From Vision to Reality — five pivotal years in the history of Topsoe’s SOEC

A future 36 years in the making 

Topsoe’s journey toward commercial solid oxide electrolysis (SOEC) is not a recent development in our history. It began over three decades ago, sparked by a vision to meet soaring energy demand and growing climate concern with smarter, cleaner alternatives. As we celebrate the official inauguration of the EU’s largest SOEC manufacturing facility in Herning, Denmark, we look back at the foundational milestones that defined Topsoe’s SOEC development. Here are five pivotal turns in our journey to industrializing SOEC technology:

1989 – A year of climate reckoning and reaction 

In 1988, following the hottest year since records began, global warming and the depletion of the ozone layer had become increasingly prominent in public debate and political agendas. In 1989, the landmark Ministerial Conference on Atmospheric Pollution and Climate Change took place in the Netherlands. The goal of the conference was to create a binding agreement on CO₂ emissions, which almost succeeded.  

Simultaneously, in 1989, Topsoe began research and development into Solid Oxide Fuel Cell (SOFC) technology, having foreseen the need for alternative fuels in helping address global warming increases, exponential growth in energy demands, rising energy prices and the energy transmission limitations of fossil fuels.  

2004 - Turning R&D into reality 

After strong results and many validated hypotheses throughout initial R&D phases, Topsoe Fuel Cell, a subsidiary of Haldor Topsøe A/S, was founded in 2004. This placed Topsoe at the forefront of developing, manufacturing and marketing SOFC technology. 

Based in Lyngby, Denmark, Topsoe built the extensive infrastructure and facilities needed to develop and explore the potential of this technology. Funded in part by the EU’s Life Program, the Lyngby facility was specifically designed to enable mid-scale industrial manufacturing of SOFC technology - with the primary objective of lowering manufacturing costs. Backed by EU support, our Lyngby facility scaled stack production while collaborating with partners like Wärtsilä, AVL, and Forschungszentrum Jülich. Together, we pioneered distributed generation and auxiliary power units for transport, defense, and off-grid use.  

This facility was not only home to what would become a decade of exemplary work on SOFC research and development, it laid the foundations that would be critical to Topsoe’s shift towards solid-oxide electrolysis.  

2014 - A shift toward electrolysis 

By 2014, our SOFC technology had been tested in harsh real-world conditions—from trucks and buses to ships. We’d proven performance, robustness, and repeatability. The time had come for the next chapter.  

By 2015 funding had been secured for the establishment of an SOEC pilot plant. In partnership with DTU Energy, Aalborg University and DTU Elektro, the project was designed to further improve performance and durability of SOECs and stacks with the ultimate goal of making SOEC technology ready to play a major role in Denmark’s transition to renewable energy.

The main objective of the project was to mature SOEC technology to a level where competitive applications could grow from niche markets to significant segments of the specialty gas and off-grid power storage markets requiring extended storage time. Niche markets serve as stepping-stones for further maturing of the technology, however, challenges related to degradation, robustness and cost had to be solved before upscaling to multi-MW SOEC-based systems was possible.

Significant progress was made on improving degradation and robustness both on cell and stack level: stable electrolysis operation was demonstrated for more than one year, both at the cell level and at stack level; cells and stacks could be operated in a stable manner under grid balancing related conditions, with a realistic wind power production profile. And at stack level, improved gas flow distribution and interface adherence lead to a new stack design, which was implemented in Topsoe stack production.

This level and speed of improvement would have been impossible without the foundations laid by Topsoe’s work in SOFC. In the 10 years the Topsoe Fuel Cell business operated, the company had amassed a wealth of experience and proven their ability to successfully transition from lab scale to commercial scale whilst successfully demonstrating their highly efficient TSP1 stack in numerous pilot projects and demos. 

2023 - From pilot to plant 

By 2023, our vision of a highly efficient high temperature electrolysis process that could deliver industrial-scale quantities of green hydrogen was rapidly becoming a reality. At Topsoe’s test centre in Frederikssund, we successfully demonstrated an entire hydrogen plant powered by our SOEC core. The system achieved ~93% efficiency, used less than 36 kWh/kg H₂, and ramped from 0–100% in just three minutes. This wasn’t a lab test—it was real-world proof that SOEC works at scale.

Topsoe’s SOEC was further validated by the EU Innovation Fund, which invested €94 million to support the construction of our 500 MW/year SOEC stack manufacturing facility in Herning, Denmark. The years from 2023 – 2025 have been defined by the materialization of this facility, watching blueprints and planning transform into a 23,000 m2   size plant with 150 employees on-site. What becomes even more thrilling is knowing that this is just the beginning. Herning’s production capacity is currently set at 500 MW/year, but it designed to expand to 5GW, and while Herning is Tospoe’s first industrial scale stack manufacturing facility, it is certainly not intended to be our last. 

2025 – The official inauguration of Herning's SOEC manufacturing facility

On Oct. 30th, 2025, Topsoe will mark it is most recent and largest milestone in the development of its SOEC technology: the official inauguration of the SOEC manufacturing facility in Herning, Denmark. The years from 2023 to now have been defined by the materialization of this facility, watching blueprints and planning transform into a 23,000 m2   size plant with 150 employees on-site. What becomes even more thrilling is knowing that this is just the beginning. Herning’s production capacity is currently set at 500 MW/year, but it designed to expand to 5GW, and while Herning is Tospoe’s first industrial scale stack manufacturing facility, it is certainly not intended to be our last.

This inauguration additionally offers the opportunity to celebrate the first customers who will be using the SOEC stacks produced from Herning. First Ammonia, a pioneering green ammonia producer, and Forestal, the company behind the innovative Triskelion e-Methanol plant, will both be among the first recipients of Herning’s SOEC stacks, and are essential partners in getting this technology out into the market and ready to make an impact.