Feb 4 (Reuters) - Australia is blessed with abundant sunshine, strong winds and unceasing waves in the south from stormy weather whipped up near Antarctica.
The government is looking to tap these resources and others to generate 20 percent of the nation's electricity by 2020 and has drafted legislation to enshrine this target.
Following are the main types of renewable energy technology under development by companies in Australia.
Australia already generates nearly 1,000 megawatts (MW) from wind and an estimated 4,000 to 5,000 MW of additional wind power capacity is expected to be added over the coming decade, providing there is enough investment in transmission lines.
The vast majority of windfarm sites are in the south along the coasts of southwestern Western Australia, South Australia, Victoria and Tasmania states.
An increasing number of Australian homes are installing small capacity solar panel systems on their roofs. Government subsidies and payments for feeding excess power into the grid will continue to drive investment but the solar industry is calling for the subsidies to be expanded to 5,000 watt systems, instead of 1,500 watts, because that is much closer to the real electricity consumption of most Australian homes.
Australian firm Solar Systems is developing a 154 MW photovoltaic power station in north-east Victoria.
Some firms are developing 24-hour solar power. Lloyd Energy Systems in Sydney is developing solar towers that capture and retain the sun's heat in graphite blocks on top. The sun's energy is directed at the blocks by arrays of mirrors. Water is run through the blocks, generating steam that drives a turbine.
The heat is retained by the blocks at night, allowing the turbines to keep spinning.
Numerous companies are looking to tap large areas of heated rocks about 3 to 5 kilometres below the surface to generate power. Near the centre of the country in particular, there are large areas of high-heat producing granites that contain radioactive elements that produce heat as they decay.
South Australia has been a focus of firms looking to explore and invest in geothermal power, using the heat extracted from rocks between 200 and 300 degrees Celsius (392 to 572 Fahrenheit) to generate power. One of the main companies, Geodynamics Ltd, plans to have a 50 MW power plant operating by 2012, and eventually aims to produce 10,000 MW, or about 10-15 coal-fired power plants.
Carnegie Corp of Western Australia is refining a method of using energy captured from passing waves to generate high-pressure sea water. This is piped onshore to drive a turbine and to create desalinated water.
A series of large buoys is tethered to piston pumps anchored in waters 15 to 50 metres deep (49 to 131 feet). The rise and fall of passing waves drives the pumps, generating water pressures of up to 1,000 pounds per square inch (psi).
The company is looking to have a 50 MW demonstration project finished within the next four years.
A second firm, BioPower Systems, is developing its bioWAVE system that is anchored to the seabed and generates electricity through the movement of buoyant blades as waves pass, in a swaying motion similar to the way sea plants, such as kelp, move.
It expects to complete pilot wave and tidal projects off northern Tasmania this year. (Sources: www.solarsystems.com.au; www.lloydenergy.com/home.htm; here; Australian Geothermal Energy Association Inc www.agea.org.au/; Geoscience Australia here .jsp; www.carnegiecorp.com.au/; www.biopowersystems.com/ (Editing by Clarence Fernandez)