Air Lubrication System (ALS) with Microbubbles Reduces Ship Resistance

An Air Lubrication System (ALS) is an air-lubrication technology that creates a layer of air beneath the ship’s hull, reducing resistance. Depending on ship design, this can be achieved through air bubbles, integrated air chambers or hybrid principles, which all lower the friction of the near-hull water flow. Our selected partner applies an ALS that distributes ultra-fine microbubbles along the hull. The bubble cloud uses the Kelvin-Helmholtz instability to remain stable, which in practice reduces hydrodynamic resistance. Sea trials and operational data indicate average fuel savings of about 5 to 15 percent, depending on ship type, loading condition and speed. Exact values are route-specific and depend on operating conditions and system configuration. As a result, carbon dioxide (CO₂) emissions can also be reduced in many cases.

How Microbubble Technology in Air Lubrication Contributes to Energy Efficiency

The air lubrication system lowers flow resistance by releasing controlled microbubbles along the ship’s hull, reducing the overall water force. This technology creates the basis for structural efficiency gains and fuel savings, depending on hull shape, speed, loading and sea state. It makes air lubrication a sustainable solution for both deep-sea and short-sea shipping, applicable to retrofits and newbuilds. Once approved by class societies and flag-state authorities, the technology can be applied worldwide to a wide range of ship types, including bulk carriers, container ships, tankers, cruise ships, roll-on/roll-off (RoRo) vessels, RoPax ferries and car carriers.

The core of this effect lies in the boundary layer, the thin film of water that flows directly along the hull and where most resistance occurs. By injecting sub-millimeter microbubbles, smaller than 1 millimeter, into this layer, hydrodynamic resistance can be reduced significantly. This resistance is usually the largest energy-loss factor in propulsion.

To control bubble formation, the system uses wing profiles based on standardized NACA shapes, designed by the National Advisory Committee for Aeronautics. These profiles guide the flow efficiently and ensure a stable air flow and even bubble distribution. When the bubbles reach the boundary layer, the Kelvin-Helmholtz instability occurs. The velocity difference between air and water creates vortices that mix the air and form a stable air cloud along the hull.

The combination of optimized NACA profiles and the Kelvin-Helmholtz process makes it possible to maintain a stable air cloud. As a result, the lubrication effect remains effective, even with variations in loading, speed or sea state. The outcome is repeatable performance that reduces resistance and improves ship energy efficiency, both in model tests and under operational conditions.

For shipowners, shipping companies and technical managers this translates into clear advantages: lower fuel costs, structural energy savings and measurable reductions of greenhouse gas emissions across the global fleet. To make these benefits verifiable, documentation and measurement methods such as ISO 15016 play a central role. In addition, class approval and flag-state recognition are essential for the formal acceptance of performance claims.

Microbubbles and Hull Resistance: The Optimizing Effect

The efficiency of this air lubrication technology depends not only on generating microbubbles, but mainly on how they influence the flow along the hull. Once the bubbles enter the boundary layer, the interaction between water and air changes, reducing resistance and creating efficiency gains in practice.

This effect occurs because the injected microbubbles lower the wall shear stress, the frictional force the water exerts on the hull. This reduces turbulence in the boundary layer and decreases friction. At the same time, buoyancy pushes the bubbles against the hull, forming a stable air cloud that acts as a protective buffer and reduces resistance further.

A natural illustration can be seen in penguins. They trap air under their feathers to increase hydrodynamic efficiency and move faster through the water. This biomimetic principle is technically reproduced and applied in maritime air lubrication systems.

The scientific foundation was established in laboratory tests with flat plates, later refined with Computational Fluid Dynamics (CFD) analysis, model testing and sea-trial measurements following international standards such as ISO 15016 and ISO 19030. This layered body of evidence bridges theory and practice, showing that microbubble technology can deliver repeatable energy savings and emission reductions in international shipping under varying loading, speed and sea state conditions.

Advantages of Air Lubrication Technology (Air Cloud)

Air lubrication technology based on a continuous air cloud functions under diverse sea and weather conditions without negative impact on operational efficiency. This technology can deliver structural fuel-cost reductions and measurable CO₂ reductions, regardless of the fuel type used. These benefits are directly linked to the way the system leverages natural flow dynamics. The interaction between water and air along the hull forms the basis for efficiency and energy savings.

In shallow-water sailing up to several meters of depth, hydrofoil-based configurations can guide the water flow so that air is passively drawn in. In such cases, little or no compressor power is needed because the flow itself generates the bubbles. At greater depths or specific sailing profiles, depending on speed and draft, compressors provide additional air to maintain a stable air cloud. As a result, the energy demand remains limited in most sailing conditions, and the net effect is positive, with fuel savings exceeding compressor consumption.

A lower energy demand also directly improves reliability. This approach results in a simpler and more cost-efficient design with fewer wear-sensitive components, lower maintenance needs and higher operational availability. In practice, this can extend service life and reduce the risk of unplanned downtime. For fleet managers and superintendents this means performance can be reliably translated into operational efficiency, maintenance planning and compliance.

The advantages go beyond fuel savings and emission reduction. The air cloud acts as a barrier between hull and water, making it harder for marine organisms to attach. At the same time, changes in shear stress in the boundary layer and higher oxygen levels create an environment less favorable for fouling. The result is a cleaner hull, reduced cleaning frequency and consistently low ship resistance. Air lubrication technology therefore not only supports daily operational efficiency but also facilitates the use of alternative fuels in the future, because the total energy demand remains structurally lower.

Waste Heat Recovery for Compressed Air Supply

The efficiency of air lubrication and the potential for fuel savings can be further increased by combining the technology with waste-heat recovery. Heat that would otherwise be lost through exhaust gases, engine cooling water, residual steam or thermal oil is converted into electrical energy for the compressor that supplies air for microbubble injection. In this way, the additional energy demand is largely covered internally and sustainably, which strengthens the net effect and improves both the energy and emissions balance.

The technical core is formed by installations based on the Organic Rankine Cycle (ORC). These systems convert waste heat efficiently into electricity and typically deliver 100 to 200 kW net per module, depending on engine output and energy demand. Thanks to the modular design, multiple units can be combined, so that total electric power in specific projects can reach about 1,000 kW. This creates an integrated configuration in which waste-heat recovery and air lubrication reinforce each other, making proven efficiency improvements possible under operational conditions.

The policy relevance directly connects to the frameworks of the International Maritime Organization (IMO). A first benchmark is the Carbon Intensity Indicator (CII), which calculates how much CO₂ a ship emits per transported ton of cargo and per nautical mile. Since air lubrication reduces fuel demand, the emissions intensity also decreases, making a more favorable CII rating achievable. The Energy Efficiency Existing Ship Index (EEXI) is another key measure, focused on the design side. By combining air lubrication and waste-heat recovery, the energy consumption per unit of power falls, helping ships meet EEXI requirements without major engine restrictions or large-scale retrofits. This makes the system relevant not only for policymakers and regulators but also for technical management responsible for the Ship Energy Efficiency Management Plan III (SEEMP III) and Monitoring, Reporting and Verification (MRV) reporting.

The same applies within the European framework. Under the Emissions Trading System (EU ETS), shipping companies must purchase allowances for their CO₂ emissions. Lower fuel consumption translates directly into lower compliance costs. At the same time, FuelEU Maritime raises requirements for the share and intensity of sustainable fuels such as e-methanol, green ammonia and hydrogen. For hydrogen, several logistical options exist, including the use of Liquid Organic Hydrogen Carriers (LOHCs), which facilitate transport and storage. By reducing energy demand through air lubrication and waste-heat recovery, the use of these fuels becomes more practical and economically viable.

This connection from technology to policy is reinforced by formal recognition. The IMO classifies air-bubble technologies as Innovative Energy Efficiency Technology (MEPC.1/Circ.815, Category B-1). This confirms that the path to higher ship energy efficiency not only delivers repeatable results but is also secured within regulatory frameworks.

Installation Process

Air lubrication technology based on a stable air cloud can be integrated both in newbuilds and as retrofits on existing ships at shipyards worldwide. Up to about four meters of water depth, the system functions without a compressor. At greater depths, additional compressed air is needed to keep microbubble injection effective. Hydrofoils are used to control the distribution of air. These wing profiles are designed according to NACA standards, closely aligned with the water flow, and ensure an even distribution of bubbles along the hull.

Air mixing chambers are connected to these hydrofoils to distribute compressed air before injection. These chambers are carefully mounted on the sides of the ship’s hull and efficiently connect the external air supply to the internal installation. Internal components are located in the engine room, where both the compressor and the cloud-based monitoring system are installed. This separation between external and internal elements increases feasibility, reliability and ease of maintenance.

After technical preparation, formal assessment follows. The design has been reviewed by an internationally recognized classification society and granted an Approval in Principle (AiP). This confirms the safety and functionality of the system and formally recognizes its use in international shipping.

Air Lubrication System (ALS) with Microbubbles Reduces Ship Resistance

Discover our selected partner’s air lubrication system and see how this technology contributes to more sustainable, efficient and environmentally friendly shipping.

Introduction

How Microbubble Technology in Air Lubrication Contributes to Energy Efficiency

Microbubbles and Hull Resistance: The Optimizing Effect

Advantages of Air Lubrication Technology (Air Cloud)

Waste Heat Recovery for Compressed Air Supply

Installation Process

In Practice

The implementation of microbubble-based air lubrication on seagoing ships has delivered valuable insights. A concrete example is a ferry equipped with this technology. Operational data shows that under representative conditions a fuel saving of about 10 percent can be achieved. This confirms the effectiveness of the system in daily operations and demonstrates that the investment can be repaid in less than five years, depending on fuel prices and routes. For fleet managers in short-sea shipping and the ferry sector, this means a predictable business case with proven efficiency gains and lower operational risks.

In Practice

FAQ on Air Lubrication with Microbubbles (ALS): Technology, Regulation, Funding and Operational Deployment

These Frequently Asked Questions (FAQ) provide a complete overview of how air lubrication with microbubbles (Air Lubrication System, ALS) contributes to the decarbonization of shipping. By lowering hydrodynamic resistance, the required propulsion power is reduced, which in many cases results in lower fuel consumption and emissions. This can translate into reduced costs under the European Emissions Trading System (EU ETS), easier compliance with FuelEU Maritime, and better scores for the Energy Efficiency Existing Ship Index (EEXI) and the Carbon Intensity Indicator (CII). For shipowners and shipping companies of various vessel types, including RoPax ferries, bulk carriers, tankers, and cruise vessels, it becomes clear that one technical measure can deliver not only operational gains but also financial and regulatory value.

The FAQ also addresses the broader context of applying air lubrication with microbubbles. Topics include operational integration on board and in port, requirements from classification societies and international safety codes, and embedding within the International Safety Management (ISM) system and the Ship Energy Efficiency Management Plan III (SEEMP III). Technical validation and the need for a complete audit trail are also covered, with reference to ISO 15016 (standardized sea trials), ISO 19030 (operational trend analysis), and the MRV dataset (Monitoring, Reporting and Verification). This shows how technology, compliance, and governance reinforce each other in daily practice, and how the net effect, fuel savings minus compressor power demand, can be consistently documented.

Finally, this FAQ explores the financial and regulatory framework for wider adoption. European and national subsidies, fiscal incentives, port fee reductions, and corridor programs are placed in the context of state aid rules, the EU Taxonomy, and private financing such as sustainability-linked loans and green bonds under the Poseidon Principles. The outcome is an integrated perspective where technology, regulation, funding, and operations come together. The goal is to support the development of a legally robust and future-proof fleet.

Regulation and Compliance

How Does an Air Lubrication System (ALS) Reduce My EU ETS Costs?

Core: EU ETS costs can decrease when an Air Lubrication System (ALS) with microbubbles delivers demonstrable net fuel savings and therefore lower reported CO2 emissions. The reduction is recorded through the MRV dataset, provided that the ALS energy balance is validated (compressor demand converted into g/kWh) and traceable. Under EU ETS, depending on routes and loading conditions, this can significantly reduce both the number of required EU Allowances (EUAs) and the related cash outflow.

Detailed: Since 2024, the European Emissions Trading System (EU ETS) has priced CO₂ emissions from seagoing vessels above 5,000 GT performing commercial voyages within or to the European Economic Area (EEA). The basis for this levy is the Monitoring, Reporting and Verification dataset (MRV dataset). Emissions from intra-EEA voyages count fully, emissions from voyages between the EEA and third countries count at 50%, and emissions from at-berth operations are fully included. The implementation is phased: in 2024, 40% is charged, in 2025 this rises to 70%, and from 2026 onwards 100% applies. The first surrender deadline, when shipping companies must hand in emission allowances, is set at 30 September 2025.

Air lubrication with microbubbles (ALS) lowers hydrodynamic resistance and therefore reduces fuel consumption. In practice, this can lower reported CO₂ emissions in the MRV dataset, which directly reduces the need for EUAs. However, the net effect must always be taken into account: fuel savings minus the electricity demand of compressors and auxiliary systems. This energy use must be verifiably recorded and converted into grams of CO₂ per kilowatt-hour (g/kWh), ensuring a fully consistent and reproducible energy balance.

The EU ETS cost is calculated as: reported CO₂ emissions (tons) × scope factor × phase-in percentage × EUA price (€/ton CO₂). The scope factor is 1 for intra-EEA voyages and at-berth emissions, and 0.5 for voyages between the EEA and third countries.

An example illustrates this effect. If a vessel reports 120,000 tons of CO₂ annually in 2025, then at a 70% phase-in percentage and an EUA price of €80/ton CO₂, the EU ETS cost amounts to about €6.72 million. If air lubrication with microbubbles (ALS) delivers a net reduction of 5% in this case, the annual surrender obligation could decrease by around €0.34 million. This calculation reflects only the EU ETS costs; ALS investment and operational costs are not included.

The actual outcome depends on route profile, loading, trim, sea and wind conditions, engine settings, and data quality. ISO 15016 therefore prescribes normalization procedures and uncertainty analysis so that reductions are recorded consistently and with statistical validity. Legally, conditional wording remains required, and certification is always subject to approval by classification society and flag state.

This calculability makes it possible to include EU ETS savings and CO₂ reductions in cash flow projections, provided that the MRV audit trail is fully intact. The audit trail means the complete traceability of raw measurement data, calculations, and corrections up to the final EU ETS report. It is essential that the effects of air lubrication with microbubbles (ALS) are documented in both the monitoring plan (MP) and the Ship Energy Efficiency Management Plan III (SEEMP III). These documents define measurement methods, data sources, corrections, fallback procedures, and responsibilities. When MP and SEEMP III are kept aligned, consistency is maintained between measurements, MRV reporting, and EU ETS settlement. This increases compliance predictability and reduces the risk of disputes during audits.

How Does Air Lubrication Count Under FuelEU Maritime?

Core: Air lubrication with microbubbles (ALS) can count under FuelEU Maritime because it reduces energy use per nautical mile and improves CO2e intensity. This effect applies only after verification of the net energy balance (in g/kWh) and inclusion in the MRV dataset. Under certain conditions, subject to verifier acceptance, this can create more compliance flexibility through banking or pooling and reduce overall compliance costs.

Detailed: The FuelEU Maritime Regulation sets limits from 2025 on the greenhouse gas intensity of energy used on board. This is measured well-to-wake, from source to combustion, expressed in grams CO₂ equivalent per megajoule (g CO₂e/MJ), compared to a reference value of 91.16 g CO₂e/MJ. An ALS does not change the chemical composition of the fuel, but it does reduce the required energy per nautical mile. This can improve the average intensity value, provided that the Monitoring, Reporting and Verification dataset (MRV dataset) maintains the same data quality and consistency as required under the EU Emissions Trading System (EU ETS). For every calculation, the net effect must be included, which is fuel savings minus compressor electricity demand, converted into grams of CO₂ per kilowatt-hour (g/kWh). The technical benefit counts toward compliance only when the data chain is reproducible and accepted by an independent verifier.

FuelEU Maritime also allows flexibility mechanisms to better use performance gains. A surplus can be carried over to the next year through banking. A deficit can be compensated with future performance through borrowing. Multiple ships can pool their results within one portfolio. When ALS delivers a verifiable surplus in the first year, this can be reallocated in a later year to another route or across the fleet, provided that it is registered in the FuelEU Maritime database and confirmed by an independent verifier. Every shift must remain fully traceable and withstand audit review.

An example shows the potential impact. At an annual energy use of 1.0 petajoule (PJ) and a reference value of 91.16 g CO₂e/MJ, the emissions total about 91,160 tons of CO₂ equivalent. If ALS reduces the net energy use by 5% under identical operational conditions and after validation, the annual intensity can decrease to about 86.6 g CO₂e/MJ. ISO 15016 and ISO 19030 prescribe that reductions must be normalized and recorded with uncertainty margins, so that the outcome remains legally valid. This calculation covers only emission intensity; ALS investment and operational costs are not included.

For reductions to count, both the monitoring plan (MP) and the Ship Energy Efficiency Management Plan III (SEEMP III) must be aligned. Only then does the MRV dataset connect seamlessly with FuelEU Maritime reporting. By strategically using banking, borrowing, and pooling, reductions through air lubrication can not only lower EU ETS compliance costs but also support the intensity targets of FuelEU Maritime. This demonstrates how air lubrication with microbubbles enables one technical measure to deliver both compliance value and financial benefit.

What Is the ALS Effect on EEXI and CII?

Core: An air lubrication system (ALS) can reduce the calculated engine power for EEXI if it is demonstrably supported and accepted by the flag state. For CII, the effect becomes visible only when fuel reductions are consistently recorded in MRV and DCS data under verification. In this way, ALS can contribute both at design level and in daily operations to CO2 reduction and lower compliance costs.

Detailed: The Energy Efficiency Existing Ship Index (EEXI), introduced in 2022, assesses whether the design of existing ships complies with set efficiency requirements. An ALS can be included through the pathway for innovative technology, provided that it is convincingly proven that the system reduces the required design engine power.

This justification must be based on calculations and test data reviewed by a classification society and remains subject to flag state acceptance. The evidence typically includes Computational Fluid Dynamics (CFD), model tests, and normalized sea trial data according to ISO 15016, with uncertainty margins. Documentation must transparently record all assumptions, such as hull roughness, loading, trim, seakeeping profiles, and the ALS technical configuration (air flow, nozzle layout, and compressor demand). Only when the net effect, fuel savings minus compressor demand, is verifiable can the reduced engine power be included in the EEXI calculation.

The Carbon Intensity Indicator (CII), introduced in 2023, evaluates annual operational carbon intensity in grams of CO₂ per ton-mile (g/ton-mile). The calculation is based on the International Maritime Organization (IMO) Data Collection System (DCS). Here the impact of an ALS can be directly observed, provided that reductions are consistently recorded in both the Monitoring, Reporting and Verification dataset (MRV dataset) and the DCS dataset, and included in SEEMP III. Lower fuel use reduces the numerator of the CII calculation, while the transport work in the denominator remains constant. For ships with a limited CII margin, this can be decisive, but only if the MRV audit trail is complete and reductions are confirmed by an independent verifier.

In practice, air lubrication is often combined with other measures that further reduce resistance or energy use, such as engine-power limitation, speed management, and biocide-free coatings. Additional energy-saving devices (ESDs) can also be applied, such as the Pre-Swirl Stator (PSS), Pre-Duct, Propeller Boss Cap Fin (PBCF), Twisted Rudder, and Rudder Bulb, which optimize flow around the propeller and improve propulsion efficiency. Wind-assisted propulsion, such as suction sails or Flettner rotors, can deliver further fuel and CO₂ reduction.

To avoid double counting, the marginal contribution of each measure must be transparently allocated. An annual waterfall analysis supports this process and clarifies the marginal cost per ton of CO₂ avoided. This approach ensures that air lubrication is translated into legally valid compliance value both in the design file (EEXI) and in the operational rating (CII). It also makes it possible to secure the technology not only technically but also contractually, for example in charterparties or financing agreements.

When Do Class and Flag State Accept an ALS Performance Claim?

Core: Class and flag state accept an ALS performance claim only when design, installation, and operation are formally approved. This requires type approval, sea-trial data in line with ISO standards, and a complete audit trail, subject to flag state verification. Once recognized, ALS can be included in SEEMP III and compliance documentation, resulting in predictable and legally valid reduction value.

Detailed: Without formal recognition by the classification society (class) and the flag state, no emission reduction from an air lubrication system (ALS) is accepted within international compliance frameworks. Therefore, design, installation, and operational logic must be documented in an approved design and safety file. This includes electrical schematics, compressor requirements, air distribution, backflow and relief safeguards, emergency-stop procedures, and integration into the International Safety Management (ISM) system.

Class normally reviews strength and fatigue analyses of piping and mounting points, electromagnetic compatibility (EMC), noise levels, and operational limits under heavy seas or ice conditions. These elements are covered in type-approval documents, factory and onboard tests, and a sea-trial report under pre-defined conditions. Performance claims must be supported by normalized sea-trial data according to ISO 15016, trend analyses according to ISO 19030, and a complete audit trail of the net effect, meaning fuel savings minus compressor demand. This standardized justification makes the reduction legally verifiable and audit-proof.

The flag state then decides whether the class-validated documentation suffices for formal recognition of performance and safety. This can lead to ALS being included in the Ship Energy Efficiency Management Plan III (SEEMP III) and, where relevant, in compliance files for frameworks such as FuelEU Maritime. Certification remains conditional and always depends on recognition by both class and flag state, including possible additional requirements such as anti-icing procedures or limitations in case of low electrical supply.

By planning this process early and consulting with the independent verifier already in the design phase regarding adjustments to the monitoring plan (MP), consistency is maintained between measurements, MRV reporting, and compliance settlement. This approach ensures smoother alignment with EU ETS, FuelEU Maritime, and CII, while making the business case predictable and legally secure.

Does ALS Impact NOx Certification or IAPP Status?

Core: An air lubrication system (ALS) does not change the NOx emission factor, but it can affect the load distribution through load shifts. Under certain conditions, with normalized data and defined operating envelopes, the validity of NOx certification and IAPP status is preserved. This ensures that fuel savings remain legally usable without emission risks.

Detailed: An ALS does not interfere with the combustion process and does not alter the primary emission parameters of nitrogen oxides (NOx). Indirectly, however, it can influence the validity of NOx certification and the International Air Pollution Prevention Certificate (IAPP). This occurs through load shifts: with lower hydrodynamic resistance, less engine power is required at a given speed, which means that the engine operates more often in a lower load range than during the original type approval test.

For NOx certification, the representativeness of the test cycle under ISO 8178 is decisive. A significant shift in the average load profile can raise questions about the applicability of the original measurements. While the emission factor in grams per kilowatt-hour (g/kWh) remains unchanged, the pattern per load point can differ. Therefore, reductions achieved with ALS must be recorded in normalized form, and the system’s operating envelopes must be explicitly described in the documentation. This clarifies that reduced fuel consumption results from hydrodynamic efficiency improvements rather than from engine modifications, which keeps the Technical File legally valid.

This requires that operating envelopes are documented both in the monitoring plan (MP) and in the records for class and flag state. These documents must specify the speeds, loading conditions, and trims under which the ALS is active and how this affects the main engine’s power range. Any deviation from the baseline must be normalized to a representative point within the original test cycle.

Transparency toward verifiers and inspectors is also essential. Including compressor logs, power curves, and operating envelopes makes the indirect impact of an ALS traceable and reproducible. This ensures that, during audits and Port State Control inspections, shipowners can prove that IAPP certificates remain intact and compliance remains consistent. As a result, NOx certification stays robust, and fuel savings are legally and operationally usable without risk.

Monitoring, Datasets and Reporting

How Do I Safeguard an Audit Trail from Sea Trial to MRV, DCS and FuelEU Maritime?

Core: An audit trail is safeguarded by one consistent dataset from sea trial through MRV and DCS reporting, under verification by class and flag state. SEEMP III defines measurement points, normalization, and fallback procedures, so that the same data flow into EU ETS and FuelEU Maritime. This makes reductions reproducible and avoids compliance risks or financial uncertainty.

Detailed: The foundation of an audit-proof application is one consistent dataset that supports the entire reporting chain. It starts with sea-trial and operational measurements carried out in line with international standards, particularly ISO 15016 for standardized sea trials and ISO 19030 for operational trend analysis. Any deviation from these methods must be recorded conditionally and always remains subject to approval by class and flag state.

Next, Monitoring, Reporting and Verification (MRV) reports are compiled. Here, the strict order of data sources must be respected: first mass-flow meter, then mass balance, and finally Bunker Delivery Note (BDN). The same data are then included without change in the International Maritime Organization (IMO) Data Collection System (DCS). To ensure consistency, the Ship Energy Efficiency Management Plan III (SEEMP III) documents the ALS control logic, measurement points, data quality controls, normalization steps, and fallback procedures in case of data gaps.

Every performance claim must be formulated quantitatively and conditionally. An example is a fuel saving of 6.2% at 75% of maximum continuous rating (MCR), measured according to ISO 15016 and confirmed by a recognized classification society. This claim must always be linked to the specific ship configuration, route, and prevailing seakeeping conditions. Deviations are recorded as boundary conditions, and the net balance is recalculated, including the electrical compressor demand converted into grams of CO₂ per kilowatt-hour (g/kWh). Only then does a complete energy balance emerge that is legally defensible.

With this approach, a single dataset can consistently serve the EU Emissions Trading System (EU ETS), the FuelEU Maritime Regulation, and the Carbon Intensity Indicator (CII), while the Energy Efficiency Existing Ship Index (EEXI) remains based on the design file. Inconsistencies in definitions or data flows almost automatically lead to corrections or rejection by independent verifiers.

The value of this data discipline goes beyond one project. A fleet that standardizes ALS data can scale up faster, maintain predictable compliance balances, and strengthen its position within credit and sustainability frameworks such as sustainability-linked loans. This way, a technical measurement approach develops into a strategic portfolio method in which technical performance, legal validity, and financial value are inseparably connected. This section addresses only compliance and reporting conditions; ALS investment and operational costs are not included.

How Do I Correctly Allocate Compressor Power Consumption (Auxiliary Loads)?

Core: Compressor power consumption can be allocated as an auxiliary load through logged electrical demand, converted into fuel and CO2e, provided that it is verified and accepted by the flag state. Use the specific fuel consumption of the generator and the fuel emission factor (well-to-wake, covering the entire chain) for MRV and DCS. The net effect equals propulsion savings minus compressor energy. All assumptions must be recorded in SEEMP III, so that EU ETS costs can be reduced and compliance remains predictable.

Detailed: The effectiveness of an air lubrication system (ALS) can only be legally recognized if the system boundary is fully closed. This means not only recording fuel savings in propulsion, but also including the electrical power consumption of the compressor. This auxiliary load must form part of the energy balance and must be explicitly allocated under all compliance frameworks, including the Monitoring, Reporting and Verification (MRV) system, the International Maritime Organization (IMO) Data Collection System (DCS), and the FuelEU Maritime Regulation.

In practice, compressor demand is recorded as additional electrical load on the auxiliary engines. Measurement points are usually located at the distribution panel feeding the compressor. Data logging at short intervals, ideally per minute, shows absorbed power, operating hours, and the load profile. These data are then converted into grams of fuel per kilowatt-hour (g/kWh), based on the specific fuel consumption of the generator or main engine that powers the electrical grid. In this way, a consistent link is established between electrical energy demand and the fuel account as recorded in MRV and DCS reporting.

Under FuelEU Maritime, compressor consumption is also fully included, since the regulation calculates greenhouse gas intensity on a well-to-wake basis. This requires that auxiliary load demand is translated into the emission factor of the fuel producing the electricity. If the compressor is powered by a shaft generator running on heavy fuel oil (HFO), the HFO factor applies. For alternative fuels such as LNG or methanol, the corresponding fuel chains apply. This results in a closed balance where the net reduction is the difference between fuel savings from lower hydrodynamic resistance and the additional energy consumption of the compressor.

The net effect is recognized only when the calculation sequence is transparent and reproducible. It begins with determining gross savings, measured during sea trials at 75% of maximum continuous rating (MCR) according to ISO 15016 and confirmed by a recognized classification society. The auxiliary load balance is then calculated by multiplying logged compressor consumption by the generator’s specific fuel consumption and the emission factor of the fuel used. The net saving is the difference between these two values and is expressed in a single closed g/kWh balance. By documenting all assumptions, normalization steps, and fallback procedures in both the monitoring plan (MP) and SEEMP III, the independent verifier can assess and legally validate the entire data chain.

This approach makes ALS reductions audit-proof under all relevant frameworks. Lower CO₂ emissions become visible in the MRV dataset, resulting in fewer allowances to surrender under the European Emissions Trading System (EU ETS). At the same time, a lower fuel intensity improves the well-to-wake score under FuelEU Maritime and strengthens the operational rating under the Carbon Intensity Indicator (CII). By systematically converting the net effect into a g/kWh balance, a legally and technically robust basis is established, which not only satisfies auditors but also provides a predictable foundation for cash flow projections, financing contracts, and compliance analysis.

How Do I Avoid Double Counting with Coatings, Speed Management and Engine Power Limitation (EPL)?

Core: Double counting is avoided by transparently allocating the marginal effect of each measure. ISO 15016 and ISO 19030 prescribe how normalization and separation are carried out. The Ship Energy Efficiency Management Plan III (SEEMP III) records the allocation, so that reductions can be linked separately to ALS, coating, speed management and engine power limitation. This makes the result legally audit-proof and usable for EEXI, CII, EU ETS and FuelEU Maritime.

Detailed: Ships rarely rely on a single energy-saving measure. Air lubrication systems (ALS) with microbubbles are often combined with hull coatings, speed management and engine power limitation (EPL). If all measures are reported together without distinction, there is a risk of double counting, in which the same fuel saving is claimed under multiple headings. This undermines the legal validity of the compliance balance and creates uncertainty for both shipowners and verifiers.

International standards provide guidance on how to separate the effects. ISO 15016, focused on sea trials, and ISO 19030, focused on operational monitoring, both prescribe normalization and baseline correction. With coatings, the effect is often measured as a reduced hull-resistance coefficient under identical conditions. With ALS, the net effect is measured as reduced compressor-corrected propulsion demand. With speed management, the marginal effect is the difference in fuel use between agreed speed profiles. With EPL, the effect is calculated by comparing the EEXI value with and without the limitation of maximum continuous rating (MCR).

The transparent allocation of these measures is recorded in SEEMP III. This document defines which savings are allocated to coating, which to ALS, which to speed management and which to EPL. This results in a so-called waterfall analysis in which the combined fuel saving is broken down into marginal contributions per measure. By expressing the cost per ton of CO₂ avoided for each contribution, a marginal-cost calculation is created that supports both compliance and investment decisions.

A practical example illustrates this. Suppose a ship achieves 15% total fuel saving. After correction, it appears that 6% comes from a biocide-free coating, 5% from ALS, 2% from speed management and 2% from EPL. By recording these percentages transparently in the monitoring plan (MP) and SEEMP III, both the independent verifier and the flag state can see that each effect is properly allocated, with no overlap. This ensures that the reductions count legally under EEXI, CII, EU ETS and FuelEU Maritime, and that the business case is predictable and robust.

Which MP And SEEMP III Amendments Are Mandatory Before And After The Sea Trial?

Core: Before the sea trial, the monitoring plan (MP) must already define the measurement method, sensors and compressor consumption, subject to verification. After the sea trial, ISO 15016 results, normalizations and fallback procedures are formally incorporated into the MP and SEEMP III. This keeps the data chain closed and ensures that reductions are recognized in an audit-proof way in MRV, DCS and FuelEU Maritime.

Detailed: An air lubrication system (ALS) can be recognized within the compliance chain only when the effects are recorded in a timely and complete way in the monitoring plan (MP) and the Ship Energy Efficiency Management Plan III (SEEMP III). The amendment procedure makes a strict distinction between the pre-implementation phase and the phase after sea trials.

In the pre-implementation phase, the MP must be amended before the system is made operational. This includes the description of measurement methods, sensors, the data chain and how compressor consumption and fuel saving are recorded as an integral whole. If this is omitted, reports risk rejection by the independent verifier because they are not calibrated against procedures established in advance.

After the sea trials are completed, the post-trial phase follows, in which the results are formally incorporated into the MP and SEEMP III. The outcomes of ISO 15016 tests, the normalizations and sensor calibration are recorded here. The monitoring plan must contain a complete audit trail, including fallback procedures in case primary sensors fail. A fallback can consist of mass balance or bunker delivery notes, but only when the priority of measurement methods is explicitly defined. This hierarchy, also called the QA/QC structure, forms the core of a verifiable data chain.

The minimum requirements for the MP are broadly defined. First, all relevant sensors and measurement points must be described, including accuracy classes and calibration intervals. Second, the plan must record quality controls (QA/QC), in particular how data are validated, how deviations are identified and how corrections are applied. Third, the document must contain fallback procedures that determine how reporting continues in case of data gaps or system failures, without jeopardizing the consistency or legal validity of the dataset.

A critical success factor is synchronization with SEEMP III. This document describes the ship’s operational strategy and must fully align with the MP, so that reductions from an ALS are safeguarded both technically and organizationally. For example, when the MP specifies that compressor consumption is measured with specific sensors, SEEMP III must list the same measurement points and verification procedures in the operational logic. By keeping these documents aligned, one closed chain is created toward MRV, DCS, EU ETS and FuelEU Maritime.

When amendments are made only afterwards, after operational periods have already started, shipping companies risk that the verifier declares the data invalid because the documentation is lagging behind the facts. By submitting amendments on time, before implementation or directly after the sea-trial phase, this risk is eliminated. This prevents delays in certification and financial frictions in the calculation of emission allowances or intensity targets.

This systematic and pre-planned amendment procedure ensures that air lubrication is not only technically effective, it is also integrated in a legally robust way into the compliance and financing structure of a ship or fleet.

How Do I Record Operational Limits And Exceptions In MP/SEEMP III?

Core: Operational limits of an ALS must be recorded in advance in the monitoring plan (MP) and incorporated in parallel in SEEMP III. Exceptions, such as ice navigation or shallow water, are flagged so that reductions do not enter MRV or DCS data. This keeps the scope clear and ensures that performance claims are legally sustainable and audit-proof.

Detailed: An air lubrication system (ALS) delivers measurable emission reductions under normal sailing conditions. Performance can deviate in extreme conditions such as icing, shallow water or high swell. To prevent these exceptions from causing audit discussions or unjustified claims, operational limitations must be recorded in advance and documented in a structured way in the monitoring plan (MP) and in SEEMP III.

The principle is that the scope of the performance claim is delineated ex ante. The MP describes explicitly under which conditions performance is valid and when data fall outside scope. Examples include minimum water depth at full load, maximum wave height or limitations during ice navigation. These limits are recorded based on type-approval documentation, sea-trial reports and recognized class requirements.

In SEEMP III these operational limits are integrated into control logic and data quality procedures. When the ALS operates outside the defined operating envelope during a voyage, for example during prolonged sailing through shallow channels or under ice-class conditions, the associated measurement data are flagged automatically. This ensures that reductions do not enter the MRV or DCS dataset and prevents auditors from correcting or rejecting data.

An additional procedure applies to fouling. Since biofouling increases hydrodynamic resistance and thus affects the relative reduction, the fouling status must be recorded periodically in inspection reports or hull condition assessments. By including this status in the normalization procedure according to ISO 19030, the comparison between ALS and non-ALS periods remains fair and reproducible.

Finally, the MP must describe a fallback procedure if exception conditions are not recorded in time or in full. This procedure determines how data gaps are supplemented or excluded, for example by using average reference conditions or by temporary extrapolation. This safeguards the continuity of the dataset and strengthens legal validity toward auditors and regulators.

By defining operational limitations and exceptions at an early stage, documenting them and linking them to SEEMP III, a consistent audit trail is created. This prevents performance in exceptional conditions from being disputed and gives both shipowner and regulator certainty that reductions are attributed only within the agreed scope.

Audits, Safety and Contracts

What Do Port State Control/THETIS-MRV Request On Board?

Core: Port State Control and THETIS-MRV request type approval, sea-trial report, current monitoring plan and verifier correspondence on the spot. Inspectors also check logbooks and sensor data, including compressor logs and fallback procedures, so that reductions remain transparent and legally valid. This reduces discussion and prevents performance from being rejected during inspections.

Detailed: Port State Control (PSC) and the European THETIS-MRV system apply a strict assessment framework in which the evidence supporting an air lubrication system (ALS) must be directly available on board. Inspectors expect all fundamental documents to be presented immediately. This includes the Approval in Principle or type approval, the as-built documentation of the installation, the complete sea-trial report in accordance with ISO 15016 and the current versions of the monitoring plan (MP). In addition, correspondence with the independent verifier must be available, for example confirmations of measurement methods or approvals of fallback procedures. Without this documentation, the validity of emission reductions can be questioned and there is a risk that performance will not be recognized within the official compliance framework.

Besides the formal documents, operational evidence is required to support system performance in real time. This includes logbooks and digital exports of sensor data, including fuel consumption, air quantity, pressure settings and compressor logs with power uptake. Inspectors check whether measured values align consistently with MRV reports and whether the audit trail is fully traceable. When deviations are present, the shipowner must demonstrate how these were detected and corrected.

A particular focus is on data gaps. The monitoring plan must contain an explicit fallback hierarchy that describes exactly which method is used when primary measurements are temporarily unavailable. The usual order is mass-flow meter first, then mass balance and only as a last resort the bunker delivery note. This hierarchy must be recorded consistently in both the MP and SEEMP III, so that the verifier can confirm data provenance and legal validity remains intact.

By structuring all documents and logbooks in advance and organizing fallback procedures clearly, the likelihood of discussion during PSC inspections is significantly reduced. THETIS-MRV includes only verifiable datasets, which makes any deviation or correction directly visible in the official report. Those who safeguard this process carefully can show convincingly during inspections that the air lubrication system not only functions technically, it is also integrated in a legally sound way within the compliance structure.

Which Safety Studies Are Required For An ALS Retrofit?

Core: For an ALS retrofit, formal safety studies are mandatory, including HAZID, HAZOP and FMEA, under supervision of class and the flag state. These analyses translate risks into design adjustments, emergency-stop logic and maintenance tasks, so that the installation remains safe and reproducible. As a result, the retrofit can be accepted legally and operationally without audit friction.

Detailed: In a retrofit of an air lubrication system (ALS), safety ranks on par with performance and compliance. The process therefore starts with formal risk studies that systematically identify and mitigate installation and operational risks. In practice this means a HAZID to inventory hazards and scenarios, followed by a HAZOP to elaborate process deviations, failure modes and barriers per subsystem, supplemented by an FMEA to quantify component-level risks and prioritize mitigation measures. Together, these analyses form the justification for the classification society and the flag state. Findings are conditionally translated into design adjustments, operating limits and maintenance tasks. This creates a closed safety basis that matches the technical and operational reality of the specific ship.

A crucial outcome of these studies is the sizing and placement of check and relief provisions in the air piping and distribution chambers. Check valves prevent unwanted water ingress or air backflow during stops. Relief provisions limit pressure build-up in case of blockages, icing or erroneous configurations. At the same time, class requires verification of electromagnetic compatibility and noise levels because compressor and control logic introduce electrical and acoustic emissions that can affect other ship systems. Where relevant, limits for sea state and ice conditions are also established, so that control logic automatically scales down or shuts off when the ship operates outside the safe envelope. This makes the technical barrier chain concrete, reproducible and verifiable.

The emergency-stop logic deserves explicit attention. The operating concept must include a hierarchy of safe shutdown, with clear priorities for compressor, valves and air chamber segments, and with verifiable fallback to a safe state in case of power loss or signal faults. Class generally requires a description of set points, alarms, interlocks and permissions, including test procedures for periodic testing during port stays and planned dry-dock periods. By linking the emergency-stop philosophy to bridge and engine control routines, including clear roles and tasks for watch and engineering crews, operational clarity is safeguarded. This increases safety and audit resilience during Port State inspections.

All safety measures are recorded conditionally in the operating and maintenance manual approved by class. The manual contains the operational limits for sea state and ice, the tolerance bands for pressure and flow in the air piping, the mandatory inspection intervals for valves, piping, attachment points and sensors, and the test frequency of alarms and emergency-stop functions. The maintenance programs also describe calibration intervals and criteria for replacement or overhaul of critical components, with explicit reference to findings from HAZID, HAZOP and FMEA. By keeping these documents aligned with the monitoring plan and SEEMP III, the technical safety logic remains consistent with the data chain used for MRV, DCS, EU ETS and FuelEU.

This integrated approach prevents safety from becoming an appendix separate from the project. The risk studies steer the detailed design. The check and relief provisions secure the primary barriers. EMC and noise verification protects the interface with other systems. The emergency-stop logic defines safe behavior in case of deviations, and the manual anchors the whole in daily procedures and periodic maintenance. This enables the flag state to grant conditional acceptance based on demonstrable control, while class includes the requirements in operational documentation and the maintenance program. This line from risk identification to formal assurance makes the retrofit safer and legally and operationally predictable, so that implementation and later audits can proceed without friction.

How Do I Record ALS Performance In Charterparties And Performance Clauses?

Core: ALS performance can be recorded in contracts by defining ISO 15016 and ISO 19030 data, supplemented by MRV data, as the measurement basis. Net effects must be calculated including compressor consumption in g/kWh and distinguished from other measures through waterfall allocation. This makes performance claims legally enforceable and charterparties predictable without double counting or interpretation conflicts.

Detailed: Contractually anchoring the performance of an air lubrication system (ALS) is essential to prevent discussions between owner and charterer and to link incentives unambiguously to demonstrable results. The core lies in translating technical performance claims into legally enforceable provisions that align with recognized standards and compliance frameworks.

A first requirement is that the measurement method is recorded explicitly. Reductions are determined only on the basis of standardized sea-trial data according to ISO 15016 and operational trend analyses according to ISO 19030, supplemented with MRV data where relevant. The clause describes which data sources are leading, for example mass-flow meter as the primary source with fallback to bunker delivery note, and how normalization is carried out for loading, trim and sea state. This prevents measurement differences or data gaps from causing interpretation conflicts.

The definition of the net effect must be unambiguous. The electrical consumption of compressors is fully offset against the measured fuel saving, expressed in grams of CO2 per kilowatt-hour (g/kWh). Only the corrected balance can be used for the calculation of claims or incentives. This calculation is contractually linked to waterfall allocation, so that double counting with other efficiency measures, such as advanced coatings or engine power limitation, is transparently avoided.

To make financial and operational impact predictable, clauses are usually structured with caps and floors. A cap stipulates that the ALS contribution counts for a maximum percentage in charter claims, while a floor ensures that reductions below a minimum threshold are not claimed contractually. The period over which measurements are taken, for example quarterly or annual averages, must also be defined explicitly to dampen fluctuations due to short-term conditions.

Exclusions are necessary. The clause clearly stipulates that performance outside standardized conditions, such as extreme ice navigation, prolonged off-hire or compressor failure beyond the owner’s control, does not count in the performance balance. This prevents parties from submitting claims based on circumstances outside the control of the ALS.

By working out this contractual translation carefully and basing it on ISO standards, MRV definitions and waterfall allocation, a robust framework emerges. This framework makes air lubrication performance legally enforceable and financially transparent. Both owners and charterers gain certainty and the technology can be incorporated without friction in charterparties and performance clauses.

Do Ports And Corridors Provide Co-Financing For Air Lubrication?

Core: Ports and corridors can provide co-financing or port fee discounts for ALS, provided that performance is independently verified and in accordance with ISO standards. Programs in Rotterdam, Antwerp and Singapore link support directly to MRV-consistent reductions. This makes air lubrication not only technically valuable, it also makes it commercially strategic through lower costs and better market access.

Detailed: Ports worldwide are playing a more active role in stimulating emission-reduction technologies. For shipping companies and shipowners, this means that an air lubrication system (ALS) is no longer only a technical choice, it also directly influences the operational and commercial position of their ships. By linking incentives to demonstrable performance, port authorities translate sustainability into tangible advantages in daily operations.

In Europe this can be seen in Rotterdam and Antwerp, where air lubrication systems can be included in programs for sustainable fleet renewal. The benefits often consist of reduced port fees or additional subsidies, provided that reductions are convincingly and independently verified. Outside Europe, Asian ports are also increasingly adopting this model. Singapore and Busan have corridor projects in which multiple ships jointly achieve emission reductions. This increases performance predictability and creates synergy between ports, shipping companies and logistics chains.

For you as a shipowner, this is strategically important. An air lubrication solution becomes more than a technical measure, it opens the door to more favorable contract terms, better berths or even priority in port operations. This creates a direct link between technology and market access. The ALS concept then becomes a lever that strengthens efficiency and competitiveness.

These opportunities come with strict conditions. Port authorities generally require that performance be substantiated with sea-trial data in accordance with ISO 15016 and operational trend analyses according to ISO 19030. In addition, the report must fully align with the Monitoring, Reporting and Verification (MRV) dataset. Only when this data chain is closed and verifiable is there certainty that co-financing will be paid and that legal validity toward regulators and credibility with investors will be safeguarded.

Differences In Subsidy Conditions For Newbuild Vs. Retrofit?

Core: In newbuilds, an ALS can often be substantiated with CFD models and model tests, which makes subsidy conditions relatively flexible. Retrofit projects require ship-specific sea-trial data, ISO-standard analyses and a safety file under class and flag-state supervision. This often increases opportunities, but the evidence and audit requirements are stricter and legally heavier.

Detailed: In newbuild projects, an air lubrication system (ALS) can be integrated into the ship concept from the design phase. Grant providers generally accept substantiation based on Computational Fluid Dynamics (CFD) models, model tests and standardized sea-trial data. Because the technology is integrated at the drawing-board stage, technical risks are assessed as lower and applications often align with European programs such as the Innovation Fund or Horizon Europe. In this context, air lubrication can be submitted at a Technology Readiness Level (TRL) of 6 to 8. The technology then moves from validation in a controlled environment to application under operational conditions.

In retrofit projects, the burden of proof is higher. Reductions must be substantiated with ship-specific sea-trial data in accordance with ISO 15016, supplemented with operational trend analyses according to ISO 19030. Integration into an existing hull must be recorded in a detailed safety file that is assessed by the classification society and formally recognized by the flag state. Since retrofit measures are directly reflected in the MRV dataset and thus in the EU ETS and FuelEU Maritime, grant providers impose additional requirements on normalization of data for loading, trim and seakeeping conditions.

At the same time, many schemes focus on retrofit measures because these accelerate the decarbonization of the existing fleet. This increases opportunities, but also tightens conditions. A closed monitoring plan and a transparent audit trail are indispensable to prevent reductions from being corrected or rejected later by auditors.

For you as a shipping company, applications are promising only when the distinction between newbuild and retrofit is recognized early and translated into the project file. By integrating technical evidence, the compliance structure and safety documentation accurately from the start, delays and rejections can be prevented and predictability of award increases significantly.

Subsidies, Financing and Insurance

Which Subsidies And Fiscal Instruments Are Relevant?

Core: Relevant support for ALS can include EU programs such as the Innovation Fund, Horizon Europe and CEF Transport, provided that reductions are demonstrable and verifiable. Nationally, fiscal instruments such as MIA, Vamil and EIA apply, depending on inclusion on the Environmental List and timely notification to the RVO. This makes air lubrication more feasible financially. Approval always remains subject to the authorities, class and the flag state.

Detailed: An air lubrication system (ALS) can be supported within the European Union through various grant programs and fiscal instruments, provided that the project meets formal conditions and remains within the applicable state-aid framework. The General Block Exemption Regulation (GBER) is guiding here. Support may be granted only when there is no overcompensation and when the investment demonstrably contributes to emission reduction. For shipping companies and shipowners, a carefully prepared project file is indispensable. The file must comprise sea-trial data in accordance with ISO 15016, transparent cost references and a monitoring plan in line with ISO 19030. Only when this structure demonstrably meets the requirements of auditors, regulators and the Netherlands Enterprise Agency (RVO) does a realistic chance of award arise.

Within the European context, several programs take a central position. The Innovation Fund supports large-scale projects that convincingly reduce greenhouse gas emissions and directly align with the objectives of the EU ETS. For retrofit projects with an air lubrication solution, this means that reductions in tons of carbon dioxide (CO2) must be substantiated precisely and must be reproducible in the MRV dataset. Horizon Europe (2021 to 2027) provides space for research and demonstration projects. For an air lubrication technology, validation of CFD models, supplemented with model tests and sea trials, often takes center stage. In that context, the technology can be submitted at a Technology Readiness Level (TRL) of 6 to 8. Laboratory research and model tests are then completed and application in operational situations is being validated. The Connecting Europe Facility (CEF) Transport is also relevant, especially for ships that are part of the Trans-European Transport Network (TEN-T). When air lubrication is combined with port-based energy infrastructure or corridor projects, CEF financing can be decisive.

In addition to these European schemes, actual accessibility is often determined nationally. In the Netherlands, the Environmental Investment Allowance (MIA) and the Random Depreciation of Environmental Investments (Vamil) are available, provided that the technology is listed on the annual Environmental List, published in the Government Gazette, and is notified to the RVO on time. Depending on the configuration, the Energy Investment Allowance (EIA) may also apply, provided that the energy saving is demonstrably sustainable and fully recorded in engineering packages, quotations and measurement reports. For shipping companies and shipowners, it is crucial that these notifications are submitted carefully and on time, since incomplete submission or late notification automatically results in loss of entitlement.

Financial institutions play an important role in the bankability of the ALS concept. The European Investment Bank (EIB) provides long-term loans and guarantees for projects that demonstrably contribute to maritime decarbonization and fit within the EU Taxonomy. Export Credit Agencies (ECAs), such as Atradius DSB in the Netherlands, reduce the risk profile through export credit insurance and guarantees. For shipping companies and shipowners, investments in an air lubrication system become more feasible financially and more firmly anchored legally. Final approval does, however, remain dependent on formal approval by the competent authorities and on recognition by both the classification society and the flag state, which makes early alignment essential to achieve predictable results.

Which Foreign Subsidies Are Available?

Core: Foreign subsidies for ALS include programs at BAFA (Germany), Enova (Norway), NEDO (Japan) and South Korean shipbuilding schemes. Singapore also provides co-financing through corridor projects, provided that reductions are ISO-compliant and verifiable. Early alignment with local authorities and class increases the likelihood of award and strengthens global competitive advantage.

Detailed: Beyond Dutch and European programs, several foreign subsidy initiatives are relevant to an air lubrication system (ALS). For shipping companies and shipowners with internationally operating fleets, this can be important because national support programs often align directly with the strategic objectives of the maritime sector. By exploring these opportunities early, the business case for an air lubrication solution is strengthened and the predictability of investment returns increases.

Germany illustrates this with subsidies managed by the Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA), focusing on shipping projects that demonstrably contribute to decarbonization. Norway, through Enova, provides substantial support, but only if emission reductions are convincingly substantiated with internationally recognized standards such as ISO 15016 for sea trials and ISO 19030 for operational trend analysis. Japan supports the development and application of energy-saving maritime technologies through the New Energy and Industrial Technology Development Organization (NEDO). South Korea links subsidies to its national shipbuilding strategy, which makes the ALS concept particularly promising in newbuild projects or serial fleet-renewal programs.

Additional opportunities arise in Asian hubs such as Singapore, where co-financing schemes target ships that frequently operate along regional trade routes and in local ports. For shipping companies and shipowners, this can be decisive, since access to support often depends on the flag registry or on whether a vessel demonstrably operates within a defined corridor. In this way, national support measures are connected to international corridor projects, which increases the scalability of this air lubrication technology and further strengthens its commercial value.

A continued success factor in foreign subsidies is mutual recognition of standards. European standards such as ISO 15016 and ISO 19030 are internationally acknowledged within the IMO and ISO framework. Additional national verification requirements may still apply. For shipping companies, early consultation with local partners, classification societies and independent verifiers is essential to keep the alignment between European and national evidence airtight.

When foreign subsidies are used effectively, the result is additional financial room and a strategic competitive advantage. In markets where governments actively invest in green shipping technology, an air lubrication system can be applied earlier and scaled faster. For shipping companies and shipowners this increases the commercial value of this air lubrication solution worldwide, while it strengthens alignment with compliance requirements and access to sustainable finance.

How Does Air Lubrication Fall Under The EU Taxonomy For Sustainable Finance?

Core: Air lubrication can fall under the EU Taxonomy when reductions are reproducible and supported by ISO standards, under supervision of class and the flag state. Taxonomy-compliant recognition opens access to green bonds and sustainability-linked loans, provided that MRV and EU ETS data provide a closed audit trail. This means ALS strengthens efficiency and bankability and strategic market position.

Detailed: Within the EU Taxonomy, the European framework for sustainable finance, economic activities are recognized as sustainable only when they demonstrably contribute to emission reduction and energy efficiency. For an air lubrication system (ALS), this is directly relevant, the technology reduces fuel consumption structurally and therefore carbon dioxide (CO2) emissions. The condition is that performance is reproducible, supported by ISO 15016 sea-trial measurements and ISO 19030 operational trend analyses, and is formally recognized by both the classification society and the flag state. Only then can an investment in this air lubrication solution be designated taxonomy-compliant.

When that recognition is in place, access to a broader and often more attractive financing market follows. Banks and institutional investors increasingly use the EU Taxonomy as an assessment framework in loan and bond decisions. If the ALS concept meets the taxonomy criteria, this can lead to better access to capital, more favorable terms and a stronger legal basis for the investment decision. This makes an air lubrication system more than a technical measure. It becomes a strategic instrument that strengthens the financial position of a fleet.

Taxonomy-compliant investment also paves the way for sustainability-linked loans and green bonds. In such structures, performance is tied to measurable key performance indicators (KPIs), for example verifiable fuel savings or an improved Carbon Intensity Indicator (CII) score. The durability of this depends on a closed audit trail toward the Monitoring, Reporting and Verification (MRV) system and the European Emissions Trading System (EU ETS). Only when the data chain is fully traceable and controllable do results remain legally robust and credible toward auditors, regulators and financiers.

For you as a shipping company, the system becomes a lever with which you reduce costs, increase access to sustainable finance and strengthen your position within frameworks such as the Poseidon Principles. This shows how an air lubrication solution bridges compliance, technological innovation and strategic financial positioning.

Can ALS Contribute To Sustainability-Linked Loans And Green Bonds?

Core: An ALS can contribute to sustainability-linked loans and green bonds when reductions are ISO-compliant, verified and recognized by the flag state. Banks accept such performance as reliable KPIs, which lowers interest rates and increases bankability. Air lubrication becomes both a technical measure and a strategic financial instrument.

Detailed: In ship finance, sustainability-linked loans and green bonds are gaining importance quickly. Their hallmark is that interest rates and terms are tied directly to demonstrable performance, such as reduction of carbon dioxide (CO2) per ton-mile or an improved Carbon Intensity Indicator (CII) score. For shipping companies, technical measures that make emission reductions legally robust have a direct impact on financing terms.

An air lubrication system (ALS) can contribute directly. When reductions are reproducible, supported by ISO 15016 sea-trial measurements and ISO 19030 operational trend analyses, and are formally recognized by the classification society and the flag state, they can be included as reliable KPIs in financing contracts. For banks and investors, this provides assurance that reductions are technically valid and audit-proof.

For you as a shipowner, this provides a double benefit. Operating costs drop through lower fuel consumption and structural emission reduction. Capital costs improve thanks to more favorable loan conditions, since performance in sustainability-linked loans or green bonds is rewarded with better terms. This turns an air lubrication solution from a technical measure into a strategic financial instrument.

Moreover, the ALS concept helps shipping companies comply with the Poseidon Principles, the framework through which banks assess their portfolios against the decarbonization targets of the International Maritime Organization (IMO). This increases access to international green bond markets and strengthens the strategic value of ALS in global ship finance.

By linking technical performance, compliance frameworks and financial incentives directly, ALS becomes a structural pillar of sustainable and future-proof ship financing.

Which Guarantees And De-Risking Instruments Are There For Financing?

Core: Guarantees for ALS financing are provided by the EIB and ECAs such as Atradius DSB, often in newbuild or fleet roll-out. Retrofit projects can benefit from national guarantee schemes that cover integration and payback risks. With ISO-supported reductions and alignment with EU ETS and FuelEU, a blended-finance structure lowers risk and increases bankability.

Detailed: Besides subsidies and loans, guarantees and de-risking instruments are crucial for making investments in an air lubrication system (ALS) accessible. The European Investment Bank (EIB) offers guarantee schemes that lower the risk profile of maritime projects, for example through project guarantees or portfolio instruments. Export Credit Agencies (ECAs), such as Atradius DSB in the Netherlands, provide credit insurance and guarantees that are decisive particularly in newbuilds or serial fleet roll-out of air lubrication solutions. This encourages banks to finance large-scale or cross-border investments in this technology.

For retrofit projects, national guarantee schemes are often available. These cover specific risks, such as technical integration of an ALS concept into existing ships or the longer payback periods inherent to efficiency measures. Such guarantees create a more attractive risk profile, which makes lending by commercial banks more feasible and cheaper.

Access to these instruments requires a closed project file. Reductions must be supported convincingly by sea-trial data in accordance with ISO 15016, operational trend analyses according to ISO 19030, and proven alignment with IMO and EU regulations such as the EU ETS and FuelEU Maritime. Financial projections must be transparent and must fit the criteria of auditors and regulators. Only then do guarantee schemes become available in practice.

When guarantees are combined with subsidies and long-term loans, a blended-finance structure emerges that is legally valid and financially robust. For you as a shipping company, this strengthens the business case for an air lubrication solution, aligns it with frameworks such as the Poseidon Principles, and creates a pathway to scalable, low-risk investment in green shipping technology.

Does Air Lubrication Count In Insurance Conditions And P&I Coverage?

Core: Air lubrication can count in insurance conditions when reductions are demonstrated in an ISO-compliant way and recognized by class and the flag state. Insurers value lower hydrodynamic load and more predictable cash flows, which can lead to more favorable P&I premiums. ALS delivers advantages technically, financially and in insurance.

Detailed: In the maritime insurance sector, attention to sustainability and operational risk reduction is growing. P&I clubs and specialized marine insurers increasingly link their premium terms to the sustainability profile of ships. For an air lubrication system (ALS), the technology can increasingly be included in the assessment of insurance conditions, provided that reductions are convincingly demonstrated, supported by ISO 15016 and ISO 19030, and are formally recognized by the classification society and the flag state.

An important operational advantage of this air lubrication solution is that hydrodynamic load on the hull is reduced structurally. This leads to a longer lifetime of coatings and a reduced maintenance frequency. For insurers, this is evidence that operational risk decreases because the likelihood of damage, corrosion and unexpected downtime is reduced.

The ALS concept contributes to the financial stability of shipping companies. Through structural fuel and emission reductions, the predictability and robustness of cash flows increase. For insurers, this is relevant because a lower risk profile reduces the likelihood of claims and financial friction. Ships that demonstrably benefit from air lubrication can qualify for more favorable premium terms or additional coverage.

Although the formal inclusion of air lubrication in insurance policies is still developing, trends point clearly in this direction. Initiatives such as the Poseidon Principles for Marine Insurance show that sustainability is increasingly integrated into risk models. Over time, sustainability-linked insurance products are expected to include air lubrication systems explicitly as a recognized measure. The technology then delivers technical and financial benefits and can improve insurance conditions structurally.

How Do Banks And Financiers Assess An Investment In ALS?

Core: Banks assess an ALS at three levels, ISO-based performance, compliance value under EEXI, CII and EU ETS, and alignment with private sustainability frameworks such as the Poseidon Principles. Only with acceptance by class and the flag state are reductions legally valid and financially usable. Air lubrication can then provide access to sustainability-linked loans and more favorable financing terms.

Detailed: Banks and investors usually assess an air lubrication system (ALS) along three interrelated dimensions, technical performance, value within regulation and compliance, and financial implications in their risk models.

The first layer concerns technical performance. Expected fuel savings gain meaning only when they are supported by sea-trial measurements according to ISO 15016 and operational trend analyses according to ISO 19030. These data must also be accepted by a recognized classification society and remain subject to flag-state acceptance. Only with this formal recognition can banks include reductions safely in their technical and financial assessment.

The second layer concerns compliance value. Lower fuel consumption translates into better scores within IMO frameworks such as the Energy Efficiency Existing Ship Index (EEXI) and the Carbon Intensity Indicator (CII), and into a lower need for emission allowances within the European Emissions Trading System (EU ETS). This effect can be calculated in cash flow projections, provided that reductions are recorded consistently and reproducibly in the MRV dataset and form part of a closed audit trail. For financiers, this transparency is essential to guarantee legal validity.

The third layer is alignment with private sustainability frameworks. More banks apply the Poseidon Principles to assess ship finance portfolios against the global decarbonization targets of the International Maritime Organization (IMO). A ship that demonstrably benefits from an air lubrication solution can qualify for sustainability-linked loans. Interest rates and terms improve as predefined KPIs, such as fuel saving or improved CII scores, are achieved.

Through this layered assessment, financiers see the ALS concept not only as a technical innovation. They see it as a strategic instrument that connects performance, compliance and financial value. Air lubrication then becomes a lever that increases operational efficiency and provides access to sustainable finance within the EU Taxonomy and international investment standards.

Air Lubrication System (ALS) with Microbubbles Reduces Ship Resistance

How Microbubble Technology in Air Lubrication Contributes to Energy Efficiency

Microbubbles and Hull Resistance: The Optimizing Effect

Advantages of Air Lubrication Technology (Air Cloud)

Waste Heat Recovery for Compressed Air Supply

Installation Process

Air Lubrication System (ALS) with Microbubbles Reduces Ship Resistance

Introduction

How Microbubble Technology in Air Lubrication Contributes to Energy Efficiency

Microbubbles and Hull Resistance: The Optimizing Effect

Advantages of Air Lubrication Technology (Air Cloud)

Waste Heat Recovery for Compressed Air Supply

Installation Process

In Practice

In Practice

FAQ on Air Lubrication with Microbubbles (ALS): Technology, Regulation, Funding and Operational Deployment

Regulation and Compliance

How Does an Air Lubrication System (ALS) Reduce My EU ETS Costs?

How Does Air Lubrication Count Under FuelEU Maritime?

What Is the ALS Effect on EEXI and CII?

When Do Class and Flag State Accept an ALS Performance Claim?

Does ALS Impact NOx Certification or IAPP Status?

Monitoring, Datasets and Reporting

How Do I Safeguard an Audit Trail from Sea Trial to MRV, DCS and FuelEU Maritime?

How Do I Correctly Allocate Compressor Power Consumption (Auxiliary Loads)?

How Do I Avoid Double Counting with Coatings, Speed Management and Engine Power Limitation (EPL)?

Which MP And SEEMP III Amendments Are Mandatory Before And After The Sea Trial?

How Do I Record Operational Limits And Exceptions In MP/SEEMP III?

Audits, Safety and Contracts

What Do Port State Control/THETIS-MRV Request On Board?

Which Safety Studies Are Required For An ALS Retrofit?

How Do I Record ALS Performance In Charterparties And Performance Clauses?

Do Ports And Corridors Provide Co-Financing For Air Lubrication?

Differences In Subsidy Conditions For Newbuild Vs. Retrofit?

Subsidies, Financing and Insurance

Which Subsidies And Fiscal Instruments Are Relevant?

Which Foreign Subsidies Are Available?

How Does Air Lubrication Fall Under The EU Taxonomy For Sustainable Finance?

Can ALS Contribute To Sustainability-Linked Loans And Green Bonds?

Which Guarantees And De-Risking Instruments Are There For Financing?

Does Air Lubrication Count In Insurance Conditions And P&I Coverage?

How Do Banks And Financiers Assess An Investment In ALS?

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