Waves are a free and sustainable energy resource created as wind blows over the ocean surface. The greater the distances involved, the higher and longer the waves will be. Energy is stored in this way until it reaches the shallows and beaches of our coasts where it is released, sometimes with destructive effects.
- Oceans cover three quarters of the earth's surface and represent a vast natural energy resource in the form of waves.
- The World Energy Council estimates that 2TW of energy could be harvested from the world's oceans, the equivalent of twice the world's electricity production.
- In the UK alone it has been estimated that the recoverable wave energy resource exceeds total UK electricity demand
- As a general rule coastlines with an ocean fetch of greater than 400km are suitable, but even greater resources are available between latitudes 300 and 600 in the Northern and Southern hemispheres.
- If less than 0.1% of the renewable energy within the oceans could be converted into electricity it would satisfy the present world demand for energy more than five times over.
The technology involves two basic elements; a collector to capture the wave energy and a turbo generator to transform the wave power into electricity.
The wave energy collectors used in the United Kingdom by Wavegen are in the form of a partially submerged shell into which seawater is free to enter and leave. As the water enters or leaves, the level of water in the chamber rises or falls. A column of air, contained above the water level, is alternately compressed and decompressed by this movement to generate an alternating stream of high velocity air in an exit blowhole. If this air stream is allowed to flow to and from the atmosphere via a pneumatic turbine, energy can be extracted from the system and be used to generate electricity.
Eskom is currently looking into the resource availability of wave power along the east and west coastline of South Africa. The process is to capture wave data and manipulate the data to determine the possibility of investing money into a new generation technology. Recently there have been many utilities world wide that are investing money into similar projects. British Columbia just recently announced the opening of a new wave energy generation system.
Once the resource assessment has been completed and the results are positive, Eskom will be doing laboratory tests on different ocean energy conversion technologies. These tests will enable us to choose the best technology to be used on our coastlines, but this will be done over two to three years.