How Kpler Determines CII
Kpler estimates the Carbon Intensity Indicator (CII) for vessels using two main sources of data: Automatic Identification System (AIS) data for distance traveled and an emissions model for fuel consumption.
Distance Traveled: We use AIS data, which tracks the vessel's journey, to calculate the total distance traveled. This data includes the ship's location, speed, and navigational status.
Fuel Consumption: Our emissions models take into account vessel specifics (like size and type) and engine details to estimate fuel use for both main and auxiliary engines across different operational modes.
The estimated CII is calculated by dividing the estimated annual CO2 emissions (from fuel consumption) by the product of the vessel's deadweight and the distance it has traveled. It's important to note that these CII values are estimates, not verified data from the IMO Data Collection System (DCS). While our method provides valuable insights for improving environmental performance, official CII ratings for compliance purposes come from the IMO DCS, based on reported and verified data.
Current Year (YTD) CII vs. Past Years' CII
Explaining the distinction between the Carbon Intensity Indicator (CII) for the current year, known as Year-To-Date (YTD) CII, and the CII for past years is important.
Current Year Attained CII (YTD CII)
Data Basis: The YTD CII (and CII rating) relies on real-time data, incorporating the cumulative distance traveled and estimated CO2 emissions as they are reported on our platform. This ensures that the CII reflects the vessel's operational performance throughout the current year.
Update Frequency: We update our emissions data weekly, capturing emissions from ongoing voyages. This regular update schedule means that the YTD CII is a near-real-time representation of a vessel's carbon intensity, allowing our users to get access to the most up-to-date data.
Past Years' CII
Data Basis: The CII for past years is calculated from the complete set of data for each year, including the total distance traveled and total estimated CO2 emissions. This historical CII provides a fixed benchmark of a vessel's environmental performance for that year.
Historical Data Updates: It's important to note that while past years' CII values are based on historical records, these records may be occasionally be updated. This is due to improvements in our emissions model and further calibration using primary data, ensuring that past CII values remain as accurate and relevant as possible despite being historical.
Understanding operational efficiency calculation methodology - CII rating
CII is an operational index derived from Annual Efficiency Ratio (AER) which measures the total carbon emissions from all laden voyages, ballast voyages, port stays and idle periods, divided by the deadweight and distance travelled in a year. CII indicates how efficiently a ship operates and is expressed as "grams of CO2 per DWT nautical mile". Rather than looking at actual cargo carried, CII assumes that each vessel is always loaded to the maximum cargo carrying capacity, hence a constant value.
Based on a ship's CII, IMO regulates that the carbon intensity will be assigned the following ratings based on the ships' performance level:
A - major superior (best)
B - minor superior
C - moderate a.k.a. required CII level
D - minor inferior
E - inferior (worst)
The boundaries are determined by the required annual operational CII in conjunction with the vectors (d1, d2, d3 and d4) that indicates the direction and distance deviations from the required CII value. As IMO aimed at cutting the carbon intensity of all ships - new build and existing ships - by at least 40% by 2030, compared to the 2008 baseline, the criteria of CII ratings will be progressively tightened each year in order to motivate ship operators to continuously optimise and pursue better operational efficiency.
The actual annual operational CII achieved must be documented and verified against the required annual operational CII. The performance level will be recorded in a "Statement of Compliance" to be further elaborated in the ship's Ship Energy Efficiency Management Plan (SEEMP).
Corrective action plan submission is required to demonstrate how the rating of C (or better) will be achieved for ships rated as D for three consecutive years, or E for one year.
Administrations, port authorities and other stakeholders as appropriate, are encouraged to provide incentives to ships rated as A or B.
For more information regarding the methodology stipulated by IMO, please download the revised MARPOL Annex VI (2021 Revised MARPOL Annex VI) and related guidelines via this page: Index-of-MEPC-Resolutions-and-Guidelines-related-to-MARPOL-Annex-VI