Harnessing the Power of Ocean Waves

Clean, abundant, and renewable energy can be harnessed from ocean waves. Waves are created by wind blowing over the surface of the ocean. This stored wind energy can be converted to electric power. A robust variety of renewable energy sources that include wind, solar, ocean, and geothermal technologies will be our best ally in the effort to reduce dependence on fossil fuels. The use of wave power, like other renewable energy sources, can help to displace carbon dioxide emissions brought on by the burning of fossil fuels. Commercial use of wind and solar power has increased significantly over the last decade. Progress in the development of ocean energy technologies, including tidal, current, and wave power has been slower, but the future looks promising.

A number of inspired designs have been proposed for capturing the energy of ocean waves, and many prototypes have been developed. Wave capture devices vary in their method for capturing wave energy. Some are anchored to the ocean floor, while others float or bob on the water's surface. Extraction of the energy in waves requires a system of forces that act in response to one another upon contact with a wave. Point absorbers float on water, and move with the motion of the water, to drive an electromechanical or hydraulic energy converter. Terminators capture wave energy by halting the progress of the wave, and collecting the water, which drives a turbine connected to a generator. Attenuators are long, floating snake-like devices with multiple segments, and an orientation parallel to oncoming waves. Reaction of the device with a wave drives a hydraulic pump, or some other type of converter, to generate electricity. Overtopping devices have turbines installed at the bottom of a collection reservoir. Submerged transmission lines transfer electricity to the shore.

The Aguçadora Wave Park, off the coast of Portugal, supplies power to the country's electrical grid, with three Pelamis P-750 attenuators. Aguçadora will generate 2.25 megawatts of electricity, enough to supply power to approximately 1000 to 1500 homes. Portugal has positioned itself as a leader in the development of renewable energy technologies, and provides incentives for wave power technology development. The Orcadian Wave Farm, under development off the coast of Orkney, Scotland, will utilize four Pelamis machines to generate 3 MW of electricity. Other wave power demonstration and feasibility projects are underway in Europe, South Africa, and North America, with some companies planning for commercial rollout in the foreseeable future.

Wave power has the potential to provide a significant contribution to electrical grids around the world. Perhaps no single source of renewable energy will completely address the world's energy needs; however, a combination of clean energy technologies, including wave power, will help to alleviate the environmental and political concerns surrounding the use of fossil fuels and nuclear power. The energy stored in ocean waves is there for the taking. We can have as much as we want, there will always be more.

References

http://www.carbontrust.co.uk/technology/technologyaccelerator/ME_guide.htm
http://www.pelamiswave.com/