CMA CGM will be making its own contribution to the growing number of battery micro-feeders with a new collaboration in Vietnam, transporting goods for Nike along the Dong Nai river to Cai Mep Port.

The carrier's so-called 'e-barge' will have a capacity of around 100 teu, its renderings indicate, and will carry sportswear from Nike's 31 factories in and around Ho Chi Minh City to the Gemalink terminal at Cai Mep.

The vessel will recharge its batteries using solar power generated at Cai Mep, where buildings already benefit from an abundance of rooftop solar panels - a technology lagging elsewhere in the world - and where a number of further renewable energy projects are planned.

A number of very small electric container vessels and barges have been tested in recent years, the most famous of which is Yara Birkeland, launched in 2019. Last year saw the launch of Cosco N997, a 700teu Yangtze River ship with 50MWh of battery capacity, and this year Ningbo Ocean Shipping ordered two 740 teu feeders each powered by 19MWh of battery packs.

A September report by the Maersk Mc-Kinney Moller Center for Zero Carbon Shipping highlighted that the >1,100 teu size bracket - presently under-utilised and deemed to be uneconomic in many cases - would be the most feasible vessel segment to accommodate battery-electric operation.

A more efficient use of energy means that, although battery space would still take up a proportionately large space on such vessels, perhaps not as much will be needed as thought, with a battery-electric propulsion system roughly doubling what is possible using an engine and fuel tanks.

The adoption of shore power by ports, and the ability of battery-electric systems to make a better use of generated renewable energy than electro-fuels like methanol and ammonia, would make them an attractive and affordable option for short-distance feeder voyages.

"We believe voyage energy requirements up to and around 250 MWh and smaller... represent a relevant field," the study determines.