SunHydrogen exceeds 10% solar-to-hydrogen efficiency in lab tests

In preliminary tests at Sparc Hydrogen’s laboratories, SunHydrogen says its 100 cm² module exceeded 10% solar-to-hydrogen efficiency. The result follows testing at Honda’s R&D facilities, where the devices reached 10.8% active-area efficiency.

The module does not work like a standard solar panel feeding electricity into a separate electrolyzer. SunHydrogen combines the light-absorbing semiconductor, its electrical contacts and the catalysts that produce hydrogen and oxygen in one device. When sunlight hits the semiconductor, it creates electrons and holes; the contacts send them to the corresponding catalysts, where they drive water splitting.

That direct coupling is the technical bet. A conventional photovoltaic system needs a separate electrolyzer stack and power-conversion equipment, while SunHydrogen’s architecture matches the semiconductor’s electrical behavior to the electrochemical reaction. The company says this can remove much of that equipment, although a working system still needs electrolyte circulation, gas handling, monitoring, controls and safety components.

The next test is being built around Australia-based Sparc Hydrogen, which is developing a process using concentrated sunlight, water and a photocatalyst without an electrolyzer. Under a planned 24-month collaboration, laboratory work is expected to progress toward on-sun testing at Sparc Hydrogen’s Sharp facility in South Australia, subject to technical milestones. The companies will also assess hydrogen cost and whether the work could lead to module supply or a manufacturing licence.

So what changes in practice? If the architecture can retain its efficiency as it grows, it could put the light-capture and hydrogen-making steps in one manufacturable panel, reducing the amount of electrical equipment around a hydrogen system. That remains a development path, not a deployed product: SunHydrogen reports efficiencies approaching 9% outdoors with a larger 1.92 m² module, while a possible next phase with Honda R&D would target efficiencies approaching 15% on larger modules. The figures come from company testing, and the source reports no independent assessment yet.