Marrying Sails and Biofuel, Odfjell Tanker Demonstrates ‘First’ Near Carbon-Neutral Transatlantic Voyage

by Naida Hakirevic Prevljak (Offshore Energy) Chemical tanker Bow Olympus is currently crossing the Atlantic powered by a combination of wind-assisted propulsion and a certified sustainable 100% biofuel. The milestone voyage proves how existing technologies and fuels can be paired to accelerate deep-sea shipping’s transition to net-zero emissions, Norwegian shipping company Odfjell said.

Real-time data from the voyage confirms that this dual propulsion approach is not only technically feasible but also impactful: The vessel’s greenhouse gas (GHG) emissions on the current voyage meet the 2050 Fuel EU Maritime GHG intensity targets and IMO’s GFI Direct Compliance targets at least until 2044.

The power of wind-assisted propulsion has been tested through Bow Olympus’ first two cross-Atlantic voyages. The four 22-meter suction sails have been operational under varying weather conditions, with the performance closely monitored by Odfjell’s crew and technology team on board and onshore.

To remind, Spanish company bound4blue completed the installation of the four eSAIL suction sails on the vessel in March 2025.

“The results have surpassed our expectations,” Erik Hjortland, Odfjell’s Vice President Technology, commented.

“Even in good, but not perfect, wind conditions, we observed a 15-20% energy-saving effect. That translates to five tons of fuel saved per day, equivalent to a reduction of 15 tons of CO₂ emissions per day. On certain parts of the current voyage, we have seen up to 40% fuel consumption reductions. These are very promising figures. We are thrilled to note that our initial calculations are confirmed and even exceeded.”

Using a new type of AI-based weather routing system allowed the five-year-old 49,000 dwt vessel to take full advantage of the prevailing wind conditions.

“One surprising finding is that even light wind as high as 15 degrees on the bow generates noticeable effect. This means that we can probably operate the sails more often than anticipated, positively affecting the already healthy return of investment figures. The sails also offer stabilizing and roll-damping effects,” Hjortland adds.

“Based on current data, we expect that the sails will continue delivering significant fuel savings on future deep-sea voyages in all basins.”

In addition to the sails, Odfjell decided to double the exploration and added another element to Bow Olympus’ current Atlantic crossing: 100% sustainable biofuel. The goal was to explore a pathway towards near-net-zero operations for a deep-sea vessel. The bunkered biofuel was sourced from certified sustainable waste materials.

As Bow Olympus is expected to reach European shores soon, it has demonstrated that the dual propulsion solution is a realistic pathway to carbon neutrality for deep-sea shipping, 25 years ahead of time: The voyage shows a full 85% reduction in GHG intensity compared to conventional fuels, without technical investments or upgrades required to consume the fuel. In addition, the energy efficiency is improved by 15-20% by the use of sails.

Over the past decade, Odfjell has installed more than 140 energy-saving devices on its vessels, improving carbon intensity by more than 53% compared to the 2008 IMO baseline. Having exhausted most conventional upgrades, Odfjell is now focused on next-generation solutions—such as wind propulsion—to meet its 2030 goal of 57% carbon intensity reduction. To move the needle beyond 57%, a fuel switch is required. The company has chosen to remain flexible, keeping all doors open at a time when the fuel of the future for shipping remains undecided. The choice of biofuel for this proof-of-concept voyage was done to demonstrate one of the pathways.

“We will now drill into the data, assess the lessons learned, and use the experience as a foundation to decide our next steps. There are unknown variables yet to be clarified, such as the impact of varying weather conditions, trade lanes, vessel configurations, etc. Still, I am positive that we have begun charting a credible course toward carbon neutrality,” Hjortland concluded. READ MORE