Different technologies adopt different methods for harnessing the ocean's energy. However, the most common oceanic power generation system uses a turbine to drive an electrical generator. It is also possible to use oceanic power generation to desalinate seawater and produce drinking water.
Surface waves and pressure variations below the ocean’s surface can generate intermittent power. Floating buoys, platforms, or submerged devices placed in deep water, generate electricity using the bobbing motion of the ocean’s waves.
Ocean Thermal Energy extracts energy from the temperature difference between the ocean’s warm surface waters and deeper colder layers of the ocean. Thermal energy conversion plants use the water to make steam and then pass the steam through a turbine generator to make electricity. Currently there are no plans to utilise this technology in Australia.
Greenhouse gas savings
Ocean power is a zero-emission electricity source. One megawatt hour of hydro-derived electricity avoids approximately one tonne of CO2.
With its vast coastline, Australia’s near shore wave energy resources could create around four times the nation’s current national power needs. The Southern Ocean, in particular, is one of the world’s largest and most consistent wave energy resources. Regions such as Port MacDonnell in South Australia, Portland, Warrnambool and Phillip Island in Victoria, Albany and Geraldton in Western Australia and parts of the Tasmanian and NSW coastlines are optimal sites for wave energy plants.
The resource is so far almost completely undeveloped, but that is beginning to
change. Currently there are two wave powered generation plants operating in Australia. Oceanlinx Limited at Port Kembla in NSW has a 0.5 megawatt plant and Carnegie Wave Energy has a 0.1 megawatt plant in Fremantle in WA. AquaGen Technologies have a small development wave energy prototype running on Lorne pier in Victoria. Atlantis Resources operates a 0.15 megawatt plant at San Remo in Victoria that utilises the tide. Another 1000 megawatts of ocean power is being evaluated around Australia.
The USA, South America, Western Europe, South Africa, Australia and New Zealand are rated as having some of the best wave energy sites around the world. Given the majority of the Australian population live near the coastline, oceanic power provides a realistic solution to reducing the high costs of distribution and grid connection that other power sources face.
The intensity of ocean currents, tides and waves is able to be accurately forecast, making it easy for the energy market to balance supply and demand and thus provide a reliable energy source.
Internationally, ocean power is still a relatively new technology and most projects are at the prototype or testing phase. The total current world capacity for tidal power is estimated at 300 megawatts. France has led the world with its project at the Rance River operating since 1966, currently delivering 600 gigawatt hours annually.
The future success of ocean power in Australia is dependent upon government policies to support the development and deployment of these emerging technologies. The sector requires a comprehensive policy framework for emerging technologies to take them from research to full scale demonstration.
Renewable energy funding initiatives as well as the national Renewable Energy Target (RET) which aims to ensure that 20 per cent of Australia's electricity supply comes from renewable energy sources by 2020 are important to drive research and development into ocean power technologies.
Marine Energy Sector Industry Report 2010
The marine environment is a vast, largely untapped renewable energy resource. This report has been prepared for the Clean Energy Council to present a snapshot of the Australian Marine Renewable Energy Sector in 2010.
The benefits of harnessing the ocean's energy - fact sheet
The development of renewable energy technology is critical to Australia's clean energy future. Marine energy is currently under-utilised in Australia, despite the potential for marine energy to provide for at least 35 per cent of our baseload power needs.