Researchers from the Universidad del Norte in Colombia jointly with their colleagues from the Autonomous University of Campeche in Mexico have tested a new way to generate energy from sea waves. They made an oscillating buoy with a flywheel that transforms the rise and fall of waves into a stable rotation of the generator. This discovery has great potential: the ocean is capable of producing up to 2.15 TW of energy per year, which is comparable to the generating capacity of dozens of nuclear power plants.
The working principle of the oscillating buoy is simple: a cylindrical float with a diameter of 0.2–0.8 m rises and falls on the waves, transmitting the movement through its mechanism to the flywheel. The flywheel smooths out jerks, accumulates kinetic energy and provides uniform rotation. As a result, chaotic oscillations of water turn into a stable flow of mechanical power, which can be transmitted to the generator.
In order to test the device, the scientists performed a trial on a scaled-down model in a 15 m x 9 m pool in Campeche, creating waves with a height of 0.02 m to 0.40 m and a period of 1 to 6 seconds. The movement was filmed with a high-speed camera, and the results were compared with a computer model in OpenFOAM. The match was almost perfect, with an error of less than 1%.
The researchers found that the buoy works especially well when its own rhythm coincides with that of the waves, i.e., when it is in resonance. In this mode, power increased more than threefold, from 15 W to 47.6 W (on the scale of the model), and efficiency reached 35%, which is quite high for systems of this type.
The experiments revealed clear patterns. When waves rise higher, the device produces more power in an almost direct correlation: for instance, a height increase from 0.08 m to 0.16 m causes the output to double. At the same time, relative efficiency decreases: under the same conditions, the energy capture coefficient drops nearly by half due to turbulence and internal losses.
The size of the buoy is also crucial. A small buoy with a diameter of 0.2 m shows better results with moderate waves. A large buoy with a diameter of 0.8 m is better in a storm, although its efficiency suffers.
The chief conclusion drawn by the researchers is that there is no universal design. Units need to be adjusted to specific sea conditions in order to reach profitability. In the Caribbean, where waves usually reach 2–3 m, small buoys designed for an oscillation period of about 8 seconds are optimal. Large and stable units are better suited to the Atlantic and northern seas, where stronger waves are common.
Overall, the Colombian and Mexican scientists have once again proven that seas are an enormous source of untapped energy and that we need to take into account the rhythms of specific currents and coasts to generate electricity.
