The shipping industry is revisiting wind propulsion technologies, from giant kites to towering sails, to reduce fuel consumption and meet environmental regulations. In 2018, Maersk, then the world's largest container shipping group, installed two 30-meter-high rotor sails on its tanker, the Maersk Pelican, aiming to cut fuel reliance. Cargill's Ocean Transportation division also anticipates its first retrofitted wind-powered vessel by spring, with president Jan Dieleman noting wind's role in minimizing expenses on green propulsion.
Advocates for wind power hope stricter environmental regulations will drive investment. The IMO's Carbon Intensity Indicator (CII) regulations are pressuring shipowners to cut emissions, with Erik Grundt of Rystad Energy predicting an "explosion in rotor sail adoption." Grundt highlights wind as "free" and sails as "proven technologies," contrasting them with costly and potentially toxic clean fuels like hydrogen and ammonia.
However, investment is hampered by uncertainty regarding the actual fuel and energy savings on large vessels carrying over 100,000 tonnes of cargo. Maersk's own analysis found the Pelican's rotor sails resulted in only an 8% reduction in fuel consumption, leading them to sell the vessel in 2021. Tristan Smith, a shipping researcher at UCL, points out that an 8% reduction is insufficient for the targeted 50% overall emission cut, especially considering inconsistent wind conditions.
Other challenges include the cost of installing wind propulsion systems, which Cargill's Dieleman notes is a deterrent, with payback periods potentially extending to seven years. He suggests a widespread adoption of wind ships won't be seen before 2026 or 2027 due to lead times in the industry. Environmentalists also criticize IMO regulations, including the CII, as too weak, citing loopholes that could allow companies to appear more carbon-efficient without making substantial changes, with only Maersk among 16 major shipping groups committing to full decarbonization.
Despite these hurdles, Maersk Tankers has recently scaled up its use of wind-assisted propulsion by installing eSAIL suction sails on its MR tankers, the Maersk Trieste and Maersk Tahiti. This initiative involves a total of 20 eSAIL units across five vessels, manufactured by bound4blue. These 24-meter 'plug and play' suction sails are designed to generate significant lift by drawing air across an optimized surface, potentially delivering double-digit percentage reductions in fuel consumption and CO2 emissions, and improving CII ratings. This move signifies a shift from pilot projects to repeatable rollouts, with a two-step installation process designed to minimize vessel downtime, signaling growing industry confidence in wind propulsion as a mainstream decarbonization strategy.
