The CSIRO has demonstrated a new way to produce green hydrogen at its Newcastle Energy Centre, using concentrated solar energy and a novel ‘beam-down’ reactor powered by metal particles. The approach could help replace fossil fuels in energy-intensive industries such as steel and aluminium production – sectors that are difficult to electrify and still heavily reliant on coal or gas.
The solar hydrogen system works by concentrating sunlight onto a central tower, where mirrors called heliostats follow the sun throughout the day. Instead of directing that energy upwards like in traditional designs, CSIRO’s system reflects the light back down into a receiver at ground level, known as a beam-down reactor.
The concentrated heat inside the reactor drives a thermochemical process that splits water into hydrogen and oxygen. Rather than using electricity – as with electrolysis – the process relies on a heat-activated metal oxide material known as doped ceria.
Doped ceria, developed by researchers at Niigata University in Japan, is a modified mineral designed to release and absorb oxygen more easily at lower temperatures. When heated, the particles release oxygen atoms. When steam is added, the material takes back oxygen from the water vapour, leaving behind pure hydrogen gas. The doped ceria can then be reused repeatedly in this cycle.
Professor Tatsuya Kodama from Niigata University explains: “We can produce over three times more hydrogen than what’s typically achieved using standard materials in a similar reaction.”
This is the first time beam-down technology has been used successfully in Australia to produce hydrogen. The design allows the solar receiver to face upwards, which offers greater flexibility for testing a range of high-temperature chemical reactions. This includes processes beyond hydrogen, such as metal refining, that could benefit from concentrated solar heat.
Dr Noel Duffy, CSIRO Solar Technologies leader, is enthusiastic about the new technology.
“We can now test high-temperature reactions more easily – not just for hydrogen, but for other applications such as metal refining,” Duffy said.
“This is a significant leap forward for Australia’s solar thermal research capability.”
Compared to electrolysis, which depends on electricity and can be costly to scale, this new system avoids the need for power input entirely. The process has already demonstrated a solar-to-hydrogen efficiency higher than 20 per cent, which is above the level achieved by many current hydrogen technologies.
The research was supported by the Australian Renewable Energy Agency (ARENA). According to CSIRO Principal Research Scientist Dr Jin-Soo Kim, the team has proven the full hydrogen production cycle – from sunlight to fuel output – using a simple two-step method that works at relatively moderate temperatures. While not yet ready for commercial rollout, the findings suggest the technology could eventually compete with electrolysis on both cost and performance.
