When the ocean is considered as a power source there are two ways it can be used to generate power. Mechanical power can be harnessed as a result of the power in ocean swells, currents and tidal movements. Thermal power can be delivered through the differing temperatures of the ocean’s water. Currently there three main area’s that are being used as a resource.
The constant motion and pressure of waves can be harnessed by buoys or floating platforms. This movement is then converted to electricity.
One method of harnessing energy from waves is by using attenuators. They are long multi-segmented structures that move and flex as they float on the surface of the ocean. This movement is then converted to electricity using hydraulic pumps or other converters.
Similar to hydro electricity – a dam is constructed in a tidal estuary or small bay. When the tides moves in or out the water is forced through a turbine that creates electricity.
The Rance Tidal Power Station in France is the world’s first and largest tidal power station. The cost of the electricity produced by Rance Power Station is less than nuclear power generation.
Dams are not always required to harness the power of tidal energy as there are free standing structures which uses the water flowing past to drive a turbine and don’t require the complete blocking of a tidal flow.
Ocean Thermal Energy
Ocean Thermal energy production is reliant on the temperature difference in water on the surface of the ocean compared with water on the bottom of the ocean. The biggest variant in Ocean surface to floor temperatures occurs in the tropics.
Ocean Thermal energy conversion is still considered an emerging technology with the main technical challenge being converting small temperature differences into power. Land based and floating Ocean Thermal experiments are currently under way around the world but Ocean Thermal energy is not currently a viable renewable energy prospect in Australia.
Using the ocean as a resource to produce electricity is a relatively new concept and there are many exciting prototypes under development to achieve this.