Electric propulsion: powering the decarbonisation of close-to-shore shipping

Close-to-shore shipping is the cornerstone of global trade. Domestic and coastal voyages account for 9.2% of global shipping emissions, with the entire marine industry responsible for about 3% of global CO2 output. As international and regional regulations tighten, through measures such as IMO’s Net-Zero Framework, operators face rising operational costs and mounting pressure to decarbonise. Innovations in electric propulsion are set to play a key role in improving operational efficiency and reliability, resulting in reducing marine emissions; by integrating new solutions, operators can significantly lower fuel consumption and future-proof their fleets.

The case for electrification

Electrification for close-to-shore maritime operations is no longer a distant goal. Near-shore and predictable operations offer ideal conditions for deploying electric propulsion systems without compromising on performance or range. Segments such as short-route ferries, harbour craft, and inland waterway vessels represent significant potential for transition, and compact systems are ideal for these vessels where stop-and-go operations are common. Solutions, which include marine motors, inverters, and batteries, may be hybrid or fully electric and can be integrated into existing vessels or newbuilds.

“The low-noise, low-vibration of the electric drivetrains make these solutions especially effective for domestic operations”

Fully electric systems rely solely on a battery energy storage system to power the vessel for the entire route, and this is well suited to short-distance shipping. Then, the low-noise, low-vibration of the electric drivetrains make these solutions especially effective for domestic operations, including on rivers, lakes, and ferry routes. When incorporated into newbuilds, electric propulsion systems require lower space requirements and maintenance costs and benefit from increased manoeuvrability. Estimates of the conversion efficiency from input energy to propulsive power range to as high as 90% and 98%. 

ABB has delivered a fully integrated electric propulsion system for the first all-electric ‘Maid of the Mist’ tour ferries, allowing passengers to experience Niagara Falls completely free of engine noise, fumes, and emissions. These zero-emission ferries demonstrate the benefits of fully electric propulsion for small and mid-sized passenger vessels, enabling sustainable operation with maximum reliability.

Adapting fleets with hybrid and retrofit solutions

Hybrid and retrofit solutions are becoming essential as diverse vessel types, from ferries to harbour tugs and coastal supply ships, each require purpose-built approaches to meet operational and environmental demands. The main benefit of hybrid systems is their ease of adaptation to new fuels, as upgrading requires replacing only the generators rather than the entire propulsion system.

Modular system designs now allow seamless integration with existing propulsion setups, enabling smooth transitions that preserve power performance and optimise onboard space across a wide range of configurations. By adopting retrofit solutions, operators can reduce downtime, extend vessel lifespans, and achieve reliable, lower-emission operations without compromising service continuity. 

To this end, ABB will supply the propulsion systems to Scotland’s Caledonian Maritime Assets Ltd for seven all-electric ferries between late 2027 and early 2029. The 50-m ferries will serve nine routes in the Clyde and Hebrides region on Scotland’s west coast. Integrated with the AXME Marine Motor, and with wall-mounted HES880 Mobile Inverters, the comprehensive solution combines high power density and light weight in a small footprint.