Resource assessment parameterization impact on wave energy converter power production and mooring loads

•Quantifies wave and environmental impact on wave energy converter power and mooring line tension.•Baseline method overpredicts mean power (11.6%), underestimates maximum (328%).•Baseline method overpredicts mean (182%) and maximum mooring tension (729%).•Wave groups and wind speed identified as key factors in power prediction accuracy.•Wave/current direction and current speed are key factors for mooring tension.