How do tidal and wave energy systems differ?

Tidal energy systems harness the power of tidal movements, while wave energy systems utilise the energy from ocean surface waves.

Tidal energy systems and wave energy systems are both forms of marine energy, but they differ in the way they capture and convert energy from the ocean. Tidal energy systems take advantage of the predictable rise and fall of the ocean's tides. They typically involve the construction of tidal barrages, underwater turbines, or tidal lagoons. Tidal barrages are essentially dams built across the entrance of a coastal basin. The tide flows into the basin and is then released through turbines, generating electricity. Underwater turbines work in a similar way to wind turbines, but are driven by tidal currents instead of the wind. Tidal lagoons are a newer technology and involve building a circular retaining wall around a natural basin, which is then filled and emptied by the tides to generate electricity.

On the other hand, wave energy systems capture the energy from ocean surface waves. This can be done in several ways, but the most common is through the use of wave energy converters (WECs). These devices float on the surface of the ocean and capture the energy from the movement of the waves. This energy is then converted into electricity. Some WECs are anchored to the ocean floor, while others are free-floating. The energy captured by WECs is largely dependent on the height, speed, length, and frequency of the waves.

While both tidal and wave energy systems are renewable and have the potential to provide a significant amount of power, they each have their own advantages and disadvantages. Tidal energy is highly predictable, as tides follow a regular and well-known cycle. However, suitable sites for tidal power stations are limited and can have significant environmental impacts. Wave energy, on the other hand, is less predictable but has a much larger potential resource, as waves are generated across the entire surface of the ocean. However, wave energy systems must be able to withstand harsh ocean conditions, and the technology is still in the early stages of development.