Low-cost direct solar-to-hydrogen ambitions see the light
The road to cheap hydrogen production is riddled with potholes and energy losses. Researchers in Australia have demonstrated rethinking solar technology and skipping electrolysers could hold great promise for reaching the hydrogen holy grail.
Australian National University (ANU) researchers have more than nudged the dial on the efficiency of solar-to-hydrogen production processes which bypass electrolysers and avoid AC/DC power conversion and transmission losses. An ANU-based group say their world record 17.6% efficiency – achieved with perovskite-silicon tandem absorbers – is open to further refinement which could see clean hydrogen production become cost competitive with fuels including brown hydrogen and gas more quickly than expected.
In a paper published in Advanced Energy Materials, lead authors Siva Krishna Karuturi and Heping Shen write that although PV modules have become a commercially viable method for large scale renewable energy generation, "achieving [a] global renewable energy transition further relies on addressing the intermittency of solar electricity through the development of transportable energy storage means."
With funding support from the Australian Renewable Energy Agency (ARENA) and the Australian Research Council (ARC), the ANU team has been exploring the potential of a process that Karuturi likens to photosynthesis – it converts the sun's energy directly into hydrogen in a photoelectrochemical (PEC) cell.
The introduction to the paper – which bears the catchy title Over 17% Efficiency Stand-Alone Solar Water Splitting Enabled by Perovskite-Silicon Tandem Absorbers – explains the PEC cell "comprises a semiconductor photoelectrode immersed in an aqueous electrolyte that absorbs light, generating electron-hole pairs that participate in the hydrogen evolution reaction and oxygen evolution reaction."
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