Powering the transition: the expanding role of batteries in shipping

AS THE maritime sector accelerates its transition towards decarbonisation, batteries are emerging as a critical component of the future energy mix. Once viewed primarily as a niche efficiency measure, they are now recognised as a strategic enabler, reshaping how ships are designed and operated.

This shift is being driven by a convergence of factors. Regulatory pressure is intensifying, the cost of emissions is rising and owners are seeking greater operational flexibility. At the same time, battery technology has matured, with falling costs and improving performance opening a wider range of viable applications. The result is a growing consensus across the industry: batteries are no longer optional, but essential to the next generation of shipping.

Crucially, their role goes beyond reducing emissions. Batteries are prompting a broader rethinking of ship energy systems. Rather than being added as a supplementary component, they are integrated into the overall energy architecture. This requires careful analysis of operational profiles and power demand, ensuring each installation is tailored to the vessel’s needs.

When deployed effectively, batteries deliver value across multiple dimensions. From an operational perspective, they enable engines to run at more stable and efficient loads, supporting more efficient fuel use and reducing maintenance. They also support energy optimisation by allowing vessels to store excess energy or charge during low-load periods, including through shore power where available. At the same time, batteries enhance safety and resilience by providing immediate backup power, helping to avoid blackouts and maintain operational control. These benefits are cumulative, reinforcing overall performance.

Environmental gains and cost savings

The extent to which these advantages can be realised depends heavily on vessel type and operational profile. In shortsea shipping, particularly ferries, batteries are already well established. Predictable routes and regular port calls make it easier to optimise charging cycles and energy use, enabling hybrid or even fully electric operations in certain cases. In cruise shipping, batteries are typically deployed as part of hybrid systems to manage variable power demand and enhance operational flexibility. In both segments, the business case is increasingly compelling, combining environmental gains with cost savings.

For deepsea shipping, the picture is more complex but no less promising. Innovative concepts, on which RINA is also working, highlight how batteries can play a transformative role in vessel design. Rather than acting as the primary propulsion solution, batteries are used to reduce reliance on auxiliary engines and improve overall system efficiency. By shifting energy generation towards the main engine and supporting operations at port, they can reduce fuel consumption and emissions as well as the maintenance cost of the aux engines.

In addition, they provide an important safety buffer, ensuring vessels retain power and manoeuvrability in the event of system interruptions, while offering flexibility for an uncertain future fuel landscape. Also, when the conditions for the selection of the solution that will take shipping to net zero mature, there will be no need to retrofit the aux engines, which represents serious cost savings as well.

The growing momentum behind batteries is closely linked to improvements in technology and economics. Prices have fallen significantly, driven in part by the shift towards lithium iron phosphate chemistries and increased competition from major global manufacturers. Performance has also improved, with longer lifetimes and a wider range of solutions available. As a result, more projects are becoming financially viable, and assumptions about high costs are rapidly becoming outdated.

Safe implementation

However, successful implementation is not without its challenges. The financial case must be carefully evaluated, particularly in relation to payback time and battery lifespan. Integration constraints, such as space and weight, can influence system design, while safety considerations, including fire protection and system redundancy, remain paramount. Addressing these factors requires robust engineering, detailed feasibility studies and a clear understanding of regulatory requirements.

This is where classification societies and technical partners play a vital role. Through design support, approval processes and certification, they help ensure that battery systems are effective, safe and compliant, from initial concept through to delivery and operation.

Looking ahead, the importance of batteries is set to grow further. While their role will vary across vessel types and operating profiles, their importance will continue to grow. In an environment where the future fuel mix remains uncertain, batteries provide flexibility, allowing vessels to adapt to different pathways as they emerge.

For an industry that has long relied on established practices, this represents a significant shift. Batteries, in their various forms and applications, will play a central role in shaping a more efficient, resilient and sustainable maritime future.

William Nyström, Marine Design & Engineering Technology and R&D Operations senior consultant at Foreship by RINA