Hydrogen-based energy systems are gaining increasing attention as the maritime industry moves towards sustainable solutions for onboard power generation. Within the MARPOWER project, LUT University graduate Satu Lehto explored how hydrogen-fuelled gas turbines could support the decarbonisation of marine energy systems. Her thesis offers valuable insights into process optimisation and demonstrates the potential of hydrogen as a clean fuel for shipboard electricity generation and cogeneration.
Interest in hydrogen and path to the MARPOWER project
Satu Lehto holds both a bachelor’s and master’s degree in energy technology from LUT University. She moved to Lappeenranta in 2020 to start her bachelor’s studies and completed them in spring 2023. Later that year, she began her master’s programme, majoring in sustainable energy systems.
Her studies covered a wide range of subjects, including programming, energy conversion, fluid machinery, energy and society, renewable energy and power plant systems. During an exchange semester in Taiwan, she took courses on hydrogen and fuel cells, offshore wind energy, life cycle assessment (LCA) and materials for energy storage, which deepened her knowledge of hydrogen technologies and sustainable energy systems.
Satu learned about the MARPOWER project during one of her master’s courses, when an email was shared about the opportunity to complete a thesis connected to the project. She reached out to Teemu Turunen-Saaresti, Professor of Fluid Mechanics and Head of the Research Group at the Laboratory of Fluid Dynamics at LUT University, and a researcher within the MARPOWER project, who became her examiner alongside Associate Professor Aki Grönman. Although Satu conducted most of the research independently, she greatly appreciated the expert guidance and support provided by her supervisors throughout the work.
Focus on hydrogen in marine gas turbines
While the MARPOWER project explores multiple alternative fuels for gas-turbine-based energy conversion systems, Satu’s thesis focused on hydrogen as the main fuel. The topic aligned closely with her interests and complemented her coursework.
Over a six-month research period, she examined the operation of gas turbines in the maritime context, studying how hydrogen combustion affects system performance. Her work involved linking the turbine and waste heat boiler calculations and analysing how parameter changes influenced the process.
A key part of her analysis was the pinch point temperature difference (PPTD) in the waste heat boiler, as well as the effect of turbine inlet temperature on other parameters. The modelling and data analysis were carried out using Excel, allowing her to connect and compare system components. This work also strengthened her technical and analytical skills.
Key findings and relevance for the MARPOWER project
Satu’s thesis provides insight into hydrogen-fuelled gas turbine behaviour, showing how design parameters affect efficiency and emissions in marine energy conversion systems. Her findings advance the MARPOWER project’s objective of developing cleaner, gas-turbine-based solutions for onboard electricity generation and cogeneration, while supporting ongoing research on alternative fuels for ship energy systems. By linking the turbine and waste heat boiler calculations, her work offers a practical approach to improving energy recovery and process integration in future vessel energy conversion systems.
Learning and looking ahead
Reflecting on her experience, Satu describes the thesis process as a major learning opportunity that deepened her understanding of the maritime sector and its path towards decarbonisation. “The whole six months of doing my thesis included a lot of learning for me. I got to dive deeper into the maritime sector and its prime movers as well as did research on how hydrogen-fuelled gas turbines have been studied and how wide their usage is”, she explains.
Her work received a grade of 4 out of 5 and positive feedback from her examiners. More importantly, it strengthened her motivation to continue contributing to the decarbonisation of the marine sector. “My thesis topic gave me a better understanding of the changes that the marine sector has to face and how decarbonisation is made possible. I definitely want to contribute to this agenda even in the future”, Satu concludes.
Photo by Maria Mattila