The electrolyzer
Electrolysis, the method of splitting water molecules into oxygen and hydrogen, has once again attracted a lot of attention in recent years. In 2022, hydrogen is an attractive alternative to natural gas, one of the fossil fuels we no longer want to depend on in the future. But we didn't really want to reduce our use yet. The costs of electrolysis were the sand in the engine of that transition because they made hydrogen extracted from it very expensive compared to fossil fuels. But in recent years, natural gas has become more expensive. In 2021, the price already skyrocketed. And in 2022, a geopolitical motivation was added. One of the largest suppliers of natural gas, Russia, invaded Ukraine. As part of the sanctions, several countries decided to further and/or accelerate their dependence on natural gas. And one of the advantages of hydrogen is that it can in principle be made anywhere in the world so that we are no longer dependent on a few countries that can supply natural gas.
Not further developed
Thijs de Groot is researching ways to bring the electrolyzer as a system into the 21st century. Thijs: “It is a wonderful technology that was developed and applied on a large industrial scale a hundred years ago. The problem is, it feels like we're still driving a 1900 Model T Ford because the technology hasn't changed much since then. Until about ten years ago there was simply little incentive to modernize the electrolyzer. Almost no electrolyzers were built: if you generate electricity from gas, it makes no sense to make gas from electricity. But that has now changed because we really want more green fuel and green raw materials for the chemical industry. Electricity from the sun and wind will go a long way in the energy transition, but electricity alone will not get you there. There will always be a dependence on gaseous fuels. That is why we want to give the electrolyzer a serious update.”
Hydrogen cars are a niche product
Several car manufacturers have already made a model that runs on hydrogen and a few have even launched it on the market. But refueling with hydrogen is not nearly as self-evident as regular refueling or, for example, fast charging. Thijs also sees little benefit in hydrogen-powered cars: “The efficiency of a traditional combustion engine is low: around 30%. And if you build systems in cars that generate electricity with hydrogen, the efficiency is not much higher; about 40%. While with an electric car as we know it now, 90% of the energy goes directly to the wheels.”
Natural gas to the background
According to Thijs, we will eventually be able to do without fossil natural gas, but before that, we can reduce its use with the help of hydrogen. For many companies that depend on gas, oil or coal for their production, hydrogen is an excellent alternative. Thijs: “For example, steel production or the fertilizer industry. But there are also many houses in the city center that are not or hardly well insulated. If you want to get rid of natural gas, you have a great alternative in hydrogen. Our gas pipelines are basically suitable for this. Although we will have to adjust elements, such as the compressors.”
The overloaded network
Our grid is near the edges of capacity. Solar panels are the norm, increasing the supply, but especially at times when we don't need them. Companies also cover their roofs with solar panels. On Sundays, the price per kWh is sometimes even negative. The sun does not always shine when there is a high demand for electricity and vice versa. Our electricity grid has difficulty with that mismatch and we now see that those companies simply cannot access it anymore.
We need storage and there are different methods. Storing electricity directly is getting better, but batteries do not lend themselves to long-term storage. Thijs: “Hydrogen is easier to store. Just like natural gas. And later you use it to generate electricity again. Regional or local. In this way, hydrogen helps us to use energy and its distribution more smartly. “
Simple yet complex
Essentially, an electrolyzer splits water molecules. That description and the basic operation sound simple enough: immerse two conductive metal strips in an (alkaline) liquid and connect an energy source to it. One of the pins (the cathode) attracts positive ions. The other (the anode) does the same with the negative ions. Hydrogen is formed at the cathode and oxygen at the anode. Collect the bubbles with hydrogen and let the oxygen go. Or capture it and use it in processes or products in which it is an essential component.
But he explains the biggest challenge for Thijs and his team: “We know that it works, but we don't yet fully understand how. This makes it difficult to find ways to increase efficiency.” That's why the team spends a lot of time testing electrolyzers and the components they contain. Their workspace has several sizes and types of electrolyzers. Thijs: “We see it as a puzzle and we try to understand every part. It's experimenting, looking at the results and asking ourselves, 'Do we now understand what happened?'”. We have a major advantage at TU/e: an electrolyzer is a system in which many areas of expertise come together. And on our campus, you will find many, if not all, of those areas of expertise.
Theories
There are theories about what should make an electrolyzer better. For example, it is suspected that the gas bubbles created in the process drive the same process into the wheels. Thijs: “But the problem with this is that you hardly see anything about the formation of the bubbles. It looks more like a raging river. You only see a lot of white there.”
There also seem to be gains in the electrodes in particular. Cathodes and anodes in an electrolyzer are often made of rare metals. And that's one of the reasons electrolyzers are expensive. The focus is now on finding an efficient anode that does not contain rare metals. Thijs: “We are now comparing new materials using different spectroscopic techniques.”
HyScaling: A special project
Thijs participates in the Dutch HyScaling project. HyScaling is one of the many projects worldwide for the modernization of the electrolyzer. But this project is unique because of the combination of the parties involved: it is a special mix of expertise, both from the field of fundamental research and industrial practice. Thijs: “And that provides an ideal basis for further developing the technology and building a sound commercial foundation.”