Intelligently controlling solar-powered food warehouses and mathematically optimizing interconnected local energy grids powered by renewable energy: These are the goals of Marcy Audrey Demafo and Inezy Remy Mugenga of the University of Rwanda and the Nelson Mandela African Institution of Science and Technology in Tanzania. As part of a university cooperation between Ilmenau University of Technology and the African Institute for Mathematical Sciences (AIMS) in Rwanda, the doctoral students were guests in Ilmenau in the summer 2024. The aim of their research is to contribute to a transformation of the agricultural, food and energy systems in their home country. The Alexander von Humboldt Foundation (AvH) and the German Academic Exchange Service (DAAD) are funding a total of three doctoral students and one postdoctoral researcher as part of the collaboration with funds from the Federal Ministry of Education and Research (BMBF).
“Our continent has changed and developed a lot in recent years and has great potential,” says Audrey. Africa owes this not least to a young, growing population who, like Audrey and Remy, have set out to leverage this potential, address challenges such as the consequences of climate change and secure a stable energy supply.
Droughts as well as floods and soil erosion have increased in Rwanda and other African countries in recent years. Harvests are failing, soils are deteriorating and an unstable power supply for food storage is leading to additional food losses. “This food insecurity means that the rural population in particular is becoming impoverished and suffering from hunger,” explains Audrey.
That's why, as part of the university cooperation between AIMS Rwanda and TU Ilmenau, we are working together to find sustainable solutions to reduce food losses, cut electricity costs and ensure high food quantity and quality.
"The best area for addressing societal needs with rapid, impactful contributions"
Their research focuses on mathematical approaches to optimizing and controlling intelligent systems for renewable energy and sustainable food supply chains, especially in remote areas without a grid connection. Both Audrey and Remy began their research in May 2022, and in the summer of 2024, they visited Ilmenau for the second time to conduct research and exchange ideas with researchers from the Process Optimization department headed by Prof. Pu Li.
“Sustainable process optimization is the best area for addressing societal needs with rapid, impactful contributions,” Remy agrees. While he himself is concentrating on the mathematical optimization of so-called distributed microgrids for a robust power supply in his doctorate, Audrey is investigating how solar-powered food storage systems can be intelligently controlled using mathematical methods to ensure high quality of agricultural products:
Post-harvest chain comprises several steps that start from the crops’ harvest and end with their delivery to the consumers. However, many steps during the process need to be properly monitored and controlled so that consumers end up with a high-quality product. If the farmer is not well versed in this process, it results in food loss, food waste and inferior products. In my work, I am working on optimizing the storage process for agricultural products - this is my contribution to helping the farmers in my home continent.
"Research is always about small steps"
While Audrey and Remy initially dealt with the state of the art in their respective fields during their first stay in Ilmenau in 2022, they are currently spending a lot of time developing suitable algorithms for solving their respective problems. They are being supervised by Dr. rer. nat. habil. Abebe Geletu, holder of the Research Chair for Mathematics and its Application at the African Institute for Mathematical Sciences (AIMS) in Rwanda, and Prof. Pu Li, Head of the Process Optimization Group at TU Ilmenau: “We are currently in the second phase of our doctoral journey and have to deliver our first results,” say both Audrey and Remy:
It's not always easy to motivate yourself: During your doctorate, you're forced to learn things that you didn't know before and that go beyond your own topic. For example, I now have to deal with electronics and learn a new programming language.
"If I didn't love what I do so much, I certainly wouldn't have the energy to overcome these challenges”, emphasizes Audrey. She adds:
I've definitely grown in the last two years and I'm still growing - also because of the good connection with my supervisors. I learned it's normal to get stuck at times. But if you talk about it, you will not get the solution right away, yet at least you get some ideas and directions towards the solution. And that can only be done through discussions and collaborations. Moreover, being surrounded by good people throughout this unique journey of my life is really helping me and keeps me motivated.
Remy continues: “At the beginning, you feel like Superman because you want to solve big social problems. That's really motivating. But once you've started, you realize that research is always about small steps, that is, always adding a small stone to an existing pile of stones.” What he learned is, research is therefore more than just motivation: “It is a formal profession that requires hard work, a lot of perseverance as well as references.”
Both Remy and Audrey have experienced their first participation in conferences in Morocco or Italy where they presented their research results at the 12th IFAC Symposium on Control of Power and Energy Systems and the 22nd World Congress of Food Science and Technology, respectively. In addition to exchanges with international researchers, an alumni workshop and a workshop on model predictive control at TU Ilmenau also helped them to prepare for the next phase of their doctorate work. Remy is enthusiastic:
This exchange with other scientists who love mathematics as much as I do, in one of the best engineering regions in the world, has inspired me a lot and given me a lot of input to continue working on mathematical methods for optimizing the energy sector.
They are expecting the next stay in Ilmenau in the next summer.