Optimal operation management of distributed and centralized electrolysis-based hydrogen generation and storage systems

•Techno-economic viability of distributed and centralized electrolysis-based hydrogen generation and storage systems (eHGSS) is assessed.•eHGSSs are operated to meet hydrogen demand and participate to the provision of multiple ancillary services to the grid.•Slack variables, penalty terms, and soft constraints are utilized for the management of ancillary services contribution.•Both the distributed and centralized eHGSSs offer maximum financial benefit when operated for multiple ancillary services concurrently.•Participation to the ancillary service market does not significantly increase the grid losses in both systems.