technology and infrastructure innovations needed to accelerate the transition to lower-carbon forms of hydrogen. As Andreas Dietrich, Linde’s Head of On-Site Account Management North & East Germany at Leuna explains, "Demand for green hydrogen has risen significantly in recent years. We have been producing it from green electricity and biomethane since 2012, as our reformers can also run on biomethane." Currently, the green hydrogen share at Leuna is five percent. Linde can tailor the output at Leuna to meet customer needs, calculating in advance how much green electricity and biomethane would be required to generate a green H2 stream for any given customer." Although the same plant can be used to produce gray and green hydrogen, the raw material – biomethane – is a much more limited resource than natural gas. That's why we can't ramp up clean H2 production on demand," explains Dietrich. "At the moment, for example, we must preorder our biomethane in the fall for the following year."

To enable widespread adoption of clean hydrogen, Linde is investing heavily into alternative production methods at Leuna. In January this year, the company announced that it will build and operate the world's largest electrolysis plant. Scheduled to go on stream in the second half of 2022, it will supply industrial customers with green H2. Linde will then produce 4,500 standard cubic meters of hydrogen per hour through electrolysis. Powered by renewable energy, the PEM electrolyzer will produce up to 3,200 metric tons of green hydrogen per year from mid-2022 onwards. This would be sufficient to power around 600 fuel cell buses, enabling them to travel 40 million kilometers while saving up to 40,000 tons of carbon dioxide emissions per year.

"Purification processes vary depending on whether the hydrogen was generated by steam reforming or electrolysis," explains Rousson. "While steam reformers have a pressure swing adsorption (PSA) system downstream for this purpose, the electrolysis process flow requires a de-oxo and drying step." Gaseous hydrogen produced at Leuna with a high purity is then either pipelined or transported in a H2 trailer to customers. Leuna is already equipped with an excellent network of gas pipelines and storage facilities, and Linde plans to expand this infrastructure in the coming years to accommodate larger H2 offtakes. 

"But we also support smaller businesses and laboratories with hydrogen in gas cylinders," Pretz says. "We currently supply hydrogen to about 22 customers in the region and are expanding our green H2 capabilities," Pretz continues. "In addition, we are looking into solutions to temporarily store hydrogen in existing high-volume caverns." Those developments should position hydrogen as an attractive energy vector, capable of balancing fluctuations in the availability of renewable energy sources like solar or wind energy.

According to Linde experts, demand for liquid hydrogen (LH2) in particular is set to increase in the coming years. "Currently, there are only three liquefaction plants in Europe that can cool hydrogen down to the minus 253 degrees Celsius required for liquefaction," explains Rousson. "To support growing demand, we are building another H2 liquefaction plant in Leuna, scheduled to go on stream in 2021." 

The site will then feature two liquefiers, both equipped with Linde’s proprietary hydrogen liquefaction technology offering market-leading levels of efficiency. The new plant will effectively double Leuna's liquefaction capacity from the current five tons to ten tons per day. Both liquid and gaseous hydrogen can be transported to customers in custom-designed trailers. "Due to its higher energy density, LH2 has advantages as it requires less space. You only need one truck to transport the same volume of hydrogen that would require ten trucks in gaseous form," explains Pretz. “So you save nine trips – and thus fuel." 

This advantage is especially significant for long, more frequent routes. As today's hydrogen infrastructure continues to expand, the additional effort involved in liquefaction is set to pay growing dividends. And the steady buildout of Linde's pioneering network of refueling stations, which use liquid hydrogen to support pressurized refueling, is likely to further increase demand for LH2. With a holding time of about three weeks, the special cryogenic tanks also increase the reach of LH2.

At present, the supply routes from Leuna extend across almost all of Europe, reaching as far as Spain and Greece. However, the regional electronics industry, as one example, also relies on high-purity hydrogen from Leuna for semiconductor manufacturing. And local chemicals customers need H2 for various processes such as fuel desulfurization and hydrotreatment. In the steel industry, hydrogen is an increasingly popular replacement for natural gas. The regional customer base includes automotive manufacturers, where use cases include powering a fuel-cell forklift fleet of 110 vehicles. In addition, Linde supplies Leipzig airport’s H2 fueling station, operated under the H2 Mobility umbrella, with hydrogen from its Leuna plant and with proprietary fueling technologies for H2. Building on many years of expertise in hydrogen infrastructure solutions, the company's expertise extends to innovative cryogenic compression and pumping technologies for hydrogen dispensers.

The possibilities of hydrogen extend to other exciting new use cases. For instance, hydrogen is being considered for a pioneer energy project, says Dietrich. "The idea is to feed one of the turbines of a gas-fired power plant in Leipzig with green H2 for a zero-carbon source of energy." At the same time, Linde is working with Germany’s Fraunhofer Society (Fraunhofer Gesellschaft) to set up a large electrolysis test platform starting in 2022. A variety of electrolyzers will be tested in this project. "As a cooperation partner in this initiative, Linde will buy the green hydrogen,” says Dietrich. “We then treat the gas and make it available to our customers.”

Leuna is integrated into one of Germany's largest industrial hubs, connected by an extensive pipeline network and excellent links to the surrounding infrastructure. Hence, it is ideally positioned to support local customers with the full range of industrial gases. "We have also been looking at ways of 'greenifying' other gases besides H2, such as nitrogen or oxygen," Pretz says. With a keen eye towards emerging trends, Leuna is already shaping the hydrogen future. With its industrial-scale electrolysis plant plus its new H2 liquefaction plant, it gives the energy economy all the more reason to "Think Hydrogen. Think Linde."