February 22, 2009 Cloncurry, a town of over 4000 people in north-west Australia, is gearing up to produce solar thermal power capable of supplying all of ts electricity needs, 24-hours a day. The technology used will ensure the 10 megawatt Cloncurry solar thermal power station will continue to generate electricity when the sun is not shining and will deliver about 30 million kilowatt hours of electricity a year. Up to 8000 mirrors will reflect sunlight onto graphite blocks through which water will be pumped to generate steam that will operate a conventional steam turbine electricity generator. Because heat stays in the graphite, the system will work through the night and on overcast days.
Cloncurry, which is the first town in the State of Queensland to go totally solar, is a perfect candidate for solar thermal power generation, having long claimed the title of having recorded Australia's hottest day - 53 degrees Celsius in the shade in 1889.
The design to be implemented by Lloyd Energy Storage is a solar power tower. Solar energy is collected by tacking heliostats (mirrors) totalling 60,000 square feet that focus the sun’s rays on to large 10 ton graphite block mounted at the top of a tower. A total of 54 towers of 18 m (59 ft) high will be constructed. The thermal energy is turned into electricity on demand by passing water through tubes embedded in the graphite to make steam that drives a steam turbine to generate electricity. Less water will be used in the turbine than falls in an average year on the power station's roof. Test sites using a single tower mounted graphite boiler have been constructed in Comma and Newcastle NSW.
Outback solar dish power stations
Solar power is well suited to small, isolated communities where access to the national electricity grid can be difficult or expensive. Solar dish power stations have been installed at three remote indigenous townships in Australia's Northern Territory. Thirty parabolic reflector dishes, each 14 meters (46 feet) in diameter, generate 24 Kw whenever the sun is 5 degrees above the horizon giving each township between 200 and 300kw providing 1.5 gigawatts per year in total.
Another type of solar technology has been proposed for Buronga in western NSW. A solar updraft tower would heat air in a very large circular greenhouse-like structure. The resulting convection causes the air to rise and escape through a tall tower. Moving air drives turbines, which produce electricity.
In Alice Springs, which lies in the country's red center, multiple installations of large solar dishes will track the sun to provide clean energy for the city in a project funded under the Australian Govenrment's Solar Cities scheme. The dishes will be connected to the grid and generate electricity for Alice Springs directly from the sun, offsetting some of the requirement to transport fossil fuels long distances.
The Queensland Government has committed $7 million towards the $30 million Cloncurry power station. This project will determine if this clean energy solution can be replicated in other rural and remote areas of Australia. It is a first for Australia and would generate enough electricity for about 3500 homes. It is expected to be running by early 2010.
Paul Evans
