Maersk has signed a deal to install the first wind sail on a container ship as the maritime industry returns to an age-old technology to cut fuel consumption and comply with tougher environmental regulations. The sail, a 35m-high rotor sail designed by the British company Anemoi, will be retrofitted to a medium-sized container ship as a pilot project to demonstrate whether the technology can meaningfully cut the cost of fuel and emissions permits. Nick Contopoulos, chief commercial officer at Anemoi, said that container ships presented a particular challenge for installing wind power as nearly all the deck space was used for cargo storage.

But he added that there were benefits to using modern sails on container ships. "They are on very dedicated routes so knowing the predictability of wind [and] the vessel's operating speed, you can target the high wind profile routes which improves the business case and the return on investment," he said. The rotor technology spins in the wind using a physical phenomenon by which spinning objects create propulsion, known as the 'Magnus effect', to push the vessel forward.

Ole Graa Jakobsen, head of fleet technology at Maersk, said that the world's second-largest container shipping line saw the project "as a valuable opportunity to build practical experience and assess its relevance for our fleet and for container shipping more broadly". Gavin Allwright, secretary-general of the International Windship Association, said that there had been a steady increase in interest in wind propulsion technologies as environmental regulations for shipping tighten.

The EU has included the maritime sector in its emissions trading system since 2024 and has introduced new rules requiring shipowners to cut the emissions intensity of the fuels they burn. Shipping currently accounts for around 3 per cent of global annual carbon emissions.