NREL advances renewable hydrogen production process

Hydrogen

United States – Perovskite materials have the potential to play a key role in a renewable hydrogen production process, according to a study by scientists at the National Renewable Energy Laboratory (NREL).

Hydrogen has emerged as a key carrier for storing energy generated by renewable resources, as well as a replacement for fossil fuels in transportation, ammonia production, and other industrial applications. The ability to meet the Department of Energy’s Hydrogen Energy Earthshot—a recently announced goal to reduce the cost of clean hydrogen by 80% to $1 per kilogram in a decade—is critical to the successful use of hydrogen as a fuel.

New technology

The NREL researchers looked into a new water-splitting technology called solar thermochemical hydrogen (STCH), which has the potential to be more energy efficient than the traditional electrolysis method. To split water into hydrogen and oxygen, electrolysis requires electricity. STCH is based on a two-step chemical process in which metal oxides are heated to over 1,400°C and then re-oxidized with steam at lower temperatures to produce hydrogen.

The paper supports the Department of Energy’s HydroGEN program by looking at system-level design and techno-economic analysis for integrating possible materials into a solar-fuel platform and complementing ongoing materials discovery research. Machine learning, defect calculations, and experimental work were used in the HydroGEN program to develop new perovskite materials. The researchers must find perovskites that can withstand the high temperatures while still meeting performance goals.

Active research

This paper is part of a series of techno-economic studies on hydrogen production pathways, each with its own set of benefits and drawbacks. Commercial electrolysis, for example, is available, and the electricity required can be obtained from photovoltaics (PV). However, the PV cells used only capture a portion of the solar spectrum. The entire spectrum is used by STCH. STCH is able to create the chemical reaction thanks to concentrated solar thermal power.

The scientists noted that active research into the best materials for the STCH process is critical to the success of this method for hydrogen production. The Hydrogen and Fuel Cell Technologies Office of the Department of Energy is funding this study.

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