By Christine Ethier (Energy Trace)
Harnessing Wave Energy
Geothermal energy is the energy that comes from heat stored in the ground, whether from the potential energy trapped from the sun in shallow ground or the hot water and hot rock a few kilometers below the earth’s surface or from the molten magma trapped far beneath the earth’s surface.
Harnessing Wave Energy
Scientific opinion supports the idea that we will have to go to the ocean for food if we are to support the newly 7 billion estimate of the world’s population. As well, many believe that both building materials and minerals that our ever growing people’s needs will also come from our sea and our oceans. It will probably not be a surprise to you that our energy needs are beginning to be met by various forms of ocean generated power including but not limited to: wave generated power, current generated power, tidal generated power and offshore solar power.
Wave Generated Power
Waves are caused by the wind blowing over the surface of the ocean. In many places in the world’s oceans, the wind blows with the reliability and force to provide continuous waves that can provide prodigious energy in the ocean waves. Mankind has invented and continues to invent new devices to extract energy directly from the surface motion of ocean waves and even tapping into the pressure variations that occur below the surface.
Ocean Wave Energy Technologies
A variety of technologies are being perfected, some even at commercially viable levels. They are quite promising for those hoping to capture energy from the movement of the ocean waves.
Some technologies are currently being designed to be far-offshore as well as in nearshore and offshore installations. Offshore systems are situated in deep water, usually more than 40 metres deep.
While most wave energy systems are installed at or near the water's surface, they differ in their orientation to the waves and in the method by which they convert the wave energy into other energy forms, predominantly electricity. The examples that follow represent some of those wave energy technologies that are currently in both research and development stages.
One such technology that is installed at right angles to the direction that the waves travel is called a terminator device. These capture or reflect the magnitude of the waves and are usually onshore or nearshore. This is because one part of the device must remain fixed and unmoving while another part, attenuators, use long multi-segment floating structures oriented parallel to the direction of the waves that move in interaction with the waves. Currently, floating versions have been designed for offshore applications and usually these must be attached at some point to the sea floor.
Environmental Considerations and Obstacles to WEC’S
Potential environmental considerations for the development of wave energy include the following:
- Positive or negative impacts on marine habitat;
- Toxic releases from leaks or accidental spills of liquids used;
- Visual and noise impacts above and below the water surface;
- Conflict with other sea space users, such as commercial shipping and recreational boating;
- Cost in comparison to oil, natural gas, wind and solar;
- Durability of the component parts;
- Estimated as being able to produce only 10% of the world’s require energy;
Despite all the obstacles and the fact that many of the devices are in their R&D infancies, there is much energy promise from the ocean’s waves.Top