What is wave power?
First, it is important to explain how waves are created. Wind is caused by differences in temperature due to the solar heating of the earth's atmosphere. When this wind skims over the sea, an interaction is caused in which energy is exchanged between the wind and the sea surface. At first, little ripples arise on the surface. Then, the wind that skims along these ripples causes higher air pressure at the front of the wave than at the back. As a result, the ripples change into small waves.
As this process continues, the waves become higher and the distance between the tops (wave length) becomes longer. The amount of converted energy depends on the wind speed, the time the wind blows over the waves, and the distance it covers. During a wave's voyage, it shapes into a more regular wave, commonly referred to as a swell. At ocean shores, swells are very regular and discernible, even when the sea is relatively calm.
Wave power, then, can be seen as a concentrated form of solar energy. During this process of conversion, the energy is concentrated more and more, up to a power level of over 100 kilowatts per meter of wave front.
What does a wave energy converter do?
Basically, it converts the mechanical energy of a wave into electrical power.
How does the PowerBuoy® work? What is so unique about it?
The PowerBuoy is an offshore wave energy converter, most of which is submerged below the water's surface. Inside, a piston-like structure moves as the PowerBuoy bobs with the rise and fall of the waves. This movement drives a generator, producing electricity, which is sent to the shore by an underwater cable. An OPT "wave power plant" will consist of an array of identical PowerBuoys that are electrically connected to provide the desired power capacity.
OPT's "smart" PowerBuoy utilizes computer-based, proprietary technologies. Technological innovations include: patented electronics systems for control and wave power conversion, patented wave power conversion and transfer systems, unique generating systems that function effectively at low and variable speeds, and a modular construction process.
What is done to assess the environmental effects of putting a system like this near the shoreline?
A comprehensive Environmental Assessment (EA) is prepared before any construction phase of a project begins. Great care is taken with the planning and design phases to ensure there are no negative environmental effects.
How is the buoy anchored to the seafloor?
The PowerBuoy is anchored on the sea bottom using a proprietary anchoring system that avoids damage or threat to the seabed or sea life.
Is any part of the PowerBuoy visible above sea level?
As dictated by local marine regulations, an OPT power plant will have a few PowerBuoys with masts that rise above the surface of the water, with navigational aids attached, such as a radar reflector, day mark, and warning light to help aid mariners in the vicinity.
How deep is the water in which the system is installed?
The buoy is designed to be deployed in approximately 100 - 185 feet (30 - 60 meters) of water.
What are the effects on fishermen in the area?
The presence of the buoys does not cause any significant restrictions to fishing. In fact, the buoys serve as an artificial reef and attract fish and other marine life. In some parts of the world, conventional buoys are deployed to serve as "Fish Attracting Devices".
How will the buoy affect sea turtles and other marine life in the area?
Possible impact on threatened or endangered species in the area by the placement of the buoys is addressed in the Environmental Assessment phase of the project. For example, in Australia an independent study found that the OPT system had no negative impact on sea life, including migratory patterns of whales.
How will the buoy affect swimmers in the area? Will they be electrocuted if they swim nearby?
Although the buoys generate electricity, all the electrical generating and transmitting devices are housed in insulated enclosures, and the standard underwater cable is shielded to prevent stray electrical currents. The system is designed to prevent any loss of electricity or emissions from electromagnetic fields.
What is the impact on the shoreline?
The power is brought to shore by a standard submarine transmission cable. It is brought through the surf zone by conduit and the cable terminator at a standard grid connection box located near the shoreline. There is effectively no impact to the shoreline or to any sea life in the vicinity.