AMF #8 - Wind Assisted Propulsion’s Role in Shipping’s Decarbonization Journey

1. Introduction

The maritime industry faces a significant challenge in its journey toward decarbonization. Within this crucial discussion about the future of shipping, a prominent energy-saving innovation has emerged, wind assisted propulsion systems.

Wind-assisted propulsion stands as a practical, short-term solution for reducing emissions, aligning with the Initial IMO GHG Strategy and regulatory frameworks like the EU ETS. Furthermore, these technologies promise even more substantial savings when incorporated into newly optimized ship designs in the medium to long term.

The application of wind propulsion technology delivers both technical and commercial viability in the near term, offering fuel savings of 5% to 9%. As this technology evolves and is integrated into newly optimized ships, the potential for fuel savings could reach an impressive 25%.

Wind solutions are not only cost-effective but also require no alterations to port infrastructure. They grant ship owners enhanced operational autonomy in risk mitigation. Consequently, the adoption of wind solutions can play a critical role in reducing emissions in the short term, decreasing the carbon intensity of the global fleet, and aiding in the pursuit of near-term IMO GHG reduction targets.

2. Impact on Emission Reduction Efforts

In 2019, during the thirty-first IMO Assembly, a resounding statement echoed, shedding light on the vital role of wind propulsion technologies. This call reverberated among IMO delegates, emphasizing the need to evaluate these promising innovations alongside other propulsion systems and alternative fuels to fulfill the ambitious objectives outlined in the IMO GHG Strategy.

In line with the IMO Strategy, a near-term GHG reduction approach combines mandatory technical and operational criteria. This approach seeks to diminish the carbon intensity of international shipping through an energy-efficient framework involving the Energy Efficiency Existing Ship Index (EEXI) for all vessels, coupled with the EEDI for new ships. The implementation of the Carbon Intensity Indicator (CII) is also a part of this strategy.

Crucially, the EEXI framework remains impartial to technology choices, allowing shipowners and charterers to adopt the most suitable methods for complying with IMO regulations. Notably, wind-assisted propulsion emerges as a dependable solution for existing vessels, an endorsement recognized by IMO itself.

3. Technological Advancement

Wind propulsion technology falls into seven categories: rotor sails, suction wings, hard sails, soft sails, kites, turbines, and innovative hull forms. Let's delve into these innovations and their potential.

• Rotor Sail: Rotor sails, like the Flettner Rotor, consist of rotating composite cylinders with top and possibly bottom discs. These discs, turned by low-power motors, utilize the Magnus effect to generate thrust as the wind catches the rig.

• Suction Wing: Suction wings, including Ventifoil, Turbosail, and eSAIL, feature non-rotating wing sails equipped with vents and internal fans that create suction, enhancing their effect.
• Hard Sail: Rigid sails employ stiff materials and encompass various systems, such as wing sails, foils, and JAMDA-style rigs, some with single or multiple foils, and even solar panels for added power generation.

• Soft Sail: Soft sails offer diverse configurations, ranging from traditional sail rigs to modern designs like the dynarig system, which has seen extensive use in both commercial and leisure sailing.
• Kite: Kites, positioned over 200 meters above the vessel, attach to the bow to aid propulsion. They harness constant high-altitude winds and can be passive or dynamic, offering the potential for electrical energy generation through their tether.
• Turbine: Marine-adapted wind turbines are used to generate electrical energy or a combination of energy and thrust, with both vertical and horizontal configurations being developed.
• Hull Form: Hull form designs integrate the ship's structure as a large 'sail,' capturing wind power for thrust, primarily suited for newbuild vessels.

As wind propulsion technology advances, so does the development of testing procedures, energy management systems, weather routing software, and the integration of digital/satellite-enabled wind data. These systems are fully automated and seamlessly integrated into ships' energy management systems.

The performance of a ship retrofitted with wind propulsion is typically measured by observed "fuel savings." However, this percentage is often derived from standard motor ship profiles without considering optimization factors like weather routing or speed variation, which are essential for maximizing wind propulsion performance.

Past assessments of wind propulsion solutions have overlooked crucial aspects, such as optimizing wind systems, focusing excessively on retrofit designs, underestimating the potential of wind systems across a fleet, undervaluing their energy provision potential, and neglecting considerations related to materials, support systems, automation, and innovative approaches in dealing with air draft.

4. Advantages and Economic Benefits

Leveraging primary renewable energy, such as wind power, directly for ships stands out as one of the most efficient applications of renewable energy sources. In a future where energy resources are constrained, optimizing energy use directly makes perfect sense. With virtually zero emissions during operation and a consistently low or zero fuel cost for propulsion throughout a ship's operational lifespan, this technology becomes a crucial choice for ship owners aiming to ensure their fleets comply with emission regulations.

The cost of harnessing wind energy is directly linked to the technology itself, and ongoing innovations continue to drive down costs and enhance efficiency. It's safe to say that the expenses associated with maritime wind technology will inevitably follow a path of cost reduction, once it surpasses the initial phase of innovation.

Wind-assisted propulsion systems (WAPS) have the potential to significantly reduce fuel consumption, ranging from 5% to 9%, and in certain cases, even up to 25%. The exact level of reduction depends on the specific system, vessel type, and route. These reductions result in automatic cost savings for operational aspects and, importantly, lead to substantial cuts in greenhouse gas emissions. Additionally, they contribute to the reduction of other pollutants, like nitrogen oxides and sulfur oxides, thereby improving Environmental Efficiency Existing Ship Index (EEXI), Energy Efficiency Existing Ship Index (EEDI), and Carbon Intensity Indicator (CII) ratings.

Moreover, WAPS systems extend their environmental benefits beyond emissions reduction. Technologies like wing sails and kites play a role in mitigating underwater noise pollution, benefiting marine ecosystems.

5.?Regulatory Developments

Since the inception of first-generation projects that displayed promising outcomes, it became evident that there was a need for regulatory frameworks, especially considering WASP when calculating the Energy Efficiency Existing Ship Index (EEDI). Consequently, numerous technical, regulatory, and policy documents and proposals were presented at subsequent meetings of the Marine Environment Protection Committee (MEPC). These submissions aimed to address adjustments to EEDI, operational metrics, and the International Maritime Organization's Data Collection System (DCS).

Based on thorough studies and actual outcomes, it was clear that the EEDI improvements achieved through WAPS systems fell significantly short of the actual fuel savings realized during operations. Several factors contributed to this underestimation:

• Varying wind conditions across different global regions, a factor overlooked in the application of the global wind probability matrix. However, this approach facilitates the comparison of diverse systems.
• The operational speed of ships varies depending on wind conditions, a facet not considered in the EEDI calculation, which only references the EEDI reference speed.
• The implementation of route optimization, allowing for more efficient utilization of WAPS by adjusting routes based on prevailing wind conditions. Unfortunately, this variance is disregarded in the application of the global wind probability matrix.

Ultimately, these endeavors led to an amendment of existing guidelines, culminating in the most recent version: the "2021 Guidance on the Treatment of Innovative Energy Efficiency Technologies for the Calculation and Verification of the Attained EEDI and EEXI" (MEPC.1/Circ.896).

6. Integration and other Challenges

The potential benefits of wind propulsion technologies are substantial across various segments of the global fleet. However, each segment presents its unique set of challenges. For instance, containerships contend with limited deck space, geared bulkers grapple with loading and unloading requirements, while cruise ships face air draft restrictions. Wind propulsion technology developers collaborate closely with relevant stakeholders to tailor systems to each segment's specific needs.

For shipowners, making investment decisions can be a complex task when quantifying expected gains proves elusive. Typically, performance is measured by the observed "fuel saving," which is derived from standard motor ship operational profiles, without accounting for factors like weather routing and speed variation that optimize wind propulsion technology. This creates challenges in accurately assessing savings for charter parties.

Another consideration is the weight of wind propulsion technologies and their impact on a ship's displacement. For Energy Efficiency Existing Ship Index (EEDI) calculations, the added weight should be regarded as a loss of deadweight tonnage (DWT). Similarly, permanently added ballast water for IMO Intact Stability criteria due to sail presence should be considered.

Weather and wind routing play a crucial role in enhancing the performance of wind propulsion installations and primary wind-powered ships. They can capitalize on route and speed optimization more effectively than fully motorized vessels. Optimizing both speed and route improves expected fuel savings from wind-assisted systems, although their effectiveness is highest when sailing downwind or with the wind on the beam, and minimal in upwind or calm conditions.

WAPS systems, while efficient, come with complexities and require specialized maintenance, which can increase operational costs. Some, like kites, may pose safety risks if not operated correctly. Addressing air draft and port operations necessitates innovative solutions like folding, retracting, movable systems, and modularity whenever feasible.

Additionally, transversal forces and yaw moments linked to wind propulsion need attention as they can affect a ship's maneuvering and seakeeping performance. Simulations play a vital role in assessing the maneuverability of wind-powered ships from the early design stage.

For wind-powered ships, the traditional speed-power curve isn't sufficient to describe performance. Wind propulsions generate not only thrust but also side forces, resulting in drift and increased rudder angles. This complexity necessitates more transparent performance indicators and prediction methods for the industry.

Installing wind propulsion systems increases a vessel's windage area, which results in greater minimum propulsion power to maintain maneuverability in adverse conditions. However, this could conflict with the aim of wind propulsion systems to provide additional propulsion while potentially reducing the main engine's power. The increased main engine's Specific Maximum Continuous Rating (SMCR) entails additional costs for the entire engine system and can affect shipowners' willingness to adopt wind propulsion systems as a practical means of reducing greenhouse gas emissions from ships.

7. Market Overview and Future Prospects

The adoption of wind-assisted propulsion is still in its initial commercialization phase, with some technologies, like hull form, in the development stage. The wind-assisted propulsion market encompasses various stakeholders, including manufacturers, technology providers, shipbuilders, and shipowners. It's an evolving market, with Europe taking the lead, closely followed by regions like Asia-Pacific, Japan, and China.

Over the forecast period from 2023 to 2032, it is anticipated a substantial uptake of wind-assisted propulsion, particularly in cargo ships, due to the maritime industry's heightened focus on decarbonization initiatives.

Notable developments have occurred since 2020, with growing industry interest in Wind Propulsion Technology (WPT) systems across various segments. This surge has been accompanied by increased research, technology projects, and new installations. As we approach the end of 2023, the International Windship Association (IWSA) forecasts that WPT systems will be integrated into 31 large commercial vessels, including an additional 8 in ready-to-implement conditions. Looking ahead to the first quarter of 2024, this number is estimated to range from 49 to 53, with an additional 12 in ready-to-implement status.

Highlights in the Wind-Assisted Propulsion Market:

• In April 2021, BAR Technologies and Yara Marine Technologies forged an exclusive collaboration to design and deploy wind-assisted propulsion systems for the global shipping sector. This innovative solution, utilizing solid wing sails, holds the potential to deliver fuel efficiency savings of up to 30% to the shipping industry.
• June 2021 saw Alfa Laval and Wallenius unveil their joint venture, AlfaWall Oceanbird, with a 50/50 ownership structure. This venture is dedicated to advancing and implementing technology for entirely wind-powered vessel propulsion.
• In May 2022, Econowind and Vertom jointly announced their partnership to equip multiple vessels with wind-assist VentoFoil units by the end of 2022. Initial installations will take place on the general cargo vessels MV Progress and MV Perfect, marking the first fleet order for Econowind.
• In September 2023, Airbus plans to install new fuel-saving sails for its maritime operations, focusing on one of its vessels chartered from shipowner Louis Dreyfus Armateurs. This technology harnesses wind energy for thrust, resulting in substantial fuel and CO2 emission savings.

8. Final Thoughts

The realm of wind-assisted propulsion is at the cusp of a promising era in maritime innovation. From its initial stages of commercialization to the burgeoning interest across segments, it's evident that wind propulsion technologies are gaining traction. As the maritime industry confronts the critical challenge of decarbonization, the prospects for wind-assisted propulsion, especially in cargo ships, are on the rise since technology stands as a promising means to curb fuel consumption and reduce greenhouse gas emissions in shipping. However, a significant challenge hindering its widespread adoption is the absence of established standards for substantiating its potential in terms of fuel savings. As of now, there exists no standard approach for conducting full-scale verification of wind-assisted technology on commercial vessels.

To address this issue, a comprehensive approach to verify wind-assisted ships in real-world conditions is essential. This entails the implementation of long-term monitoring procedures to obtain precise and reliable outcomes.

Looking ahead, it's crucial to maintain a forward-looking perspective. Future studies should delve into refining the quantification of gains and addressing challenges. Continued technological advancements, collaborations hold the promise of further propelling wind-assisted propulsion's adoption. In this era of sustainability and innovation, wind-assisted propulsion is not merely a technology but a driving force towards a more environmentally responsible and efficient maritime industry. It's a future filled with possibilities, and research, collaboration, and continued advancements will pave the way to a more sustainable, economically viable, and eco-friendly maritime world.

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