Ocean waves carry enormous amounts of clean, renewable energy. Unlike sunlight and wind, the sea is almost always moving, making wave power an attractive source of electricity.
However, one major challenge has limited the success of many wave energy devices: they often fail to move in harmony with the waves, reducing the amount of energy they can capture.
Now, researchers from ESPOL, Stevens Institute of Technology, and several partner institutions have developed a simple solution that could improve the performance of these devices without using complex electronics or expensive control systems.
Their study, published in Energy Conversion and Management: X, introduces a passive design that uses underwater cones attached to a floating platform.
Instead of relying on computers or motors to constantly adjust the device, the new approach lets the natural movement of water do most of the work.
The wave energy system works by allowing a floating platform, similar to a barge, to rock from side to side as waves pass underneath it. This rolling motion is then converted into electricity.
The researchers attached upside-down cones beneath the platform on both sides. As the platform moves, the cones trap and move water around them. This changes how the platform behaves, making it act as though it is heavier and increasing the water’s resistance to its motion.
These changes allow the platform to better match the rhythm of long ocean swells, helping it absorb more energy from the waves.
To test the idea, the team built a scale model that was one-fortieth the size of a full-scale device. They placed it inside the Davidson Laboratory wave tank at Stevens Institute of Technology, where they could create controlled wave conditions.
The researchers compared a platform without cones to four different versions fitted with cones of various sizes and positions. They measured how stable each design remained, how it moved with the waves, and how much energy it could potentially capture.
The results were encouraging. The underwater cones more than doubled the platform’s natural rolling period, allowing it to stay in sync with longer waves that many existing devices struggle to use effectively.
Importantly, the cones did not make the platform less stable. Although they increased water resistance, the added resistance helped improve wave response without causing excessive energy loss.
One of the tested designs achieved an energy capture efficiency of 52% under regular wave conditions. Even when tested in irregular waves that better resemble real ocean conditions, the same design maintained an efficiency of about 21.5%. This suggests the technology could continue working well even when the sea is constantly changing.
The researchers say this is one of the first experimental demonstrations showing that simple underwater structures can significantly improve the performance of wave energy devices.
Although the technology is still in the research stage, the team believes it could eventually provide a low-cost and reliable option for coastal and island communities where maintenance needs to be simple and dependable.
Future work will focus on improving the cone design, testing larger systems, and developing equipment that can efficiently convert the platform’s motion into electricity. If successful, this straightforward approach could help wave energy become a more practical part of the world’s growing clean energy supply.
