Electrochemical hydrogen production: sustainable hydrogen economy

The development of sustainable energy technologies has received considerable attention to meet increasing global energy demands and to realise organisational goals (e.g., United Nations, the Paris Agreement) of carbon neutrality. Hydrogen is a promising alternative energy source to replace fossil fuels and mitigate corresponding environmental issues. An aspiring method to produce hydrogen is to direct energy from intermittent renewable energy sources for water electrolysis. However, a major obstacle to practically achieving hydrogen storage is the future investment costs of water electrolysis due to the energy-intensive nature of the reaction. In this study, we present an overview of current research interests that produce hydrogen, including different types of water electrolysis such as high-temperature, low-temperature, nuclear-driven, solar-powered, wind-powered, and grid-connected water electrolysis. Electrolysis using organic fuels and hydrogen production as a by-product of various electrolytic methods are also briefly discussed. At the end, we demonstrate the economics, sustainability, and challenges of sustainable hydrogen production reporting since 2005 onwards.