Hydrogen production in integration with CCUS: A realistic strategy towards net zero

It is believed that hydrogen will play an essential role in energy transition and achieving the net-zero target by 2050. Currently, global hydrogen production mostly relies on processing fossil fuels such as coal and natural gas, commonly referred to as grey hydrogen production while releasing substantial amounts of carbon dioxide (CO2). Developing economically and technologically viable pathways for hydrogen production while eliminating CO2 emissions becomes paramount. In this critical review, we examine the common grey hydrogen production techniques by analyzing their technical characteristics, production efficiency and costs. We further analyze the integration of carbon capture, utilization and storage (CCUS) technology, establishing the zero-carbon strategy transiting from grey to blue hydrogen production with CO2 capture and either utilized or permanently stored. Today, grey hydrogen production exhibits technological diversities, with various commercial maturities. Most methods rely on the effectiveness of catalysts, necessitating a solution to address catalyst fouling and sintering in practice. Although CCUS captures, utilizes or stores CO2 during grey hydrogen production, its wide application faces multiple challenges regarding the technological complexity, cost, and environmental benefits. It is urgent to develop technologically mature, low-cost and low-energy-consumption CCUS technology, implementing extensive, large-scale integrated pilot projects.