Concentrated solar thermal (CST) technology harnesses the sun's power to generate electricity.
The advantage of CST technologies is that they provide a dispatchable energy supply – that is, their power output can be adjusted based on grid demand. This makes them more flexible than traditional solar PV plants.
Globally, CST technology is being deployed on a large scale to provide electricity, and storage systems are also being investigated.
Abundant sunshine and plenty of open space means Australia is ideally placed to take advantage of CST technologies for energy generation.
Technology types
There are several types of concentrated solar thermal plants:
- Linear Fresnel – consists of long rows of flat or slightly curved mirrors that move independently on one axis. The mirrors reflect sun to fixed linear receivers mounted above them on towers.
- Tower – involves an array of heliostats (large mirrors with two-axis tracking) that concentrate sunlight onto a fixed receiver at the top of a tower.
- Dish – a highly efficient emerging technology in which a paraboloidal dish with two-axis tracking focuses sunlight to a point receiver.
- Trough – the most widely deployed technology. Uses parabolic mirrors to track the sun from east to west
Concentrated solar thermal in Australia
CST energy generation in Australia is still in its early stages of development. This is primarily due to the relatively high cost of the technology compared to more established forms of renewable energy.
Australia currently has one large-scale solar thermal plant – a 9.3 MW facility that has been added to the Liddell coal-fired power plant in NSW. Covering some 18,490 square meters, the linear Fresnel array is used to pre-heat feedwater for the coal-fired power station.
While CST is not seen as a viable storage option in the short term, it could play an important role in the future as the cost of the technology falls and the penetration of renewables increases.