Renewable Energy Technologies: Wave

Wave goodbye to carbon emissions! Waves have been around since wind, and as such are the tertiary result of energy transmitted to the Earth from the Sun. It has been estimated that 90 million GW of wave power exists on the surface of the Earth’s oceans.

How Does Wave Power Work?

The process is, like tidal power, very simple. Instead of using the movement of water to directly power a turbine, the movement of waves is captured in a chamber. As the wave comes into the chamber, it compresses the air within it, and the subsquent movement of the air then turns the turbine. As the wave recedes, the air flow is captured in the oppposite direction. The turbine then powers a generator to produce electricity.

The Costs and the Benefits

The cost of wave-derived electricity has fallen over the past few years and it can be supposed that these costs will continue to decrease as economies of scale and new technological developments are exploited. It appears that wave power has just about reached the “take-off” point in terms of its economic viability. However, it must be remembered that the power of waves is approximately 35% greater in open sea, than onshore, so developing offshore devices could pay greater dividends. Also, shore-mounted devices need small tidal ranges and are thus better suited to Scottish and eastern coasts than to the south-west and Channel areas. (Source: Boyle G. (Ed) et al, 2004. Renewable Energy: Power for a Sustainable Future. Second Edition. Oxford University Press.)

As wave power is, essentially, concentrated wind energy, it has the potential to flatten-out wind power fluctuations. Also, due to the increasingly accurate prediction of the weather, it may be predictable in its hour-by-hour power potential.

Wave Power in the UK

Despite the fact that UK has considerable coast line, wave power capacity in 2003 was approximately 0.5MW, enough to power around 350 homes. Testing new technology - the Pelamis Sea Snake - at a site in Orkney is underway, and it is hoped that a combination of these ‘Snakes’ will create a wavefarm generating around 30MW of power, or enough for 20,000 homes.