Advancement of fuel cells and electrolyzers technologies and their applications to renewable-rich power grids

As renewables are being integrated into the power grids, new challenges are introduced, such as the impacts on the grid due to sudden variations in weather conditions and load demands. Green hydrogen energy (GHE) storage, using electrolyzers (EL) and fuel cells (FC), has been identified as one of the potential solutions. As the world transitions to a zero-carbon economy, the production and storage of hydrogen using EL from surplus renewable is receiving global interest. Whenever electricity is required, the stored hydrogen gas can be used to produce electrical energy using an FC to supply to the loads/grid. To make the renewable energy sources (RESs) and FC/EL integrated power systems optimal, efficient, reliable, and cost-effective, an adaptive energy conver-sion system and power management control strategy (PMCS) that includes advanced control algorithms need to be formulated to utilize the surplus of renewable energy.Despite many review studies on FCs/ELs integrated power systems, a detailed review of FCs/ELs technologies for utilizing the renewable energy surplus is still limited in terms of different types of grids (AC or DC) integrated topologies, multiple types of FCs/ELs models, and a variety of power electronic interfaces with appropriate PMCS. This paper presents a comprehensive review with a more specific assessment of FC/EL comprised GHE storage technologies for the widespread interconnection of RESs. It is expected that this in-depth review will help in advancing the relevant technologies and eventually support the transition to a zero-carbon economy and meet Goal 7 of the United Nation Sustainable Development.