Technical Conference: Managing CII and Associated Challenges 2025

Please note that the abstract list may be updated later.

eSAILs©: Using Wind to Improve Real Vessel CII and Environmental Performance
Simone Saettone, Performance Department, Bound 4 Blue S.L., Spain

Co-Authors:
Elias Boletis, Enarete Marine, Sr. Advisor Bound 4 Blue S.L., Netherlands
Jan Arne Opedal, Odfjell, Project Manager, Norway
Lisa Martinez, Performance Department, Bound 4 Blue S.L., Spain
Nathalia Batalha, Performance Department, Bound 4 Blue S.L., Spain
Enrique Vilanova Vidal, Performance Department, Bound 4 Blue S.L., Spain
Javier Zamora, Performance Department, Bound 4 Blue S.L., Spain
David Ferrer, Performance Department, Bound 4 Blue S.L., Spain

Maritime pollution has been a central concern for the International Maritime Organization (IMO) for several decades, with a clear shift toward more sustainable practices. Various regulatory measures, including the Sulphur Cap, Energy Efficiency Existing Ship
Index (EEXI), Energy Efficiency Design Index (EEDI), Carbon Intensity Indicator (CII), European Union Emissions Trading System (EU ETS), and FuelEU Maritime, are being implemented to accelerate the decarbonization of the maritime industry. Despite these efforts, the industry faces substantial challenges, including the demand for greater emissions reductions, the limited availability of alternative fuels at the necessary scale, and the lack of mature decarbonization technologies. Addressing these challenges requires innovation from both charterers and shipowners.
Wind-Assisted Propulsion Systems (WAPS) are emerging as a promising solution, given their considerable potential to reduce vessel fuel consumption and contribute to decarbonization goals. The eSAIL©, a WAPS technology developed by Bound4blue, exemplifies this trend. It is a high-lift device capable of achieving lift coefficients of up to 8.3, providing significant savings potential with reduced sizes.
This paper presents the expected improvements in CII and environmental performance achieved by a real vessel equipped with eSAILs©, based on operational data.

Wing Sails and Weather Routing for CII Compliance: A Liner and Tramp Route Study
James Mason, Smart Green Shipping

In 2023, the International Maritime Organisation (IMO) introduced the Carbon Intensity Indicator (CII) to curb carbon emissions from shipping. To comply with the CII, particularly during this decade, ship owners will increasingly need to implement new efficiency-saving devices, change operational practices, and install innovative forms of propulsion.

Wind propulsion with weather routing presents one such solution, where wind-assist devices such as wing sails work in synergy with optimal routing strategies to enhance fuel and carbon savings for ships. However, while studies highlight that wind propulsion and weather routing can significantly reduce carbon emissions on routes across the globe, there is more limited knowledge of the extent to which these technologies can affect a ship’s CII rating.

In this research paper, we use Smart Green Shipping’s scientifically verified FastRoute weather routing software to calculate CII reductions for a Panamax bulk carrier on a liner route in the North Atlantic and while tramping. By simulating hundreds of historical voyages using hindcast weather data, we show that ship owners can improve their annual CII score by up to two ratings using wing sails alone. Moreover, we show that introducing weather routing to optimise wind performance can improve a ship’s annual CII score by up to 3 ratings. Finally, we provide the first insight into wind propulsion uncertainty while tramping.

Our findings demonstrate how ship owners can install wing sails and use weather routing to drive down carbon emissions and remain compliant with the increasingly strict limits of the CII for longer.

The future of CII in the well-to-wake fuel chain - Foreship
Jan-Erik Rasanen, Foreship Ltd

In parallel with its review of the Carbon Intensity Indicator as a metric to drive decarbonisation in shipping, The International Maritime Organization is formulating mid-term measures to promote the use of zero- and low-emission fuels, with implementation due in 2027.

Based on Life Cycle Assessment, from 2027 this part of IMO’s regulatory framework is expected to align with the ‘well-to-wake’ impact of ship CO2 emissions chosen for FuelEU Maritime legislation, rather than the CII’s ‘tank-to-wake’ approach. While distinct from the methodology used for FuelEU Maritime, this will include CO2 emissions from feedstock to production in its assessment, as well as its use onboard ship.

Subject to its CII review, IMO has options to amend its tank-to-wake indicator so that it better reflects operational profile by ship type, or even to move towards a measure based on audited continuous improvement of energy management.

But can the CII as currently conceived achieve compatibility with ‘well-to-wake’? Can a new method of calculating the CII provide a component part of the LCA approach? Or, given that reaching the IMO’s target for net zero emissions from ships by around 2050, can IMO formulate a workable indicator that transforms the current metric into a measurement of carbon content in fuel based on a well-to-wake approach?

In this presentation, Foreship will draw on its experience of assessing ship performance for CII in its current mode and provide examples of how a possible change to a well-to-wake approach will impact the CII.

Marine Environmental Metrics: Are we Measuring the Right Thing?
John Hatley, Maritex

The IMO target goal of 50% emission reduction by mid-century drives fleet emissions downward according to current regimes.

The Efficiency Existing Ship Index, or EEXI, is based upon technical parameters to predict fuel efficiency of a ship moving through calm water. For existing older hulls lacking supportive data, the IMO established upper maxima for the EEXI based upon a vessel type.
The Carbon Intensity Index, CII, is an “operational measure” as different from a “design measure” exposes why ships of identical designs (EEXI ratings) generate extremely different real-world efficiencies.

This paper illustrates several existing flaws within the Carbon Intensity Index (“CII”) as Charterer operational decisions dominate environmental outcomes where technical features are relegated to secondary roles.
The inherent CII problem for vessel owners is they are not in control of vessel movements when duty bound to obey Charterer commands. This then punishes ships by saddling them with poor CII grades not due to technical shortcomings of the ship, but rather due to the operational trading patterns (short versus long voyages, extensive waiting time, et al.) required to meet Charterer orders.
The CII equation cannot discern between ships of the same technical characteristics who exhibit vastly different Grades resulting from cargo trade routes. Vessels on longer trade routes generate superior scores. However, the total cargo moved annually is far higher for high frequency deliveries on short voyages whose logistics contributions are penalized.
This presentation will identify many operational dynamic requirements that remain outside the perspective technical lens of the engineer designer that illustrate perverse CII outcomes in opposition to the goal of absolute emissions reduction.
• Long versus short voyages
• Days in transit versus port time
• Speed impacts on trade route microeconomics
• Charterer’s desire lower freight prices associated with greater macro capacity that conflicts with CII guidance toward slower speeds.
• Shore power is a rich nation pathway not shared by poor countries lacking adequate electrical grid capacity.
• The CII equation ignores port capabilities and favors modern efficient mechanized cargo operations not found amongst poor nations with primitive infrastructure.
• Vessel speed reductions reduce aggregate transport capacity requiring new buildings to meet transport capacity demand. The CII is blind to the cost of shipyard construction heavy environmental costs.

The Importance of Data Scope and Reliability for The Robustness and Acceptability of The Ship Carbon Intensity Indicator (CII)
Peyman Ghaforian Masodzadeh, World Maritime University

In order to motivate ship operators to reduce their carbon footprint, a well-recognized CII, approved by all stakeholders, is essential. In this regard, relevance (scope) and reliability of the data that feeds the CII are of paramount importance. In the definition of voyage, the inclusion of port turnaround time and waiting time in the voyage time scope has resulted in dissatisfaction among ships engaged in short sea shipping with a high number of port calls. On the other hand, some concerns exist regarding data reliability, such as the possibility of data manipulation, the quality of data verification, the disclosure and transparency of data, and the role of flag states. Additionally, an annual CII rating cannot provide a motivating signal for ship staff. Moreover, two parallel data collection and verification mechanisms, the IMO DCS and the EU MRV, have resulted in confusion and administrative difficulties for shipowners.
By conducting online surveys with the participation of a wide range of stakeholders and interviewing data verifiers, this study attempted to shed light on these issues. Verifiers highlighted the challenges they encounter in data collection and verification. Compared to AER, survey respondents and data verifiers preferred EEOI. A majority of respondents and data verifiers believe that disclosure of actual cargo tonnage (e.g., in EEOI calculations) is not commercially sensitive as long as confidentiality clauses are in place. In conclusion, this study provides some recommendations for improving data collection and verification work in order to achieve a more acceptable CII outcome.

Beyond Carbon Intensity: Enhancing GHG Reductions through an effective EE metric and Regulatory Alignment
Daniel Barcarolo, The Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping

This paper evaluates the effectiveness of the Carbon Intensity Indicator (CII) and examines potential regulatory overlaps that could limit greenhouse gas (GHG) reductions from short- and mid-term measures. Firstly, using operational data from container ships, tankers and bulk carriers, the study identifies a strong correlation between the Energy Efficiency Operational Indicator (EEOI) and capacity utilization, supporting its use as metric to drive operational efficiency. An EEOI Propulsion metric is also analysed to show how it could encourage behavioural shift to maximize voyage performance gains, by isolating energy consumption relating to distance travelled from other activities such as port work. Finally, the potential for a regulatory framework accounting for emissions associated with electrical load and cargo requirements is illustrated by a separate calculation of emissions coming from only auxiliary engines and boilers, both in port and at sea.

Secondly, the paper discusses interactions between short- and mid-term measures, warning that carbon intensity metrics in CII, especially if revised to a well-to-wake basis, may overlap with a Global Fuel Standard, thereby reducing overall GHG reductions through cross-compliance. It notes that the difficulty in quantifying cost savings from operational and technical efficiency measures could disincentivize future investments when a GHG pricing mechanism offers an alternative route to meeting CII targets. To mitigate such risks and encourage future efficiency gains, recommendations are made to adopt an energy-based metric post-2030 to encourage building, maintaining and operating energy efficient ships/fleets. Such an approach highlights the advantages in reducing onboard energy consumption and enhances the effectiveness of the revised IMO GHG strategy.

Evaluation on Energy Savings Effect of Corrective Actions Using Monitoring Operational Data for Ferries
Toshiyuki Kano, NPO Marine Technologist

Reduce the environmental impact of ship operations, various corrective actions are being taken on ships to improve energy efficiency. Improvement effects of corrective actions are evaluated based on measured fuel oil consumption (FOC), but actual FOC measurements vary widely and appear to be difficult to organize and evaluate successfully.
The authors treated the variation in FOC of a voyage by separating it into a time-varying bias term such as hull fouling, a random (noise) term such as wind and waves, and a directional term such as ocean currents/westerly winds. This allows us to evaluate the effect of improvement by comparing the FOC per voyage between the case where no corrective measures were taken and the case where corrective actions were taken, and to confirm the significance level of this evaluation result using statistical testing methods.
In this report, we introduced a case study in which this methodology was applied to a ferry to evaluate the reduction in FOC and CO2 emission reduction when WR as a corrective measure was used and its effectiveness was confirmed and share our experience.
In addition, the operational collecting data will also show the factors why the use of WR has resulted in energy savings. This will allow an action to consider further improvements.
Finally, there is one matter that must not be forgotten when it comes to the practice of energy-saving ship operations. This is the shipping companies and vessels, preferably with the participation of shippers work together as one team to save energy.

Onboard Energy Data as the Key to Operational Optimization and Reporting
Uwe Altenbach, Hoppe Marine GmbH

The integration of precise sensors and timeseries data acquisition through the Maritime Internet of Things (MIoT) paves the way for effective energy balancing and operational optimization. This approach focuses on installing a holistic energy sensing setup and sophisticated data acquisition systems, laying the groundwork for enhanced energy monitoring. Such methodologies are crucial for complying with CII guidelines and preparing for the challenges posed by the EU ETS from 2025 onwards. The integration of Continuous Emission Monitoring Systems (CEMS) and energy measurement devices build the foundation for energy balancing. This allows operational optimization and validated reporting solutions and shows the critical role of data-driven decision-making and reporting in achieving sustainability and efficiency enhancements.

Balancing Energy Efficiency and Marine Biodiversity in the Decarbonization Era
Yigit Kemal Demirel, Hempel A/S

Effective biofouling management strategies offer a significant opportunity to reduce the fuel penalty of ships caused by biofouling, aid in meeting Carbon Intensity Indicator (CII) targets, and advance the decarbonization of the shipping industry. Maintaining a clean hull throughout the docking cycle results in significant energy savings compared to a fouled hull. Additionally, keeping ship hulls clean and managing biofouling growth is vital for preserving marine biodiversity. Choosing a biofouling management strategy involves selecting the appropriate antifouling coating system and corresponding maintenance requirements during its lifetime in the form of in-water cleaning.

This paper argues that the choices entailed in biofouling management activities must balance the trade-offs between emissions to air (i.e. energy and emission reduction from clean hulls) and emissions to water (i.e. passive or accelerated release of waste substances to ensure a clean hull). Therefore, different biofouling management strategies should be evaluated by focusing on their impact on energy efficiency (fuel consumption, GHG emissions and CII) and the water column (emissions from antifouling coatings and in-water cleaning). Simulations conducted on a bulk carrier assess the effects of various antifouling coatings and cleaning practices, offering a holistic perspective on biofouling management. Integrating insights from academic literature, internal data from Hempel A/S, and independent simulations, our study examines the trade-offs involved. Our findings aim to guide ship owners, operators, and policymakers toward practices that enhance energy efficiency while protecting marine biodiversity, thus supporting the maritime industry's efforts to meet CII targets without compromising environmental integrity.

Operational techniques for CII voyage score enhancement in WASP fitted ships
Kostas Fakiolas, FINOCEAN LTD

In WASP fitted ships the voyage CII score can be currently predicted only basis anticipated WASP systems performance response in a given route chosen waypoints on basis of long-term wind weather statistics and assuming the WASP units operate all the time in their optimal settings. The actual factors that impact the real voyage CII score performance will be analysed, and it will be demonstrated how specific operational techniques related to the voyage, propulsion integration and incoming wind management can either improve or even hinder performance despite of the utilization time of the WASP units, if not managed and harmonized appropriately. Especially for ships with large sailing time per year, boosting the operational performance of fitted WASP is paramount to cope with forthcoming stricter CII reduction limits, especially as foreseen beyond 2026. Study case examples will be presented on a couple of representative benchmark cargo ships fitted by WASP units and practical guidelines will be provided for operational CII optimization of WASP fitted ships.

The next version of CII – What might it look like?
Chris Waddington, International Chamber of Shipping

The IMO short Term GHG measures, including the Carbon Intensity Indicator (CII) are within a review and to facilitate this, interested parties have made submissions to IMO that have identified CII system anomalies and have proposed improvements. These were considered at MEPC 82, and it is expected that a correspondence group will continue the analysis of these through to MEPC 83 in April 2025.
This paper will outline industry’s experience with the CII rating system since it came into effect on 1st January 2023. The current status of the CII review will be summarised and details of the identified system anomalies and proposed system improvements will be provided. Possible outcomes of the CII review will be considered, and the potential way forward for the next version of CII discussed.

Blue Visby: Collaborative Arrival Optimization as a Pathway to Carbon Reduction
Haris Zografakis, Stephenson Harwood

Co-Author:
Pekka Pakkanen, NAPA

The Blue Visby Solution introduces a revolutionary approach to emission reduction through coordinated arrival times combined with necessary contractual architecture, significantly addressing inefficiencies in maritime logistics. This presentation details how Blue Visby functions as a digital platform akin to an air traffic control system for maritime routes, optimizing vessel speed and minimizing waiting times at congested ports. Developed through cross-industry collaboration, this platform has already demonstrated its potential to reduce fuel consumption and cut CO₂ emissions. By leveraging data on vessel characteristics, port conditions, and voyage requirements, Blue Visby enables a synchronized arrival system that allows vessels to retain berthing order while operating at more sustainable speeds. The presentation will cover preliminary results from Blue Visby trials, projected emission reductions, and feedback on system design from industry stakeholders.

Integrating Hardware and Software Solutions for Enhanced CII Performance: A Case Study from Kowa marine and NAPA
Kentaro Abe, QHSE Leader of Kowa Marine
Pekka Pakkanen, NAPA

In response to the urgent need to reduce emissions and improve the Carbon Intensity Indicator (CII) performance, this presentation offers an in-depth analysis of initiatives undertaken by Kowa Marine, under Nissen Kaiun's Technical Management company, in strong partnership with NAPA.
Company has been at the forefront of deploying operational enhancements and advanced voyage optimization software to meet CII targets.
This session will explore the approach that combines state-of-the-art highly efficient ships with NAPA’s digital tools, highlighting the application of NAPA Voyage Optimization in real-world settings.
NAPA Voyage Optimization leverages sensor data collected onboard to fine-tune vessel models, delivering data-driven guidance for more efficient voyage planning. Additionally, Company is planning to integrate "Blue Visby" to optimize vessel arrival times, reducing unnecessary idling and emissions. These technologies allow vessels to navigate with minimized fuel consumption, mitigate adverse weather impacts, and further enhance CII ratings.
Company has adopted a comprehensive strategy, employing both hardware and software interventions to tackle CII challenges and contribute to a more sustainable maritime future.
We will present the results from recent optimization trials, detailing conditions, execution, and outcomes, alongside estimated CII improvements.
In conclusion, this presentation will highlight the effectiveness of advanced software and methods like Blue Visby in achieving CII improvements, alongside traditional hardware solutions. The collaboration between Kowa Marine and NAPA underscores a proactive approach in the maritime industry, emphasizing that operational measures, backed by suitable software, are crucial in meeting decarbonization targets.

Monitoring and Analyzing to Enhance the Efficiency and Sustainability Onboard a Ro-Pax Vessel
Ivana Melillo, Energy Efficiency Director, GNV

Co-Authors:
Abbo Alida, Energy Manager, GNV
Michela Schenone, Head of Projects, RINA
Arianna Lamberti, Marine Digital Solutions Analyst, RINA

In the context of the International Maritime Organization's (IMO) greenhouse gas emissions reduction strategy, the Carbon Intensity Indicator (CII) has been introduced to measure and reduce the carbon intensity of shipping operations.
The IMO has set ambitious targets to achieve significant reductions in carbon emissions by 2030 and 2050. These targets are crucial for driving the maritime industry towards more sustainable practices and ensuring compliance with global environmental standards.
This study aims to understand how far the actual vessel performance of the newbuild GNV Polaris Ro-Pax vessel is from the estimated one at design phase, during its first trip, focusing on both overall performance and propulsive performance.
GNV Polaris is part of GNV Fleet, founded in 1992, part of the MSC Group. GNV is one of the leading shipping companies operating in the coastal and passenger transport sector worldwide and is undergoing a modernization program which entails the delivery of four new Ro-Pax vessels with energy efficiency high standards.
GNV Polaris is an innovative vessel due to its advanced design and cutting-edge technology. GNV, in cooperation with RINA and using SERTICA Performance, is focusing on monitoring and optimizing the energy and environmental performance of their ship during its journey from China to Europe, arriving in Genoa.
The primary objective of this study is to determine the optimal engine settings for commercial operations, ensuring enhanced efficiency and sustainability.
GNV Polaris, a RO-Pax vessel with a gross tonnage of approximately 47,000 tons, integrates advanced technologies for emission reduction, energy efficiency, and passenger comfort. During the voyage, various configurations of engine settings and speeds were tested, allowing for a comprehensive analysis of propulsion efficiency and fuel consumption.
The study found that the vessel’s innovative propulsion systems and energy efficiency measures significantly reduce operational emissions and CII. The adoption of shore connection for cold ironing and advanced energy recovery systems highlights the industry's shift towards sustainability.
The methodology used in the study involves creating performance curves based on voyage sailing conditions and comparing the estimated performance with actual data. Additionally, the study utilizes a white box digital twin to provide a detailed description and analysis of the vessel's performance. This approach allows for a comprehensive understanding of the factors influencing the vessel's efficiency and offers insights into potential areas for improvement.
The SERTICA Performance software used in this study provides seamless integration with external systems, enabling real-time data ingestion from existing data collection systems. It aggregates data in 5-minute intervals, enriches it with weather data, and performs performance calculations and metrics.
Leveraging also on the ability of creating hydrodynamic digital twins, this system helps in evaluating the real effectiveness of technological improvements and supports decision-making for energy efficiency and technical solutions.
Data collected during the voyage were continuously logged and analyzed, confirming the vessel's performance metrics against sea trial benchmarks. This analysis provides valuable insights into optimizing engine settings, contributing to the vessel’s sustainable operations, and enhancing the overall passenger experience.
The findings underscore GNV Polaris as a pivotal addition to GNV's fleet modernization and environmental responsibility strategy, setting a benchmark for future maritime projects.
As a ferry operator we strongly believe that GNV can be a steering actor of energy transition of the ferry sector, providing more sustainable ways of transport and bringing its needs to decisional tables.
Digitalization plays a key role in the cooperation between shipowners and supplier, in order to meet  IMO targets by enabling real-time monitoring, data analysis, and optimization of vessel operations. It helps in achieving and maintaining compliance with regulations, monitoring efficiency, and implementing retrofitting actions based on real return on investment.

Effective Biofouling Management Strategies: The Challenges With Ship-Specific Functional Specifications and Coating Selection
Ralitsa Mihaylova, Safinah Group

Developing effective biofouling management strategies for different vessels is challenging due to the variability in operating parameters, activity profiles, and trade-specific requirements. Selecting the optimal system, or a combination of systems, for a specific ship is a complex task as there are multiple options to choose from.

Data on the in-service performance of biofouling control products independently collected through dry dock project supervision can be used to enhance the coating selection and specification process.

The presentation aims to introduce a data-driven approach to coating selection and specification that allows for continuous learning and serves as the basis for an evidence-based biofouling management strategy. The findings include insights on product and scheme performance based on more than 800 dry dock projects and over 600 specification reviews, as well as challenges with implementing a ship-specific approach to biofouling management and common misconceptions regarding product selection and expected performance.