Technology
What is it?
Concentrated sunlight is used to heat up transition metal oxides (e.g. cerium oxide), releasing oxygen. The metal oxides are then reacted with water, which splits to re-oxidise the metal oxide as well as produce hydrogen – the cycle then repeats.
Why is it important?
This process produces hydrogen using only water and sunlight and has the potential to be low-cost due to system simplicity.
Characteristics
- Inputs: Water and sunlight
- By-products: Oxygen
- Operating temperature: ~900 to 1,500°C
- Energy efficiency: Theoretical greater than 30%. Demonstrated approximately 5%
Benefits
- Less complex and fewer steps than hybrid thermochemical water splitting
- Does not require an electrolysis step (therefore no electricity input)
- Zero CO2 emissions
- Make use of concentrated sunlight as heat source
Limitations
- Requires very high operating temperatures
- Dependent on solar irradiation
RD&D priorities
- Improve concentrated solar thermal technologies
- Improve thermal efficiency
- Improve long-term stability of reactor materials
- Conduct fundamental material investigations (e.g. understand mechanism of material melting and sticking)
- Develop overall large-scale system concepts
Known active organisations
- The Australian National University
- CSIRO
- Flinders University
- The University of Adelaide
- The University of New South Wales