4 minute read • Graham Lumley • Last update March 2024
Wave power harnesses the ocean’s waves to generate power by converting waves’ kinetic energy into electricity. Wave power is based on interaction between ocean waves and energy converters, specifically engineered to harness wave energy. The kinetic energy produced by the waves drives turbines, which then generate power that can be converted into electricity.
The conversion of wave energy into electricity involves various methods and technologies, including the placement of devices on or just below the water surface, as well as anchoring devices to the ocean floor. This is a form of renewable and sustainable energy that is often overlooked but with immense potential.
Ocean waves offer more than just recreational value for surfers. They represent a tremendous source of energy, generated by the motion of the waves, which is caused by wind movement across the open water surfaces in oceans and lakes.
Wave energy systems capture this energy, converting the kinetic power of these waves into electrical energy using a wave energy converter. Imagine the vast expanse of the ocean, every wave a potential source of clean, renewable energy, waiting to be harnessed by wave energy technologies.
Although tidal and wave energy both belong to the category of ocean energy and hydroelectric power, they possess notable differences. Wave power involves harnessing the energy from the movement of ocean waves, whereas tidal energy relies on the energy generated by gravitational forces of the Sun and Moon.
Tidal turbines and tidal barrages serve to capture tidal energy, whereas wave energy employs devices such as oscillating water columns, point absorbers, and terminators to transform wave energy into electrical power. Despite their differences, both sources of energy continue to play a crucial role in our quest for renewable energy sources.
Wave energy devices are the tools that allow us to effectively harness wave energy by transforming the kinetic energy of waves into usable electricity.
These devices, like point absorber buoys, oscillating water columns (OWCs), and overtopping devices, each have unique mechanisms for capturing and converting wave energy. Let’s examine these devices in more depth, uncovering the process through which they convert ocean waves into a renewable energy source.
Imagine a buoy bobbing in the ocean, rising and falling with the waves. This is more than just a floating device; it’s a point absorber buoy, a device designed to generate electricity by harnessing the energy of ocean waves.
These buoys use a floating cylinder to capture the vertical movement of waves, which is then harnessed through a cable anchored to the seabed. This up and down motion is subsequently transformed into electricity via converters such as alternators, linear generators, or hydraulic systems.
Another intriguing wave energy device is the Oscillating Water Column (OWC), a device that uses wave power to generate electricity. These devices use the rise and fall of waves to compress air, which then drives a turbine to produce electricity.
As the waves rise and fall, the air in the column is forced to move, creating a strong air flow that can power turbines.
The last of the wave energy devices we’ll explore are overtopping devices. These devices harness wave energy by allowing waves to flow into a reservoir, which then releases the water through turbines to generate electricity.
Factors that can influence the efficiency of overtopping devices include:
Despite potential drawbacks, such as lower energetic wave content compared to other converter types, overtopping devices offer a promising approach to harnessing wave energy.
Despite the significant benefits of wave energy, we must also take into account its potential environmental impact. Although it is generally considered a clean energy source with no greenhouse gas emissions, wave energy conversion can affect marine habitats,
However, concerns remain about potential impacts of wave energy converters, including:
Wave energy presents an attractive opportunity in the renewable energy sector, theoretically possessing the capability to fulfill a substantial part of global power requirements. With wave energy development on the rise, it offers reliable and steady power generation, enhancing predictability in energy supply.
Nonetheless, the journey towards harnessing wave power is not devoid of obstacles. High costs, complex design requirements, and technological constraints are some of the hurdles that wave power development faces. More specifically, operating technology in the sea is difficult due to the corrosive nature of salt water (which damages the metal), barnacles can grow on the equipment and impact performance, and once the electricity is generated, it needs to be transmitted somehow. Transmission from the ocean is very expensive.
Despite these challenges, the potential of wave energy remains largely untapped and holds immense promise for our renewable energy future.
In comparison with other renewable energy sources, wave energy exhibits its own distinct set of pros and cons. While it offers a more dependable and consistent output compared to wind energy, it also comes with higher initial costs and the requirement for effective energy converters.
Despite these challenges, wave energy holds potential cost benefits over solar and wind energy. However, its adoption is currently less widespread, and it faces technological obstacles in expanding on a significant scale.
Wave power extends beyond theoretical concepts, manifesting itself in practical, real-world applications. Some examples of wave power projects include:
