FWR Group Sustainability Articles
Where is wave energy used?
Wave power is the capture of energy from surface ocean waves for either the generation of electricity, desalination plants or water pumping. Waves produce a huge amount of energy and they have the potential to become a viable source of energy in the future. Wave power is not widely used to date, but there are several active testing programs operating in different parts of the world. As the technology advances, wave energy may well provide a reliable renewable energy source.
There are several different types of wave energy generating devices which can be located on coastal, offshore and even far offshore sites. While all devices are installed on or near the water’s surface, their orientation and manner in which they convert the waves to energy differs. The following devices are currently being used in different locations.
Terminator devices, point absorbers, magnetic linear generators and overtopping devices are all being trialled by various companies around the globe. In Australia, a desalination plant is using point absorbers consisting of a single piston pump attached to the sea floor, with a float tethered to the piston. As the float rises and falls due to wave action it generates pressurised water which is then piped back to the facility on shore to drive the desalination process.
Agucadoura in Portugal is the world’s first wave farm producing electricity commercially. It has three floating Pelamis machines generating 2.25 MW. Enersis, the company running the wave farm have indicated they would like to increase output to 20 MW in the near future. Pelamis machines or attenuators are long multi-segmented floating structures orientated parallel to the direction of the waves. Differing wave heights along the length of the device result in flexing where each segment connects, and this movement is connected to hydraulic pumps or other converters.
Although this type of energy is renewable are there are some possible environmental issues associated with its use. The marine environment could potentially be affected by the installation of these devices. Some devices also contain hydraulic fluids that could be released into the water column. Wave energy devices also pose a threat to marine craft, and they could disrupt fishing grounds for commercial fisherman. While the risks are relatively minor, the uptake of wave energy will still remain fairly slow within the next few years. Cost of installation and unpredictable oceans are the major hindrance to commercially viable wave power farms.
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This work by Michael Duggan is licensed under a
Creative Commons Attribution-No Derivative Works 2.5 Australia License.
