While solar panels are a familiar sight on Australian rooftops, around 75% of our national energy use still comes from fuel-based sources—particularly in heavy industry and transport.
These sectors are hard to electrify, but CSIRO researchers are working on a new way to power them using sunlight.
CSIRO computer scientist and solar thermal researcher Michael Rae said green hydrogen has the potential to play a key role in Australia’s transition to net zero.
“Most hydrogen today is made from methane, a process that releases emissions, known as grey hydrogen,” Rae said.
“To make green hydrogen, we need methods that can produce it in large volumes, reliably and cost-effectively, without relying on fossil fuels.”
The most common method for producing green hydrogen is electrolysis, which uses electricity to split water into hydrogen and oxygen. But it’s currently energy-intensive and expensive. That’s why CSIRO researchers are exploring simpler, lower-energy alternatives that can work at industrial scale.
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A solar breakthrough in Newcastle
With funding from the Australian Renewable Energy Agency (ARENA), CSIRO has demonstrated a new way to produce green hydrogen using concentrated solar energy and metal particles.
Developed at CSIRO’s Newcastle Energy Centre, the system is called a beam-down solar reactor. Unlike traditional solar thermal systems that focus sunlight onto the top of a tower, this design directs it down onto a platform.
It’s a bit like using a magnifying glass to focus sunlight, but on a much larger scale.
Here’s how it works:
- A field of sun-tracking mirrors or heliostats reflects sunlight onto the top of a central tower.
- The tower redirects sunlight downward into a solar reactor on the platform.
- Inside the reactor, the concentrated heat drives a chemical reaction that splits water into hydrogen and oxygen.
This is the first time beam-down technology has been successfully demonstrated in Australia.
How metal oxide particles unlock green hydrogen
The key to this process is in the solar reactor, a metal oxide called doped ceria—a modified form of ceria (a naturally occurring mineral) designed to improve its ability to absorb and release oxygen at a much lower temperature. This oxygen exchange is what drives the production of hydrogen in the solar reactor:
- When heated by solar energy, doped ceria releases some oxygen atoms.
- When exposed to steam, it absorbs oxygen from water—leaving hydrogen gas which can be captured, stored and used as fuel or for industrial processes.
- The doped ceria is then ready to be reused over and over again.
The doped ceria particles were developed by researchers at Niigata University in Japan. This was the first time they were put to use in a demonstration-scale test.
Professor Tatsuya Kodama from Niigata University said the particles have excellent performance as the catalyst.
“We can produce over three times more hydrogen than what’s typically achieved using standard materials in a similar reaction,” Prof Kodama said.
“That shows real promise for improving the efficiency in future designs.
“We also gained valuable insights into how we can further develop the particles to improve the overall process.”
Why beam-down is a game changer
Traditional solar thermal receivers face downward, limiting how they can be used as reactors. In the beam-down design, the receiver faces upward, offering more flexibility for research and testing—particularly for solid or chemical processes.
CSIRO Solar Technologies leader Dr Noel Duffy said the system opens new possibilities for concentrated solar research and development.
“This is a significant leap forward for Australia’s solar thermal research capability,” Dr Duffy said.
“We can now test high-temperature reactions more easily—not just for hydrogen, but for other applications such as metal refining.”
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Australia’s next step in clean fuel innovation
The project proved the full thermochemical hydrogen production cycle – from solar input to hydrogen output, which has a potential to achieve a solar-to-hydrogen efficiency of higher than 20%. That’s higher than many existing systems, which typically operate around 15%.
CSIRO Principal Research Scientist Dr Jin-Soo Kim, who led the project, said the new design combines performance with simplicity.
“This process uses a two-step water-splitting cycle using a new material that operates at relatively low temperatures for solar thermochemical processes,” Dr Kim said.
“We’re not yet at industrial scale, but we’ve demonstrated strong reactivity under relatively moderate conditions, and with further refinement, it could match electrolysis in both performance and cost.”
Fuelling tomorrow, starting today
With global demand for green hydrogen growing, CSIRO’s beam-down reactor could help Australia become a key player in supplying low-emissions fuel to the world.
Green hydrogen has the potential to decarbonise some of the most challenging sectors— including steelmaking, shipping and iron production, and turn Australia’s abundant sunlight into a powerful force for cutting global emissions.
