Searching for affordable green hydrogen

Nicoleta Cucu, a PhD student, will combine economics and chemical engineering to make green hydrogen production more economically viable. The project is part of the M20 program, a fund for interdisciplinary PhD projects aimed at solving large problems in and for society.

Text: Wiegert Kaal (Science Communication student at the University of Groningen)

Hydrogen is produced in several ways. The ‘grey’ variant still requires fossil fuels. Although green hydrogen is better for the climate, the price of green hydrogen cannot compete with its grey counterpart (yet). To facilitate the green hydrogen market Nicoleta Cucu is determined to study more economically feasible hydrogen production methods during her PhD.

Green hydrogen is made out of water via electrolysis with renewable electricity. The current power plants in Europe are producing three to four gigawatts collectively, but there are plans to put five- to ten-gigawatt plants into operation by 2030, Cucu says. This means the worldwide capacity of these electrolyser plants is expected to increase almost exponentially, which the PhD student considers an unbelievable development.

If green hydrogen is to compete in price with fossil-based fuels, research like Cucu’s project is needed to make electrolysing plants more economically feasible. Cucu explains the challenge: ‘If you compare the two prices, the grey hydrogen produced from coal is about two-three euros, while the hydrogen produced by electrolysis can range from five to ten euros. The current electrolysis plants are operating on different kinds of subsidies and grants, which makes it important to continuously make improvements to these types of reactors.’

Improving the electrolysis process

There are significant opportunities to improve the water electrolysis process currently producing hydrogen. A common method to make a chemical process more efficient is to use a substance called a catalyst, which lowers the energy required to start the chemical reaction but is not consumed in the process. The PhD student highlights the opportunity to improve energy efficiency. ‘During water electrolysis, there are two main reactions: one at the anode where oxygen is produced and one at the cathode where hydrogen is produced. The reaction at the anode needs more energy input while only producing oxygen ­– a low-value product. Therefore, it is of interest to find less energy-demanding reactions at the anode which can yield more valuable products than oxygen.’

In the upcoming years, Cucu will try to optimize water electrolysis reactor systems in three key ways. The first approach is to improve the efficiency and lower the required energy for the chemical reactions. Another part of Cucu’s research project aims to generate products with higher value than oxygen at the anode, like hydrogen peroxide, a molecule used in disinfectants and rocket fuel. Finally, she will make a systematic comparison between possible reactions that can yield higher-valued products, evaluating what reaction would be more economically feasible.

Using existing theories, Cucu will do electrolysis experiments. Many aspects of the production can be modified and tested, such as the type of chemical reactions, the reactor design, the catalyst and the flow rates for example. All variations should also be evaluated using simulations that calculate the expected revenue of the production method implemented on an industrial scale.

Multidisciplinary project support

Part of the road to more effective electrolysis has already been paved. ‘I am very happy, because I don’t need to start from zero.’ Cucu explains that the research group at the Engineering and Technology Institute Groningen (ENTEG) has a strong background in this topic. For instance, Prof. Paolo Pescarmona, one of Cucu’s supervisors and chair of the ENTEG board, is an expert in green hydrogen production through electrocatalysis. The PhD student has two more supervisors: Dr. Dulce Morales Hernández, from the Faculty of Science and Engineering (FSE), and Dr. Stuart Xiang Zhu, from the Faculty of Economics and Business (FEB). Both are also part of the ENTEG institute.

The PhD project is part of the M20 program, an initiative of the Ubbo Emmius Foundation (UEF) that gives students the opportunity to do a multidisciplinary PhD. Cucu thinks that in the long run, such a multidisciplinary project offers many possibilities for both personal and scientific growth. She and her fellow PhD students will engage with different parts of the industry, and go outside the bubble of their expertise during their research. ‘It is important to see the bigger picture and to apply knowledge from different backgrounds. Studying in such a multidisciplinary environment allows you to learn how to make connections between various parts of the industry. The M20 program equips you with the skills to do just that.’