ERIC KLEIN, Siemens Energy

A groundbreaking green hydrogen (H₂) project for the chemicals industry is proving the case that decarbonizing the sector is possible. Has one of the biggest challenges on the road to net zero been solved?

Decarbonizing industry and shifting sectors like chemicals, steel, petrochemicals and cement onto a carbon-free footing has long been considered one of the biggest challenges to realizing the energy transition in a timely way. A key development is demonstrating that the chemical sector has an opportunity to address its carbon footprint using advanced technology from Siemens Energy.

Evonik, a specialty chemicals company headquartered in Essen in the North Rhine-Westphalia region of Germany, has forged a partnership with Siemens Energy to develop a pilot scheme to produce green H₂ at its site in Herne. Green H₂ is produced using renewable energy and is an attractive approach to existing processes as it can be treated simply as a drop-in replacement for fossil-derived equivalents. The bulk of the world's H₂ is derived from steam reformed natural gas and is therefore associated with substantial carbon emissions.

Today, complex chemicals are produced at the Herne site and the green H₂ produced will be used as a precursor product for isophorone diamine (IPDA). Evonik has been producing this molecule from acetone for many years and this industrial process originated in Herne. However, while in the 1960s, isophorone was sold primarily as a solvent, it is now a much sought-after precursor product for many industries. IPDA is used, for example, to cure epoxy resins and is thus a key raw material used for wind turbine rotor blades.

The Herne location requires significant amounts of H₂ per year for its chemical production. Until now, this has come by pipeline and is fossil-based. However, in a groundbreaking development, Siemens Energy will supply and install its advanced proprietary proton exchange membrane (PEM) electrolyzers that will produce H₂ and oxygen onsite from renewable energy. Unlike some electrolyzer technologies, Siemens Energy’s PEM is well suited for the volatile output that is typical of renewable energy resources. Significantly, the so-called H2annibal project is partially named after the nearby Hannibal mine, which produced hard coal until about 50 years ago. Now it is set to be the home of a system to power the next century of industrial transformation and beyond.

Transforming the chemicals industry. With a rated power demand of 8 MW, the advanced PEM system will supply up to 45% of the H₂ required at this site and the plant’s entire oxygen demand. By deploying renewables to produce green H₂ the H2annibal project is expected to eliminate some 12,000 tons per year (tpy) of carbon dioxide (CO₂) emissions for Evonik. The plan is part of the company’s ambition to make the Herne site climate-neutral under what it calls its Herne Green Deal. As part of this program, Evonik aims to reduce Scope 1 and Scope 2 emissions by 25% by 2030 and this project is an important part of that plan.

The project will allow the partners to not only test a new generation of the PEM electrolysis system but crucially also deploy that as part of an integrated industrial process. H2annibal is therefore set to act as a model for renewable H₂ production for use in a chemical park with real-world fluctuating requirements depending on demand. With this holistic concept at the heart of the program, the Herne plant is set to become a showcase for a decarbonized chemical industry.

Evonik and Siemens Energy begin their partnership on the project at the end of 2022 and construction of the electrolyzer system will start this year. It will be installed in a 100-meter-wide hall previously used to store fertilizer, and the project is scheduled to run until mid-2025.

The Federal Ministry of Education and Research is providing total funding of around €9.3 MM for the project, which will support research into how electrolysis technology responds in industrial use.

Commercializing PEM technology. A key element of the development of the technology is the transition from pilot scale projects to full commercialization which concerns crucial industrialization concepts such as standardization and scaling. Siemens Energy has been particularly focused on its efforts to standardize the PEM system by advancing factors like ease of delivery, a small system footprint, modularization, serviceability and fast-track onsite implementation. The company has as well identified partners in the market which pre-assemble the stacks into the steel frames and arrange all piping. This clear decoupling allows a gathering of key competencies while also addressing bottlenecks which might otherwise exist.

Optimizing the steelwork, piping, cable routing and many other aspects is a big step forward towards a far more compact and commercial design. Taking that next step is critical for widespread industrial implementation across the chemicals industry, but applies equally to cement, steel or any other industry. Across all these industries and every site, each square meter has an associated cost and there is also limited space available. Meeting the requirements for skid mounting, easy transportation, rapid erection and fast-track commissioning are all necessary to achieve short implementation times and widespread industrial uptake.

However, it is also important to recognize the importance of scale when considering the necessary volumes of H₂ needed to completely transform an industrial sector like the chemicals business. This means preparing for a transformation at gigawatt-sized electrolyzer capacities. That in turn requires large assets to be erected to support this transformation, such as electrolyzer production plants. Scale-up thus depends on the production capacity of PEM stacks and this is why the Siemens Energy giga factory plays an important part in the net zero transition.

This plant, located in Berlin’s Moabit district, already can serve a GW demand and is prepared to grow further. The facility relies on automation and robotics to support electrolyzer serial-production, and its development is taking place in partnership with Air Liquide. This joint venture follows on from the so-called Trailblazer project that was also developed in partnership with Air Liquide and featured a single array of 24 electrolyzer stacks and a power demand of 17.5 MW.

Decarbonizing industry value chains. Siemens Energy is already scaling up production capacity in parallel with a focused approach to standardizing and industrializing the design, but there is also considerable effort going towards developing the core technology further. PEM stacks offer high efficiencies and the Evonik project features a more advanced PEM system than that deployed in the Trailblazer project. The Evonik system is a much more compact design and using more advanced materials inside the core element, for example. This design continues the rapid technological development seen in PEM technology, where for instance the efficiency could be increased significantly from the earlier Siemens Energy electrolyzer product Silyzer 200 to the latest Silyzer 300.

Siemens Energy started that process of technical improvement relatively early in 2011 and now the company is already decarbonizing the first showcases in industries and building a wide range of references in the steel, chemicals and mobility sectors. The Evonik project is an example of transforming a former fossil-fuelled industry into a future-looking sustainable H₂ industry, and while IPDA is mainly used in wind turbine blades many more applications can be based around the use of H₂ as a base or pre-product. Ammonia and other products are also manufactured at this site and thus the PEM system from Siemens Energy is helping to transform not just the speciality chemical industry but the entire value chain.

Other similar projects are also in the starting blocks as the industry gathers momentum across both the policymaker set and industrials. Late last year, for example, chemicals giant BASF received funding approval for a 54-MW electrolysis plant that is set to produce up to 8,000 tpy of H₂ at the Ludwigshafen site. The so-called Hy4Chem-EI project will support an annual reduction in CO₂ emissions of up to 72,000 t. The project is funded by Germany’s Federal Ministry for Economic Affairs and Climate Action and the State of Rhineland-Palatinate. As with H2annibal, the Siemens Energy PEM system will be powered using renewable energy sources when it begins operations in 2025. BASF intends to use the H₂ produced primarily as a raw material in the manufacture of its products, in addition to supporting H₂-based transport mobility in the Rhine-Neckar Metropolitan Region.

Such projects signal a lot of learnings and further opportunities for improvement across the entire industry and beyond. Industrial decarbonization is still in its formative years and global deployment of electrolyzer technologies is still in its early phases. However, as the ultimate fossil-fuelled energy-intensive industry, the chemical sector is widely considered the toughest nut to crack. By doing so, Siemens Energy is proving that a decarbonized industrial landscape is possible.