Marine renewable energy, comprising wave and tidal energy, is a massive untapped resource in the UK. Europe holds 20% – 30% of global tidal resources, 80% of which is located in and around the coastlines of the UK and France. Estimates suggest that, if fully exploited, wave and tidal power could supply at least 10% of the UK’s electricity.
Marine energy broadly comes from two sources:
The power of the waves is readily visible on nearly every ocean shore in the world. Much research has gone into developing technologies to harness the power of these waves energy and transform it into electricity for domestic and commercial use.
These technologies fall broadly into three categories:
- Machines which channel waves into constricted chambers. As the waves flow in and out of the chamber, they force air in and out of the chamber. These airflows are in turn channelled through a specialised turbine, which is used to drive a generator.
- Fixed or semi-fixed machines which utilise the pressure differential in the water that occurs at a submerged point as the wave passes over that point. The pressure differential is used by a variety of means to cause a fluid to flow in a circuit, which is then used to drive a turbine and generator.
- Machines which utilise their buoyancy to cause movement in a part of the device as it moves up and down in the wave. The movement is used either directly or indirectly to drive a generator.
Tidal Energy consists of Tidal Range Energy and Tidal Stream Energy. Tidal Range Technology uses technology to generate energy from a tidal stream and is usually deployed in areas where there is a high tidal range. Typically a barrage with turbines is built across an estuary or a bay. As the tide ebbs and rises, it creates a height differential between the inner and outer walls of the barrage. Tidal Stream Energy makes use of the tidal flow that occurs between headlands and islands or in and out of estuaries. It is this application that is the focus of much research and development, and new products for this purpose are now being commercialised. These “in-flow” tidal turbines can be arranged singly or in arrays, allowing a range of power outputs to be produced.
For more detailed information please see the REA’s Innovative & Strategic Technologies Forum.
2013 SPR machine operating in Orkney (C) Pelamis