Researchers Develop Engineering Methodology to Improve Wave Energy Converter Testing

Ocean waves represent one of the most consistent and predictable renewable energy resources available, yet wave power technologies remain far less mature than wind or solar systems. A key reason is the absence of standardized engineering approaches during early development stages. A new study led by Assistant Professor Maha Haji at the University of Michigan College of Engineering proposes a structured prototyping framework for wave energy converters that could help accelerate research and reduce repeated design mistakes across the field.

Vitale, O., McCabe, R., Brundan, A., Mandalam, Y., Alonso Munera, A. S., & Haji, M. N. (2026). Design, Build, and Analysis of Small-Scale Wave Energy Converter Prototypes. Journal of Mechanical Design, 148(9). https://doi.org/10.1115/1.4070757

The work, brings together researchers from the University of Michigan, Cornell University, the Georgia Institute of Technology, and Princeton University. The team developed a standardized methodology for designing and testing small scale wave energy converter prototypes. By consolidating fragmented design practices into a unified process, the researchers aim to make laboratory experiments more consistent and easier to reproduce across institutions.

Maha Haji at the University of Michigan College stated,

“We are driven to use the vast ocean resource to create sustainable power for humanity. Wave energy has been long overlooked. It is predictable, constant and 100 times more power dense than wind. It is time we advance this technology past benchtop testing.”

Wave energy has long been recognized as a potentially significant contributor to renewable electricity generation. Unlike wind and solar power, which depend on weather conditions and daylight cycles, ocean waves are relatively stable and predictable. Estimates suggest that coastal waters in the United States alone contain enough extractable wave energy to meet roughly one third of national electricity demand if the resource could be efficiently harnessed. Despite this potential, engineering challenges have slowed the technology’s progress toward commercialization.

One of the major obstacles has been the diversity of wave energy converter designs. Unlike wind turbines, which have largely converged around a standardized three blade rotor configuration, wave energy devices exist in many different forms. Individual research groups often develop their own prototypes without shared design guidelines. As a result, lessons learned in one project are not always transferred to others, and new teams frequently repeat the same early stage mistakes.

The research group sought to address this gap by creating a design process specifically for small scale experimental systems. The team designed and tested two representative wave energy converter prototypes. The first was a heaving point absorber, a buoy like device that moves vertically as waves pass. The second was an oscillating surge converter, which rotates around a hinge as waves push against it. Both systems were anchored to the seafloor through mooring systems and connected to a power take off mechanism that converts wave motion into rotational motion suitable for electricity generation.

Developing a prototype begins with determining the physical constraints of the testing environment. In this case, experiments were conducted at the O. H. Hinsdale Wave Research Laboratory at Oregon State University, which has a maximum water depth of 137 centimeters. The dimensions of the testing facility influence wave characteristics, hydrodynamic forces, and the scale at which experimental models must be built.

To ensure the prototype accurately represents real ocean conditions, the researchers applied Froude scaling. This technique is commonly used in fluid dynamics when gravitational forces dominate the system. Under this approach, the team selected a scale of one to fifty, meaning a one meter laboratory prototype represents a device approximately fifty meters tall in full scale operation. Scaling the system correctly ensures that wave forces, buoyancy, and motion dynamics remain physically consistent with real ocean environments.

Once the scale is established, the converter must be designed to resonate with incoming waves. Resonance occurs when the natural motion of the device aligns with the frequency of the waves, allowing the system to capture more mechanical energy. Achieving this alignment requires careful tuning of the device’s mass distribution, geometry, and mechanical components. The mooring system also plays a crucial role. It must secure the device in place while allowing the converter to move naturally with the waves. If the mooring restricts motion too strongly, the system’s energy capture capability can be reduced.

Small scale prototypes present additional engineering challenges. Mechanical friction becomes proportionally larger as systems shrink, which can reduce the accuracy of energy conversion measurements. To address this issue, the researchers selected a rack and pinion power take off mechanism. In this design, a toothed bar engages with a rotating gear to convert linear motion into rotational movement. The same principle is widely used in vehicle steering systems and is known for relatively low friction and mechanical simplicity.

Electrical measurement also becomes more difficult at small scales. Laboratory prototypes typically generate only milliwatts of electrical power, which is often below the resolution of standard motor controllers. To improve measurement accuracy, the research team incorporated a programmable controller capable of recording electrical current in real time. This approach allowed the researchers to track small variations in generated power and evaluate system performance more precisely.

By organizing these engineering considerations into a step by step framework, the team created what they describe as the first comprehensive design methodology for small scale wave energy converter prototyping. The approach centralizes previously scattered knowledge about scaling laws, resonance tuning, mooring design, and measurement techniques. According to the researchers, standardizing these early stage development processes will allow future teams to focus more on improving device performance rather than troubleshooting common experimental problems.

The broader goal is to help move wave energy technology beyond laboratory demonstrations toward practical deployment. Standardized design practices have played an important role in the development of other renewable technologies, particularly wind turbines, where decades of experimentation eventually converged on a widely accepted design structure. Researchers hope that similar convergence may occur in wave energy systems once more consistent engineering frameworks are adopted.

While wave energy remains an emerging field, efforts like this highlight the importance of engineering methodology in technological progress. By establishing common design principles and experimental practices, researchers may be able to shorten development cycles and build a stronger foundation for future ocean based renewable energy systems.