Dataset for: Degradation-aware tri-objective optimisation of gigawatt-scale PEM green hydrogen production: the hidden cost of ignoring stack degradation

Results data supporting the manuscript submitted to Applied Energy: (1) canonical Pareto-optimal design vectors from the tri-objective NSGA-III optimisation of a gigawatt-scale PEM green hydrogen facility at NEOM, Saudi Arabia; (2) the twenty-run statistical reproducibility campaign; (3) inter-annual resource robustness evaluations across eighteen NSRDB solar years (2005–2022) and twenty-one ERA5 wind years (2004–2024); (4) sequential 25-year degradation rollout trajectories for the four canonical designs. See README.md for full column dictionaries. The simulation model and optimisation code are available from the corresponding author on reasonable request.