There is a concentrated silence in the room with its many large glass and steel cabinets. Two researchers in white coats are busy reading results on a PC screen. In each of the large rigs, as the cabinets are called, there is a microscope used to characterise electrolysis cells. Or rather, to characterise a single detail in the cells.
Electrolysis cells can convert electricity from, for example, solar and wind energy into hydrogen using water and are an important part of power-to-x, which is a basic element of the green transition.
The laboratory is one of a total of five sub-laboratories that DTU uses to conduct research into electrolysis cells. It may not be obvious to the casual visitor, but this is one of the world's most advanced laboratories in this field. Not only because of the microscopes, but especially because of the knowledge that has been developed over the years, enabling the laboratory to be used for the latest and most advanced analyses.
Together, the five laboratories cover the entire value chain behind the manufacture of electrolysis cells and their application. They investigate new alternative materials and production methods, the electrochemical properties of the cells, their durability and mechanical properties, including how much stress the cell can withstand before it breaks down.
From fuel to electrolysis
Part of the laboratory's work is carried out in close collaboration with Topsoe. This collaboration began more than 20 years ago. At that time, the focus was not on electrolysis applications, but on fuel cells. These are a type of converter that converts chemical energy in a fuel – for example, hydrogen – directly into electricity and heat. The vision at the time was that small fuel cell systems would be present in every home, supplying households with energy from sources such as natural gas.
However, the idea never caught on, as it became too expensive to produce the household systems. Suddenly, the energy agenda changed, and the focus shifted to replacing fossil fuels with more climate-friendly alternatives. The function was therefore "reversed" to become an electrolysis cell, where the reverse process takes place, i.e. green electricity is added to the electrolysis cell, which splits water into hydrogen. Hydrogen can be further converted into green fuels and chemicals that can be stored for later use. This could be for fuel in aircraft and ships or other products.
"Electrolysis cells and the subsequent power-to-x production are crucial to the success of the green transition. The electrolysis cells we have developed together with Topsoe are based on SOEC technology – Solid-Oxide Electrolysis Cell – which is one of several technological options for electrolysis. SOEC technology is the most efficient, i.e. the technology that uses the least amount of electricity to produce hydrogen," says Professor Henrik Lund Frandsen, DTU.
The most efficient technology for electrolysis cells
The electrolysis cell uses 25% less power to convert electricity into hydrogen than other electrolysis technologies.
"This not only affects the efficiency of hydrogen production but also leads to savings in all other parts of the chain. This means that 25% fewer wind turbines or solar cells need to be produced, along with the land for them, cables, transformer stations, etc., to ensure the power-to-x process. These are significant savings, both economically and in terms of materials used. These savings have a major socio-economic impact on when and how easily we can implement the green transition," says Henrik Lund Frandsen.
And hydrogen from power-to-x is crucial if we as a society are to find replacements for fossil fuels for heavy traffic, among other things. Part of shipping and air traffic that serves long routes and therefore cannot be connected to electricity or would require excessively large batteries needs new green fuels, just as the production of plastics, paints, medicines and much more today also depends on fossil fuels. Here, hydrogen is an important piece in the puzzle of finding new alternative solutions.
Continued collaboration to optimise electrolysis cells
Topsoe is building a factory in Herning to produce electrolysis cells that Power-to-x plants can use to convert electricity into hydrogen. The first successful test productions have been completed, and the plan is to have the factory fully operational by 2025.
The collaboration between DTU and Topsoe has been ongoing for many years and has covered many different fields.
"Our collaboration with DTU is older, broader and more long-term than the collaborations Topsoe has with other universities. The collaboration has involved the development of first fuel cells and later electrolysis cells. In addition, we have collaborated on the development of cells in stacks, i.e. stacks of cells on top of each other to increase the effect," says Sune Dalgaard Ebbesen, Group Manager, Tech Scouting & Research Funding, PtX Topsoe.
The focus is now on optimising the electrolysis cells. This involves modelling, design, testing and development of new materials that make the electrolysis cells more efficient. In addition, the goal is to prevent the degradation of the fuel electrode, which is currently a challenge for the technology.
"Together with DTU, we can think outside the box. See what opportunities there are, just as we gain some skills that we don't have ourselves. We have recently achieved promising results that can contribute to a new generation of electrolysis cells to be produced at the factory in Herning in 7, maybe 10 years. At least, that is the prediction of the DTU researchers. Before then, however, we need to conduct thorough testing of the potential of the new electrolysis cells before we put them into production," says Sune Dalgaard Ebbesen.
In addition, the collaboration focuses on gaining a greater understanding of electrolysis cells.
"There are no textbooks on the technology behind the SOEC electrolysis cells that Topsoe has chosen to produce. Over the years, we have conducted many experiments and found that the cells work, just as we naturally know the basic theory behind them. However, we would like to gain a greater understanding of the details, why and how the individual processes and materials in the electrolysis cells behave," says Sune Dalgaard Ebbesen.
Henrik Lund Frandsen agrees and emphasises that such fundamental knowledge will also make it easier to develop and optimise the electrolysis cells in the future. And it is precisely this characterisation and associated modelling of electrolysis cells that the researchers are working on in the world-class laboratory at DTU.
