Integrated Multi-Energy Microgrids for Port Decarbonization: A Techno-Economic Assessment of CHP-Based Cold Ironing Under Grid Constraints

The decarbonization of port operations is becoming increasingly important due to tightening environmental regulations and the growing adoption of shore power solutions. However, the large-scale deployment of conventional onshore power supply (OPS) systems often is constrained by limited grid capacity, high infrastructure costs, and variability in the environmental performance of grid electricity. Against this backdrop, this study investigates whether an integrated port microgrid can provide a viable alternative for enabling cold ironing in grid-constrained ports. A case study is developed for a commercial port characterized by a maximum grid import capacity of 3 MW and a peak shore power demand of approximately 20 MW. Two alternative configurations are evaluated: conventional onboard auxiliary engine generation and an integrated microgrid incorporating combined heat and power (CHP) units, photovoltaic generation, battery energy storage, and thermal integration through heat recovery. Results indicate that the integrated microgrid can satisfy the required shore power demand while significantly reducing both costs and emissions compared with onboard generation under the assumptions of the case study. The proposed configuration achieves a levelized cost of energy (LCOE) of 0.157 €/kWh, corresponding to a reduction of approximately 22% compared to the conventional onboard auxiliary engine generation, and a reduction in annual CO2 emissions of about 36%. The system also maintains operational continuity during a simulated 24 h grid outage at the hourly simulation resolution, while an N + 1 criterion is adopted separately for sizing the on-site generation architecture. Beyond the quantitative benefits, the findings highlight the role of cogeneration as an enabling technology for integrating multiple energy vectors within port infrastructures. By coupling electricity generation, thermal recovery, renewable energy, and storage within a coordinated microgrid architecture, the proposed solution transforms grid-capacity limitations into opportunities for energy system optimization. The study contributes to the growing literature on ports as multi-energy hubs and provides evidence that integrated CHP-based microgrids can represent a technically feasible and economically competitive pathway for supporting cold ironing in ports where grid reinforcement is constrained, delayed, or costly under the conditions examined in this study.