How can we extract as much energy as possible from the movement of the sea? That was the question three upper-secondary students from Aranäsgymnasiet in Kungsbacka set out to explore in their final-year project. At Chalmers’ marine technology laboratory, they used advanced facilities to investigate how different parameters affect efficiency and power output in a wave energy system.The project also gave them a taste of university studies, one that left them wanting more.
The idea of focusing their project on wave power emerged when Ludwig Fahl, Albert Olofsson and Ylva Lorentzon began considering what they wanted to work on during their final year at Aranäsgymnasiet. Early on, they decided to choose a topic related to energy and climate.
Through their supervisor, they were put in touch with professor Jonas Ringsberg, Head of the division of Marine Technology. This gave them the opportunity to carry out their study in the university’s Marine Technology Laboratory (MTL), with support from researchers Per Hogström and Martin Schreuder, and to connect their work to an ongoing research environment. At MTL, they had access to a wave simulator and advanced measurement equipment.
“We had ideas about what we wanted to investigate, but we didn’t know what was technically feasible,” says Ylva Lorentzon. “We met somewhere in the middle - we brought our questions, and they helped us make them workable. We received great support and were able to shape an approach that could actually be tested.”
Focus on three parameters
Their project examined how three factors in a model of a wave energy system - the mass of the buoy, and the frequency and amplitude (height) of the wave - affect the generated power and efficiency.
During a day of experiments at MTL, they placed a buoy in the laboratory’s wave tank. By systematically varying the three parameters, the students were able to identify which factors had the greatest impact, as well as which combinations were most favourable.
“The buoy was anchored to the bottom of the tank so that it wouldn’t drift away, and it had a motion-capture marker attached so that the cameras in the tank could measure its movement,” says Albert Olofsson.
All results and settings were documented, on film and in Excel.
“We filmed from our perspective and simultaneously recorded which values we were using, so that we could go back and review everything afterwards,” says Ylva Lorentzon.
Developed their own Python solution
After their experimental day and data collection at MTL, the students returned to school to analyse their results.
Along the way, they encountered several challenges. One of the first, and biggest, was defining the scope of their project. Wave energy is a broad field, with theory that quickly becomes complex and involves formulas well beyond upper-secondary level.
“That created some difficulties for us at the beginning, when we hadn’t yet communicated much with the researchers,” says Ludwig Fahl. “It took a while before we really pinpointed what we could do and what was important for our particular project.”
A practical challenge arose when they needed to handle the measurement data. Their school did not have access to the same software as Chalmers, which made it difficult to open and process the files.
“We had to write a small program in Python to be able to open the files,” says Albert Olofsson.
What initially seemed like an obstacle thus became part of the learning experience, and solving a concrete problem with their own tools made the project even more grounded in reality.
Unexpected result
The results of their calculations showed that the highest simulated power output was achieved with the lowest mass, the highest amplitude, but with a mid-range frequency.
The explanation lies in the system’s so-called resonance frequency, the frequency at which motion is naturally amplified. By conducting decay tests, where the buoy was released and allowed to move freely in the water until it came to rest, the students were able to calculate it.
“When you are close to the resonance frequency, you get the greatest motion in the buoy and therefore the best energy transfer,” says Ludwig Fahl.
More than a typical school project
The purpose of the final-year project is not to contribute new research, the students emphasise, but to form part of their education. Even so, the opportunity to work in a research environment has meant a great deal to them.
“From the start, we wanted to do something that is actually being researched,” says Ylva Lorentzon. “It felt like we could take our project a step further, and it was a very enjoyable and rewarding opportunity for us.”
The project was submitted this spring and concluded with a larger presentation at Kungsbacka Theatre, in front of other students from the school.
Next stop: Chalmers?
The collaboration with researchers at Chalmers has also sparked their interest. All three are considering engineering studies, though in different fields.
“I’m very passionate about mathematics and almost certain I want to study applied mathematics,” says Ludwig Fahl.
“I’m not completely sure, but something in physics. I’m considering engineering physics, perhaps combined with medical physics,” says Albert Olofsson.
Ylva Lorentzon is considering chemical engineering.
“It has been very enjoyable to be at Chalmers and see how things operate, and even though we will choose different paths, it feels inspiring to have gained insight into this environment.”
Contact
- Head of Division, Marine Technology, Mechanical Engineering