How Integrated Microgrids Can Redefine Cold Ironing
Ports worldwide are moving quickly to lower emissions and prepare for a more electrified future. A major driver of this shift is cold ironing (or onshore power supply, OPS) – the practice of providing shore-side electricity to docked vessels so they can switch off their onboard auxiliary engines which normally run on maritime fuels. Yet as regulatory timelines accelerate, ports face a growing gap between rising power needs and local grid capacity.
INNIO’s Jenbacher recently examined this scenario, presenting a practical pathway for ports to support cold ironing while navigating high power demand, rising regulatory requirements, and infrastructure constraints. Jenbacher’s analysis focuses on an integrated, modular microgrid concept that combines hydrogen-ready cogeneration, solar photovoltaic (PV) systems, and battery storage to supply cold ironing loads.
The limitations of grid-only approaches
Although conventional shore-power systems reduce emissions, they face structural constraints that make relying solely on the grid challenging. Most ports require substantial grid reinforcement – often 5 to 30 MW per berth* – with long implementation timelines and high associated costs. Many port grids cannot reliably meet strict vessel power-quality requirements without stabilization equipment, and port areas often experience above-average power interruptions, creating operational risks.
Integrated microgrids as a local energy source
Our answer: locally deployed microgrids. By integrating generation, storage, and advanced control systems, microgrids provide a flexible pathway to meet near-term operational needs while complementing grid infrastructure.
In addition, integrating cogeneration into a port-level microgrid creates a more flexible and resilient local energy system. The microgrid incorporates distributed energy resources – including cogeneration units, renewable generation, and energy storage – supported by advanced control, protection, and energy-management systems.
This architecture transitions between grid-connected and islanded operation, fast frequency regulation during vessel connection or disconnection, and voltage stability across wide load variations. The microgrid also supports reactive-power management, improved economic dispatch through its energy management system, and black start capability. The coordinated system helps ports manage vessel load changes, maintain stable operation during shore-power connections, and deliver reliable service even under wide variations in demand.
Insights from Jenbacher’s simulation
Jenbacher team conducted a simulation to develop a more optimized solution for a representative scenario where a port was limited to 3 MW of grid capacity but required 20 MW for cold ironing. The modeled microgrid incorporated on-site cogeneration, photovoltaic (PV) arrays, and battery storage. PV generation provided supplementary power, and the battery storage system supported short-term load fluctuations and black start capability. Heat recovered from the Jenbacher units supplied thermal demand within the port, further reducing total energy costs.
According to the optimization results, the integrated microgrid achieved:
- A 22% reduction in levelized cost of energy (LCOE) compared to traditional onboard power generation from maritime fuel combustion and an additional 20% cost benefit through thermal integration.
- A decrease in annual CO2 emissions of about 36%.
These results highlight how multi-technology systems, anchored by Jenbacher cogeneration technology, can support energy supply and environmental goals without relying solely on external grid upgrades
A phased transition
A phased decarbonization pathway could begin with natural-gas cogeneration equipped with heat recovery, providing an initial (up to) 40% reduction in greenhouse gas emissions. Incorporating solar PV and battery storage raises total reductions to 60–65%. Subsequent hydrogen blending with natural gas can achieve 67–72% reductions, while full hydrogen operation (supported by expanded H2 production and storage) can deliver over 95% emissions reduction.
This phased approach allows a microgrid to evolve from natural gas to hydrogen as fuel availability and infrastructure develop. Combined with renewables and storage, it supports low-carbon cold ironing while maintaining reliable on-site capacity, helping ports meet near-term regulations and long-term climate goals.
Looking ahead
As regulatory timelines shorten and grid capacity challenges persist, local microgrids provide a practical pathway for ports to expand shore power. Even with constraints on grid capacity and renewable deployment, the analysis shows that advanced microgrids, renewable generation, and cogeneration systems can immediately deliver substantial emission reductions and economic benefits when deployed strategically.
* Okti Setyaningsih et al., 2024
