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Logistics Terms EEXI(Energy Efficiency Existing Ship Index)

Registration dateJUL 05, 2024

EEXI(Energy Efficiency Existing Ship Index)
The Energy Efficiency Existing Ship Index (EEXI) has emerged as a pivotal component in the maritime industry's ongoing efforts to reduce greenhouse gas emissions and enhance energy efficiency. As environmental regulations become increasingly stringent, understanding and complying with EEXI standards is crucial for ship owners and logistics operators worldwide. This blog post aims to demystify EEXI, exploring its significance, calculation methods, compliance strategies, and the challenges and opportunities it presents for the future of ocean transport.
  1. 1) What is EEXI?

    Background of EEXI
    Amendments to the International Convention for the Prevention of Pollution from Ships (MARPOL) Annex VI of IMO(International Maritime Organization) entered into force on 1 November 2022. Developed under the framework of the Initial IMO Strategy on Reduction of GHG Emissions from Ships, which was agreed upon in 2018, these technical and operational amendments require ships to improve their energy efficiency in the short term and thereby reduce their greenhouse gas emissions.

    From 1 January 2023, it became mandatory for all ships to calculate their attained Energy Efficiency Existing Ship Index (EEXI) to measure their energy efficiency and to initiate the collection of data for the reporting of their annual operational carbon intensity indicator (CII) and CII rating. The EEXI aims to set stringent energy efficiency standards for existing ships, encouraging the maritime industry to adopt more sustainable practices and technologies.

    These amendments reflect the International Maritime Organization's (IMO) commitment to reducing the environmental impact of shipping. The IMO's strategy includes various measures and regulations designed to ensure that the industry contributes to global efforts to mitigate climate change. The implementation of the EEXI and the mandatory reporting of CII data are crucial steps in this strategy, providing a framework for continuous improvement in energy efficiency and reduction of carbon emissions across the global shipping fleet.

    EEXI Definition and Target Vessel
    The Energy Efficiency Existing Ship Index (EEXI) focuses on the technical design of a ship, aiming to ensure that existing ships meet minimum energy efficiency standards. The EEXI regulation applies to ships engaged in international navigation with a total tonnage of 400 tons or more, and must be verified by the ship inspection agency to ensure that the EEXI regulation is met by the first ship inspection date arriving after January 1, 2023.

    This attained EEXI is then compared to a required EEXI value, which is determined by factors such as ship type, capacity, and principle of propulsion. The required EEXI represents the maximum acceptable attained EEXI value, ensuring that ships adhere to the prescribed energy efficiency standards.

    The calculation of the attained EEXI is specific to each individual ship, taking into account its unique technical and operational characteristics. Given the various scenarios that can apply, it is crucial for ship owners and operators to verify the applicable scenario for their specific ship to ensure compliance.

    By mandating the calculation and attainment of the EEXI, the IMO aims to improve the energy efficiency of the global shipping fleet. This initiative is a key component of the broader strategy to reduce greenhouse gas emissions from ships, promoting environmental sustainability within the maritime industry.

    EEXI related Images (Source: IMO)
  2. 2) EEXI 계산방법

    The calculation of the Energy Efficiency Existing Ship Index (EEXI) follows the methodology used for the Energy Efficiency Design Index (EEDI), with adaptations to account for existing vessels. The guidelines for calculating EEXI are detailed in several specific resolutions published by the International Maritime Organization (IMO):

    - RESOLUTION MEPC.333(76) 2021: Guidelines on the method of calculation of the attained Energy Efficiency Existing Ship Index (EEXI).
    - RESOLUTION MEPC.334(76) 2021: Guidelines on survey and certification of the attained Energy Efficiency Existing Ship Index (EEXI).
    - RESOLUTION MEPC.335(76) 2021: Guidelines on the shaft/engine power limitation system to comply with the EEXI requirements and use of a power reserve.

    The EEXI describes the CO2 emissions per cargo ton and mile, determining the standardized CO2 emissions related to installed engine power, transport capacity, and ship speed. As a design index, EEXI does not involve any operational data or on-board measurements; it focuses solely on the design parameters of the ship. The calculation of EEXI involves the following components:

    1) Emissions Calculation:
    - Installed Power of the Main Engine: The power output of the main engine.
    - Specific Fuel Oil Consumption (SFOC): The amount of fuel consumed by the main and auxiliary engines, determined from engine test bed results.
    - Fuel Conversion Factor: A factor that converts fuel consumption into corresponding CO2 emissions.

    2) Transport Work:
    - Capacity: Usually represented by the deadweight tonnage (DWT) of the ship.
    - Ship Speed: The speed of the ship as related to the installed power.

    The emissions are calculated based on the installed power of the main engine, the corresponding specific fuel oil consumption of both the main and auxiliary engines, and a conversion factor between the fuel and the CO2 mass. The transport work is determined by the ship's capacity (typically its deadweight) and the ship speed in relation to the installed power.

    It is important to note that the calculation does not consider the maximum engine power. Instead, for most ship types, it uses 75% of the Maximum Continuous Rating (MCR) or 83% of MCRlim (in case of an installed overridable power limitation). The specific fuel oil consumption of the main engine and the ship speed are considered at this specific power level.

    The EEXI calculation is a design-based approach to assessing a ship's energy efficiency, focusing on its potential CO2 emissions per unit of cargo transported per mile, based on the ship's design parameters rather than its operational performance.

    EEXI related Images (Source: Firefly, Adobe)
  3. 3) Process

    The EEXI process involves determining the ship type and size, gathering necessary data, calculating emissions and transport work, and then determining the attained EEXI. Compliance is achieved by comparing the attained EEXI with the required EEXI and implementing necessary measures to reduce emissions if needed. The process culminates in documentation, certification, and a periodical survey to ensure adherence to the IMO regulations.

    [Step 1] Determine the Ship Type and Size
    Identify the ship type and size category, as the required EEXI value varies based on these parameters. This step is crucial for setting the correct benchmark for the calculation.

    [Step 2] Gather Necessary Data
    Collect the relevant technical data needed for the EEXI calculation:
    - Main Engine Installed Power (MCR): The maximum continuous rating of the main engine.
    - Specific Fuel Oil Consumption (SFOC): The fuel consumption of the main and auxiliary engines, typically obtained from engine test bed results.
    - Deadweight Tonnage (DWT): The carrying capacity of the ship.
    - Ship Speed: The design speed of the ship corresponding to 75% of MCR or 83% of MCRlim.

    [Step 3] Calculate the Emissions
    Using the collected data, calculate the CO2 emissions based on the installed power of the main engine and the specific fuel oil consumption. Apply the conversion factor to translate fuel consumption into CO2 mass.
    CO2 EmissiPower×SFOC×Fuel Conversion Factor

    [Step 4] Calculate the Transport Work
    Determine the transport work, which is the product of the ship’s capacity (DWT) and the ship speed.
    Transport Work=DWT×Ship Speed

    [Step 5] Calculate the Attained EEXI
    Calculate the attained EEXI by dividing the CO2 emissions by the transport work.
    Attained EEXI=CO2 Emissions/Transport Work

    [Step 6] Compare with the Required EEXI
    Compare the attained EEXI with the required EEXI value for the specific ship type and size. The required EEXI is determined by IMO regulations and is based on a reduction factor relative to the EEDI baseline.

    [Step 7] Implement Power Limitation if Necessary
    If the attained EEXI exceeds the required EEXI, consider implementing measures to reduce it. One common method is to apply a power limitation system, such as reducing the MCR to 75% or 83% of MCRlim, to lower the CO2 emissions.

    [Step 8] Documentation and Certification
    Document the attained EEXI calculation and any measures taken to achieve compliance. Submit this documentation for review and certification according to the guidelines outlined in RESOLUTION MEPC.334(76).

    [Step 9] Periodical Survey and Approval
    Ensure that the ship undergoes a periodical survey to verify compliance with the EEXI requirements. The ship must attain EEXI approval once in its lifetime by the first periodical survey in 2023 at the latest.

    EEXI related Images (Source: Firefly, Adobe)
  4. 4) Considerations

    Consequences of Not Meeting EEXI Requirements
    All ships are required to have an International Air Pollution Prevention (IAPP) certificate, which from 1 January 2023, must include the EEXI value. If a ship does not meet the EEXI requirements and does not have an attained EEXI value, the IAPP certificate cannot be issued. Without a valid IAPP certificate, vessels are unable to trade legally, which can result in significant operational and financial consequences for the ship owner.

    If the attained EEXI value is below the required target value, the ship owner will need to take corrective actions to improve the vessel's energy efficiency rating. These actions might include:

    - Technical Modifications: Implementing energy-efficient technologies or retrofitting the vessel with more efficient machinery.
    - Operational Changes: Adjusting operational practices to enhance energy efficiency, such as optimizing speed and route planning.
    - Power Limitation: Installing power limitation systems to comply with EEXI requirements and using a power reserve.

    Responsibility for Calculating and Submitting the EEXI Rating
    The responsibility for calculating and submitting the EEXI rating lies with the vessel owner. The owner must ensure that all necessary data is accurately collected and that the attained EEXI is calculated in compliance with the IMO guidelines. Once calculated, the EEXI rating must be documented and submitted for review and certification as part of the process to obtain the IAPP certificate.

    Meeting the EEXI requirements is crucial for maintaining a valid IAPP certificate, which is essential for legal trading operations. If a vessel does not meet the EEXI standards, the owner must take immediate action to improve the vessel's energy efficiency to ensure compliance. The vessel owner is responsible for the entire process of calculating, documenting, and submitting the EEXI rating to the relevant authorities.

    Common Challenges Faced by the Industry
    - Technical and Financial Constraints: Retrofitting older vessels with energy-efficient technologies can be costly and technically challenging. Smaller shipping companies may struggle to afford the necessary upgrades.
    - Data Collection and Accuracy: Ensuring accurate data collection for EEXI calculation can be complex. Variability in operational conditions can affect the consistency of data.
    - Compliance and Certification: Navigating the regulatory requirements and achieving certification can be time-consuming. Potential delays in certification can disrupt trading operations.
    - Implementation of Power Limitation: Installing and managing power limitation systems may require significant modifications to existing vessels. Balancing power limitations with operational efficiency can be difficult.

    Potential Benefits and Opportunities
    - Environmental Impact: Significant reduction in greenhouse gas emissions, contributing to global efforts to combat climate change. Improved air quality and reduced environmental footprint of the maritime industry.
    - Operational Efficiency: Enhanced fuel efficiency leads to cost savings in fuel expenditure. Improved vessel performance and extended lifespan of engines and equipment.
    - Market Competitiveness: Compliance with EEXI regulations can enhance a company's reputation for sustainability. Access to eco-friendly certifications and potential incentives from ports and regulatory bodies.
    - Technological Innovation: Encourages the development and adoption of innovative energy-efficient technologies. Drives research and collaboration within the maritime industry to find sustainable solutions.

    Future Outlook
    - Stricter Regulations: Anticipate more stringent regulations and standards as part of global efforts to reduce carbon emissions.
    - Technological Advancements: Continued innovation in energy-efficient technologies and practices will further enhance compliance and operational efficiency.
    - Industry Collaboration: Increased collaboration among industry stakeholders to share best practices and develop comprehensive solutions.
    - Sustainability Trends: Growing emphasis on sustainability will drive further investments in green technologies and sustainable shipping practices.

    EEXI related Images (Source: Firefly, Adobe)
  5. The EEXI is a crucial measure introduced by the IMO to enhance the energy efficiency of existing ships and reduce greenhouse gas emissions. Compliance with EEXI regulations is mandatory for ships of 400 gt and above, requiring accurate calculation and certification of the attained EEXI. The implementation of the EEXI is a significant step towards a more sustainable maritime industry. By setting stringent energy efficiency standards, the EEXI promotes the adoption of innovative technologies and operational practices that can substantially reduce the environmental impact of shipping. Compliance with EEXI regulations not only ensures legal trading operations but also positions companies as leaders in sustainability.