Ports increasingly are adopting shore power, or “cold ironing,” to reduce emissions from vessels at berth and improve local air quality. However, shore power’s operational deployment often is limited by grid capacity, power quality requirements, and the need for high reliability and power quality. These constraints are particularly relevant for ports with limited electrical infrastructure, where a grid-only approach may not be sufficient to support increasing large and variable shore power demand as port and vessel electrification expands.

How can ports deliver reliable shore power when grid capacity falls far short of demand? To address these grid-constrained conditions, INNIO analysed an integrated port microgrid concept intended to support shore power operations under limited grid capacity. The findings suggest that shore power should be treated not simply as a grid connection project but as an operational energy system requiring flexibility, resilience, and active optimisation.

INNIO’s analysis centered on a representative port scenario in which peak shore power demand reached approximately 20 MW while the available grid connection was limited to 3 MW. To bridge this gap, the proposed architecture combined on-site dispatchable generation, battery energy storage, photovoltaic generation, waste heat recovery, and advanced microgrid controls.

The analysis was based on annual operational simulations designed to reflect the variability of vessel arrivals, departures, berth occupancy, and shore power demand. Particular attention was given to practical operating requirements, including voltage and frequency stability, spinning reserve, redundancy, power quality, black-start capability, and seamless transition between grid-connected and islanded operation.

The results indicated that the microgrid configuration was capable of supporting the modeled shore power demand while maintaining operational continuity within the simulation parameters. Battery storage was shown to support short-duration transients, helping manage ramping events and maintaining uninterrupted service during modeled grid disturbances. In addition to supporting shore power demand, the evaluated microgrid architecture may provide operational capabilities such as fast frequency response and black-start functionality, which can help improve system resilience and recovery during grid disturbances.

INNIO also compared the operational cost of microgrid-supplied shore power with conventional onboard auxiliary engine generation. The analysis indicated a potential for energy cost reductions of approximately 20% in the modeled scenario compared with conventional onboard auxiliary engine generation, while also reducing local emissions from vessels at berth. Actual results may vary based on site-specific operating conditions, energy prices, regulatory requirements, and system configuration.

In addition, the same architecture may support progressive decarbonisation through increased renewable penetration, thermal energy recovery for heating and cooling, and future integration of low-carbon fuels like biogas, bioLNG, or hydrogen.

The findings suggest that integrated microgrids may provide a viable option for supporting cold ironing applications while helping address emissions-reduction objectives and operational requirements for ports facing constrained grids. This approach could support broader port electrification, energy storage deployment, grid modernisation, and system flexibility objectives across energy-intensive infrastructure.

Author's Note: The analysis described in this article is based on engineering simulations of a representative port scenario and is intended to illustrate one potential approach to addressing grid-constrained shore power applications. Actual project outcomes, including operational performance, costs, and emissions reductions, will depend on site-specific conditions, system design, energy prices, regulatory requirements, and other factors.