A Comparative presentation of CII and EEXI Energy Efficiency Indicators

Integrating real-time data and performance analysis of individual ships with weather routing services allows Artificial Intelligence to deliver a huge leap forward for voyage optimization

By Andreas Symeonidis,
Marketing & Partner Relations Manager at METIS Cyberspace Technology
Andreas Symeonidis

As part of its regulatory framework, the IMO has introduced energy efficiency measures, which include two key indicators: the Carbon Intensity Indicator (CII) and the Energy Efficiency Existing Ship Index (EEXI). In this article, we will explore and compare these two indicators in relation to IMO regulations and their impact on the shipping industry.

IMO Strategy

Carbon Intensity Indicator (CII):
The CII is a regulatory tool developed by the IMO to assess and measure the amount of carbon dioxide (CO2) emitted per transport work. It provides a standardized approach for monitoring and reporting the energy efficiency of ships. The CII focuses on operational efficiency and aims to encourage shipowners and operators to improve their vessels’ performance. By calculating the ratio of CO2 emissions to the transport work, the CII sets a benchmark for reducing emissions and achieving greater energy efficiency.

IMO – CII Rating Infographic

Energy Efficiency Existing Ship Index (EEXI):
The EEXI is another energy efficiency indicator introduced by the IMO. It measures the energy efficiency of existing ships and determines the required technical measures to reduce emissions. The EEXI takes into account the ship’s design efficiency and compares it with a reference line based on the vessel’s size and type. If a ship’s EEXI exceeds the required limit, the shipowner must undertake modifications to enhance energy efficiency.

IMO – EEXI Infographic

Comparison of CII and EEXI:

a. Scope and Applicability: The CII focuses on operational efficiency and applies to all ships of 5,000 gross tonnage and above. It accounts for the transport work, which considers factors such as distance traveled, cargo carried, and fuel consumption. On the other hand, the EEXI is primarily concerned with the design efficiency of existing ships. It applies to vessels of 400 gross tonnage and above, and its purpose is to ensure that ships meet certain energy efficiency requirements.

b. Assessment Methodology: The CII calculates carbon intensity by dividing CO2 emissions by the transport work. It establishes an intensity value in grams of CO2 per tonne-mile. The EEXI, however, evaluates a ship’s energy efficiency by comparing its design efficiency with a baseline value. The baseline varies depending on the ship’s size, type, and construction date. The EEXI is expressed as a numerical value representing the ship’s energy efficiency index.

c. Compliance and Implementation: For ships subject to the CII, the IMO requires the submission of annual reports detailing the ship’s energy efficiency and emissions data. Compliance is measured against the required CII value, and continuous improvement is encouraged. In the case of the EEXI, ships that do not meet the energy efficiency standards must implement technical measures to enhance their performance. Compliance with the EEXI is assessed during the vessel’s survey and certification process.

Both the Carbon Intensity Indicator (CII) and the Energy Efficiency Existing Ship Index (EEXI) play crucial roles in reducing greenhouse gas emissions and promoting energy efficiency in the shipping industry. While the CII focuses on operational efficiency, the EEXI emphasizes the design efficiency of existing ships. These indicators, along with other IMO regulations, aim to drive significant improvements in the industry’s environmental performance. METIS offers functionality and KPIs that enable accurate measurement of the CII, detailed documentation about the factors that affect the CII, visualization of the future trend and quantification of the benefit on corrective actions. METIS helps shipping companies to meet regulatory requirements and contribute to a sustainable future for maritime transportation while retaining the commercial value of their assets.

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