Classification and technical target of water electrolysis for hydrogen production

Continuous efforts are underway to reduce carbon emissions worldwide in response to global climate change. Water electrolysis technology, in conjunction with renewable energy, is considered the most feasible hydrogen production technology based on the viable possibility of large-scale hydrogen production and the zero-carbon-emission nature of the process. However, for hydrogen produced via water electrolysis systems to be utilized in various fields in practice, the unit cost of hydrogen production must be reduced to $1/kg H2. To achieve this unit cost, technical targets for water electrolysis have been suggested regarding components in the system. In this paper, the types of water electrolysis systems and the limitations of water electrolysis system components are explained. We suggest guideline with recent trend for achieving this technical target and insights for the potential utilization of water electrolysis technology.