Analysis by scientists at the US Department of Energy’s National Renewable Energy Laboratory (NREL) has found that perovskite materials can play an important role in the process to produce hydrogen renewably.
Key to the successful use of hydrogen as a fuel is meeting 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, within a decade.
NREL scientists looked at an emerging water-splitting technology called solar thermochemical hydrogen production (STCH), which can potentially be more energy efficient than hydrogen production by the commonly used electrolysis method.
Electrolysis requires electricity to split water into hydrogen and oxygen. Therefore, STCH is based on a two-step chemical process in which metal oxides are exposed to temperatures above 1,400 degrees Celsius and then reoxidised with steam at lower temperatures to produce hydrogen.
“This is a very complex field, where many questions remain to be solved, especially in terms of materials,” says Zhiwen Ma, chief engineer at NREL and lead author of a new paper entitled System and Technoeconomic Analysis of Solar Thermochemical Hydrogen Production, published in the journal Renewable Energy. His co-authors, all from NREL, are Patrick Davenport and Genevieve Saur.
The article complements ongoing materials discovery research by examining the system-level design and techno-economic analysis for integrating potential materials into a solar fuel platform to support the Department of Energy’s HydroGEN programme. Materials discovery in this programme involved machine learning, defect calculations and experimental work to develop new perovskite materials.
Researchers need to identify perovskites capable of withstanding the required high temperatures and meeting performance targets. This work is part of a portfolio of techno-economic analyses focusing on hydrogen production routes, each with its own advantages and disadvantages.
Electrolysis, for example, is commercially available and the required electricity can be sourced from photovoltaics. However, the photovoltaic cells used only capture part of the solar spectrum. STCH uses the entire spectrum. Concentrated solar thermal energy enables STCH to create a chemical reaction.
This research is funded by the Department of Energy’s Office of Hydrogen and Fuel Cell Technologies.
NREL is the US Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Department of Energy by the Alliance for Sustainable Energy LLC.
Source: NREL (2022)