Wave energy is created by the movement of the ocean's surface. When a wave rocks a boat back and forth, it's doing work. That energy can be captured and used to generate electrical power.
If harnessed properly, it has the potential to provide 10% of the world's energy needs. The three most common methods to harness wave energy are attenuators, overtopping systems, and point absorbers. The attenuator rig sits upon the ocean's surface, giving it a snake-like appearance.
Each section is connected by a joint that allows the attenuator to undulate along each wave. The movement of the wave pushes and pulls hydraulic cylinders, causing fluids to compress into high-pressure accumulators, creating an electrical current. The attenuator was the first wave power generator implemented for commercial use, and has the capability of powering up to 500 homes per unit. In March 2003, a European team in Denmark launched a floating, 237-ton prototype utilizing an overtopping system. The overtopping works like this.
When a wave approaches the rig, two wave reflectors guide the water to the center and up a curved ramp into the reservoir where the water is stored. From there, it's run through several hydro turbines. The water pressure spins the turbines and the energy is converted into electricity with a magnetic generator.
Overtopping rigs can withstand environmental hazards fairly well. The rig was designed to be large and heavy to combat any rolling and pitching. The low floating and heavy design allows giant winds and waves to simply pass over the rig.
Another way to collect wave energy is using a point absorber. A point absorber works using a buoy that floats above the water to generate power. A giant shaft is anchored to the seafloor with the buoy secured on top. As the buoy moves up and down with the waves, the pumping action is converted into electricity.
A single unit can generate enough power for 40 homes. The next generation is predicted to generate four times that amount. Put them together in a farm and a power plant is born. With further research and development, wave energy just might become a major contributor to the team of renewable energy all-stars.