GCMD study reports 7.2% mean power savings from wind propulsion on EPS tanker

The Global Centre for Maritime Decarbonisation (GCMD) on Friday (5 December) said it implemented a Wind Assisted Propulsion Systems (WAPS) performance monitoring method with Singapore-based Eastern Pacific Shipping Pte Ltd (EPS) to measure suction sails’ performance on tanker Pacific Sentinel.

GCMD said WAPS are gaining traction as an important decarbonisation lever, but uptake is still far below what is needed to meet regulatory targets.

A major barrier is its inherently variable fuel savings, which depend on operational and environmental factors such as routing and weather conditions. This is compounded by the lack of a standardised method to accurately quantify WAPS performance during real-world operations.

To address this, GCMD and EPS implemented the study and published their joint report titled Quantifying energy savings from wind-assisted propulsion systems (WAPS): A case study on the Pacific Sentinel.

The Pacific Sentinel sampled predominantly near-headwind conditions during this four-month testing period. Accordingly, the mean instantaneous power savings derived from valid on-off tests during this period was 7.2%, with a 95% confidence interval between 6.2% and 8.2%. If the vessel experienced more favourable wind conditions, the savings could be higher.

Instantaneous savings reached as high as 28.1% when the apparent wind angle was 47° and wind speed was 15.3 m/s. There were instances where near-headwind conditions resulted in negative power savings as low as -14.0%. Both are statistically rare events given the range of wind conditions experienced in this particular testing period, at three standard deviations from the mean of instantaneous power savings derived during this testing period.

Over four months of testing, they observed a range of power savings across different wind conditions:

• Mean instantaneous power savings: 7.2% (95% confidence interval of 6.2–8.2%)
• We also observed peak savings of up to 28.1% and negative savings of –14.0%, though both were statistically rare.

GCMD said the findings matter as the analysis captures the full distribution of observed power savings linked to wind conditions rather than relying on a single aggregated value.

“This provides a more realistic and confidence-based understanding of suction sail performance on the Pacific Sentinel,” it added. 

GCMD added that the pilot shows how much, and under what conditions, WAPS deliver savings. As GCMD runs more pilots, larger datasets will enable modelling and fuel savings predictions across diverse operating conditions. 

“With quantified and verifiable savings, a pay-as-you-save repayment mechanism becomes viable, linking repayments directly to measured performance,” it added.

“This underpins our recently launched Fund for Energy Efficiency Technologies (FEET) fund, which decouples retrofit financing from vessel mortgages by offering unsecured leases.”

Note: The report can be accessed here. 

Related: GCMD: Vessel retrofit fund using pay-as-you-save repayment mechanism closes at USD 35 mil
Related: Singapore-based EPS extends eSAIL installation with bound4blue on newbuild tanker

Photo credit: bound4blue
Published: 8 December, 2025