Rachel Maier: Courageously moving forward: taking the step toward starting a business
While still working on her doctoral thesis, Rachel Maier took the plunge and founded a company—together with her master's thesis supervisor, among others. In this interview, the expert in mathematical optimization of energy systems explains how the company was founded and what her responsibilities are at the start-up Twinetic.
Ms. Maier, as the co-founder of a start-up while still working on your doctorate, you have not followed a conventional career path. Your work involves the mathematical optimization of energy systems – another field that is not exactly mainstream. How did you end up in this rather unusual branch of research? For my master's thesis, I transferred from the German Aerospace Center to the Technical University of Darmstadt, where I studied energy science and engineering. Among other things, I took a course in energy management and optimization, which involved mathematically optimizing energy systems. I was fascinated by programming and mathematical optimization from the very beginning! For my master's thesis, I wanted to delve deeper into the subject matter, which is how I ended up at the start-up greenventory in Freiburg, which is affiliated with Fraunhofer ISE, where I immersed myself in the field of mathematical optimization. The interesting thing is that all the solutions I implemented came from publications by Forschungszentrum Jülich. Although I didn't actually want to do a PhD, I enjoyed combining energy systems and mathematical optimization so much that I decided to do a PhD in 2021 after all: at Forschungszentrum Jülich.
So you basically did a PhD on your favorite subject?
Yes, you could say that. I did what I enjoy most at the research center: mathematical optimization. More specifically, I looked at the transformation of the entire energy system from 2020 to greenhouse gas neutrality in 2045. What is the most cost-effective path? When should you invest in which technology? I also helped to further develop the framework of our institute, IEK-3, now ICE-2 – in other words, the programming framework – from Perfect Foresight to budget calculation to the transformation path.
Now you are co-founder of the start-up Twinetic and head of research and development. How did that come about?
During my master's thesis at TU Darmstadt, I was supervised by Christopher Ripp. He had the idea to start the company and drove it forward. I was already sitting in the mathematical optimization lecture taught by Christopher with the rest of the Twintetic team. Back in 2023, the team approached me to ask if I wanted to join them and take on the area of timetable optimization – so the start-up developed in parallel with my doctoral thesis. However, my initial focus was on completing my doctoral thesis. As a founding member, I was involved from the very beginning, and at the end of 2024, I joined the company full-time.
What does Twinetic do?
We develop intelligent software for operational energy management. At its core is a digital twin of the respective system, including electricity, heating, cooling, gas, and compressed air. Energy data is collected, processed, and intuitively analyzed, and then automatic reports are generated. We have integrated intelligent features such as forecasts, anomaly detection, and schedule optimization. When it comes to energy management, the industry has enormous potential to catch up: depending on the company, savings of around 20 percent are entirely realistic, and according to some sources, the energy consumption of German industry could even be reduced by up to 40 percent. For the market launch, we are focusing on the white label solution: we are foregoing our own branding and allowing other companies to add our solutions to their portfolios incognito. We hope that this will enable us to place our solution in conservative companies. In my opinion, this speaks in favor of Twinetic: we work for the purpose and not for our name.
What are your responsibilities at Twinetic?
I head up the research and development department—but as is usual in a start-up, I also do a lot of other things, from financing rounds to sales structures and partner management. Since we only have six employees so far, the founders also have to take on many different tasks. The workload is very high and usually everything comes at once, so it's very challenging. But it's also a lot of fun!
How did your time at the Jülich Research Center prepare you for all these tasks?
The JuDocS courses, which you had to complete alongside your doctorate, were extremely helpful: the content ranged from how to give a presentation to training in leadership skills. The conference experiences are also valuable—they help me enormously with pitching and presenting. There was also a course on starting a business, but I didn't take it at the time: I got into founding a company because of my professional interest, rather than because of an interest in start-ups per se.
Is there anything you particularly liked about the research center?
I particularly liked the infrastructure: during my doctoral studies, I had every opportunity to develop my topic. I also had great support, my supervisors were outstanding! The camaraderie among colleagues was also strong, there was a very supportive atmosphere among the doctoral students.