Abstract
Offshore expansion of aquaculture is constrained by the prohibitive cost of subsea grid connection, making off-grid renewable generation an alternative to the diesel supply that currently dominates. This study addresses a fundamental question: is there an optimal renewable energy infrastructure suitable for universal deployment in offshore aquaculture, or must solutions be site-specific? A probabilistic decision-making framework incorporating influence diagrams, Markov chains, temporal modelling, investment cost forecasting, and five renewable energy infrastructure designs was evaluated against performance, environmental impact, and techno-economic criteria. Application to two Tasmanian case study sites revealed that multi-source renewable infrastructures outperformed single-source alternatives, yet different technology combinations proved optimal at each location (VAWT-PV-OWC at Bass Strait, HAWT-PV or HAWT at Storm Bay). Under equal criterion weighting, renewable alternatives scored 15–35% lower in utility than diesel generation, at a cost of valued energy approximately 9–14 times the diesel baseline on a 2030 forecast basis, but this ranking reversed once environmental weighting exceeded 37%, within the range of plausible stakeholder priorities. The site-specific rankings were unchanged across all 64 cost-parameter perturbation scenarios tested, indicating robustness to cost-forecast uncertainty. These findings demonstrate that effective renewable energy deployment for offshore aquaculture requires site-specific assessment rather than a one-size-fits-all approach, and provide a transferable methodology for conducting assessment.