Wave Power
Waves are formed by the action of the wind on the surface of expanses of water, in this case we are referring to the oceans. Energy is transferred to the ocean by the wind when it creates these surface waves.
Because the wind is the result of solar energy heating our atmosphere, we can see that wave energy is a sustainable energy resource because it is a form of solar energy!
The wave energy resource around the world is estimated as 2 TW, which is 17,500 TWh (Thorpe, 1999). This is a large resource that is available to be used.
To demonstrate the advantages of replacing fossil fuels as an energy source, an estimate of the saving of the emissions that would have been generated if 2TW of electricity was generated from a coal powered station, produces the following.
3851MW generated from wind power (Wind energy database - UKWED) saves the following emissions from being created:
| emission | tonnes per annum | tonnes per MW | tonnes per 2TW |
| CO2 | 4,329,408 | 1130 | 2,260,000,000 |
| SO2 | 100,684 | 27 | 54,000,000 |
| NOX | 30,205 | 8 | 16,000,000 |
The tonnes per annum is the amount of emissions saved by the use of windpower in generating 3831MW of electricity
(source: UK Wind Energy Database – UKWED BWEA currently operational projects)
The energy in the waves can be captured to do 'useful' work. Wave energy is free but it must be controlled in some way to do useful work which would normally be to operate some device that generates electricity.
There are two basic types of systems designed to harvest wave energy, they are shoreline devices and offshore devices, the names speak for themselves.
Shoreline devices include the TAPCHAN wave energy converter, and the LIMPET oscillating water column. Both of these require deep water close to shore, a tidal range of less than 1 metre and plenty of waves.
Offshore devices include the Anaconda Wave Energy Converter, the Wave Dragon and the Oyster wave energy converter.
Thorpe, 1999 - A Brief Review of Wave Energy, ETSU report R122