The challenge
Focusing sunlight to generate heat, and more...
Concentrated solar thermal (CST) technology concentrates sunlight onto a target to create very high temperatures. This heat can be used directly in industrial processes or to generate electricity by heating water for steam to turn a turbine.
Harnessing renewable energy to decarbonise Australia's industry is one of our biggest challenges. As lowering emissions becomes essential for industry and the community, we are looking at new ways of generating thermal energy from sunlight. Our challenge is how to make this solar a reliable, stable part of Australia's energy future.
Heliostats are sun-tracking mirrors that concentrate sunlight by focusing it onto a target, generating temperatures of hundreds of degrees. In a heliostat field, a central receiver system or 'power tower' is used to harness the heat of the sun.
Rather than letting it radiate onto the ground, each heliostat magnifies solar radiation by focussing the reflected energy into a small focal point on the tower. A large number of focused heliostats produces a tremendous amount of heat.
Our response
Creating advanced solar thermal systems
Although many commercial CST power stations are already in operation overseas, research is needed to lower the cost of CST technology. We aim to make electricity from CST competitive with fossil fuel-generated electricity in Australia through the Australian Solar Thermal Research Institute (ASTRI).
Our Energy Centre in Newcastle contains the only high-temperature solar thermal research facility of its type in Australia, home to the largest high-concentration solar array in the Southern Hemisphere.
The site has two facilities: Solar Field 1 and Solar Field 2. Both are operated from an elevated control room housing the centre's communications and control systems. Each field contains a tower and a heliostat array that tracks the sun throughout the day, concentrating the solar heat to produce temperatures over 1,000 degrees Celsius (ºC).
Our CST demonstration and research facilities have been used to:
- 'supercharge' natural gas (SolarGas)
- store energy, so that solar power can be used when it's cloudy or after dark
- generate electricity from the sun and air in a solar air turbine at 800 ºC
- combine solar power with state-of-the-art turbines to create steam up to 590 ºC
- run the highly efficient supercritical carbon dioxide Brayton cycle up to 700 ºC.
Pilot-scale research facilities
Recently, through ASTRI and the Australian Renewable Energy Agency (ARENA), CSIRO has been developing three high-temperature pilot-scale research facilities on the solar towers.
Tower 2 already has the Falling Particle Technologies installation, which is a system that uses solid media as the heat transfer fluid and thermal storage media. This system stores solar energy as heat up to 800 ºC. We are also building a high-temperature Integration Test Facility at Tower 2 using liquid sodium metal as the heat transfer fluid for temperatures up to 740 ºC.
On Tower 1, we are developing an ARENA-funded beam down reflector system for a pilot-scale 250kW thermochemical hydrogen reactor in collaboration with Niigata University, Japan. Initially, this facility will be used to generate hydrogen via the redox process, using ceria powder at temperatures of 1,100 to 1,400 ºC. This is a potential solar fuel pathway to generate hydrogen to export to Japan, competitive with hydrogen generation via electrolysis.
Industry decarbonisation
Our Falling Particle Receiver (FPR) technology leverages solar energy to produce high-quality industrial steam, which can be hybridised to generate both electricity and heat. This innovative solution is particularly valuable for hard-to-abate industries such as resource and minerals refining. The FPR system uses monodispersed ceramic particles that are heated by concentrated solar radiation. These particles can reach temperatures up to 1200°C, making them ideal for generating supercritical steam. This steam can then be used in industrial processes or to drive turbines for electricity production. In addition to its high-temperature capabilities, the FPR system is designed to be hybridised with other energy sources, providing a flexible and efficient solution for industrial applications.
By integrating thermal storage, the system can deliver consistent and reliable energy, even when solar radiation is not available. Our research and development efforts have demonstrated the potential of the FPR technology to significantly reduce greenhouse gas emissions in heavy industries. By transitioning to this advanced solar thermal technology, industries can achieve greater efficiency and lower operational costs, contributing to a more sustainable future.