Towards zero-carbon power supply: development of a multi-energy coupled offshore green energy production island

Offshore islands, with their abundant renewable energy resources and geographic advantages, present significant potential for the development of low-carbon, multi-energy systems. This study develops an innovative framework for the configuration optimization and operational analysis of multi-energy coupled offshore green energy production islands, aiming to achieve zero-carbon energy supply. A multi-objective model is developed to optimize system configuration, incorporating techno-economic analysis and environmental performance and efficiency evaluation. Key performance metrics including levelized cost of energy (LCOE), energy storage efficiency and curtailment ratio, are employed to evaluate system forms and configurations. The proposed optimized system integrates renewable energy sources including photovoltaic (PV) and wind power, with hydrogen production, ammonia storage and methanol synthesis as multi-scale energy storage and transfer pathways. The system fosters collaborative operation between offshore islands and mainland energy networks, enhancing energy efficiency and flexibility. Case studies demonstrate that coupling renewable energy with green fuel production provides a sustainable pathway for offshore islands to achieve zero-carbon energy supply with a LCOE of 0.128 USD/kWh, a load satisfaction rate exceeding 99.8% and a curtailment ratio below 6%. This research offers valuable insights into the design and operation of zero-carbon island energy systems, advancing the transition to a sustainable, low-carbon energy future.