Study finds that WASPs are key to decarbonization and cutting costs

The ‘Wind First!’ study shows that retrofitting sails on large, existing vessels can save close to half a million US dollars on fuel costs, and reduce fuel consumption and carbon emissions by up to 12%, annually.

This makes wind-assisted propulsion, which is readily available and scalable today, a critical tool to bridge the 2030 target of 5% zero and near zero-emission energy uptake in the IMO GHG Strategy. 

According to the study, adopting wind-assisted propulsion and particularly suction wings, alongside optimised weather routing can significantly reduce greenhouse gas emissions and operational costs. Financial benefits include a lower carbon levy, reduced EU ETS, and improved energy efficiency ratings, leading to even more savings.

The weather routing study examines the benefits of WASPs on the three vessels across three key round-trip routes: Rotterdam – Santos, Accra – Shanghai, and Mombasa – Shanghai, using simulations over a 3-year period (2020-2023) with a departure frequency of one week.

Main results of the study: 

WASP Benefits, Fuel savings and CO2 reduction:

Four suction wings consistently outperform two suction wings in terms of fuel savings, CO2 reduction, and financial benefits across all vessel types and routes.

Route-specific:

The Rotterdam <> Shanghai route is the only one where the EU ETS apply, but only to 50% of the emissions, as it is a route between the EU and a non-EU/EEA country. The route Accra <> Shanghai shows the highest fuel savings for all vessels, particularly for bulk carrier and tanker, both equipped with 4 suction wings. The route Mombasa <> Shanghai shows moderate fuel savings, with containership benefiting the least from WASP.

CII Rating, EU ETS and IMO Carbon Levy:

Vessels with WASP (both 2 and 4 suction wings) generally achieve better CII ratings (A and B) rather than without sails, indicating improved carbon intensity. The IMO carbon levy on GHG emissions from the shipping industry used in this study is 150 USD per 1 tonne of CO2e. The EU ETS applies only to routes calling at EU/EEA ports.

Therefore, Seas AT Risk only analysed the results for the round trip Rotterdam<>Santos, where only 50% of emissions have been considered. The highest EU ETS reduction in absolute terms is for the containership with four suction wings, amounting to 148,995 €. The EU ETS covers routes involving EU/EEA ports, so only the Rotterdam<>Santos round trip (50% of emissions) were considered. The containership with four suction wings achieved the highest EU ETS cost reduction: €148,995.

Installing wind-assisted propulsion to the global shipping fleet is a win-win-win for businesses, the economy and the planet – delivering lower costs for the shipping sector, a smoother energy transition for global trade, and an immediate cut in emissions.

…said Anaïs Rios, Shipping Policy Officer, Seas At Risk.

Conclusions

The results of the statistical study demonstrate the significant potential of integrating wind-assisted propulsion with weather routing and speed optimization strategy to enhance shipping efficiency and reduce environmental impact. In particular, section Weather routing results and analysis describes in detail per route and per vessel the total fuel benefits observed.

• The 80,000 DWT Bulker on the route Accra – Shanghai with 4 suction wings yielded the highest mean relative savings.
• The 125,000 DWT containership, despite its higher baseline fuel consumption and service speed (16 knots), achieved the largest absolute fuel savings (1,301 tonnes) and CO2 reduction (4,051 tonnes) on the Accra – Shanghai route when 4 suction wings were installed, although these savings represented a lower mean percentage gain of 4.76%.
• The 50,000 DWT tanker showed quite good performance as well, especially with 4 suction wings installed, with its highest average savings (8.7%) on the longest route Accra – Shanghai, and 7.14% of mean benefits on the route Rotterdam <> Santos.
• Among the three routes, the Accra – Shanghai route is the most favorable for WASP benefits, while Rotterdam – Santos incurred EU ETS costs, with the containership achieving the highest mean ETS reduction in absolute values (148,995 €).
• The Mombasa – Shanghai route exhibited lower savings, particularly for the containership, attributed to shorter voyage durations limiting weather optimization. Sections CII rating, IMO Carbon Levy, and EU ETS present the economical and regulatory improvements thanks to implementation of WASPs. Financial incentives, including the IMO Carbon Levy (150$/tonne CO2) and EU ETS, further underscored the economic viability of WASPs.
• Studied vessels equipped with 2 and 4 suction wings consistently achieved CII ratings of A and B, reflecting improved carbon intensity. 

In conclusion, WASP integration offers a robust pathway to meet the IMO’s decarbonization targets, particularly when combined with route optimization. Prioritizing a vessel’s configuration with 4 WASPs on long routes maximizes benefits, though vessel-specific factors (e.g., service speed, fuel baseline) must be considered.

The upcoming IMO discussions are pivotal in shipping’s decarbonisation transition and wind must be central to the solution. It is a proven, readily available and cost-effective technology that can help the global fleet meet the IMO’s 2030 energy targets and will only become more valuable as fuel costs are set to quadruple by 2040 with the shift to e-fuels. 

…said Sian Prior, Shipping Policy Director, Seas At Risk, who concluded that scaling up wind-assisted really is a no-brainer.