The Carbon Intensity Indicator measures how efficiently a ship transports cargo relative to its CO₂ emissions. Mandatory since 2023, with tightening targets each year.
The Carbon Intensity Indicator (CII) is part of IMO's MEPC 76 regulations requiring ships of 5,000 GT and above to calculate and report their annual operational carbon intensity. Ships receive a rating from A (best) to E (worst) based on their attained CII vs required CII.
The calculation uses the AER (Annual Efficiency Ratio) methodology:
Sum all fuel consumed during the year by type (VLSFO, HSFO, LSMGO, MGO) from voyage records and noon reports.
Multiply each fuel type by its IMO emission factor. VLSFO: 3.151 t-CO₂/t-fuel. HSFO: 3.114. LSMGO: 3.206. MGO: 3.206.
Total nautical miles sailed multiplied by the vessel's deadweight tonnage. This represents transport work capacity.
Attained CII = CO₂ / (DWT × Distance). Compare against the required CII for your ship type and size. The ratio determines your A-E rating.
Ship must develop a corrective action plan within the SEEMP (Ship Energy Efficiency Management Plan). The plan must describe how the ship will achieve at least a C rating. Class society reviews the plan.
Same as D, plus enhanced surveys and potential operational restrictions. Three consecutive years of D or E triggers mandatory review. Charterers and cargo owners increasingly refuse D/E vessels.
The most effective lever. Fuel consumption scales with speed cubed — a 1 knot reduction on a Supramax saves approximately 15-20% fuel and proportionally improves CII.
Bio-fouling increases fuel consumption by 10-30%. Regular hull cleaning and propeller polishing can improve CII by 5-15%. TRIVOYA's hull fouling detection tells you when it's time.
Weather routing, optimal trim, ballast management, and port efficiency all contribute. TRIVOYA's voyage planning calculates fuel consumption at different speeds so you can make informed tradeoffs.
Higher quality fuel burns more efficiently. TRIVOYA's quality-performance correlation analysis shows the direct link between fuel quality scores and consumption rates per vessel.
No. EEDI (Energy Efficiency Design Index) applies to new-build ships and measures design efficiency. EEXI (Energy Efficiency Existing Ship Index) is a one-time technical measure for existing ships. CII is an operational measure calculated annually from actual fuel consumption and distance sailed. A vessel can have a good EEXI but a poor CII if it operates inefficiently.
Yes, and they increasingly do. Major charterers including Cargill, Trafigura, and Rio Tinto are incorporating CII ratings into their vessel vetting criteria. D and E rated vessels face charter rate discounts of $500-2,000/day. Some charterers refuse D/E vessels entirely. Banks are also linking financing terms to CII performance.
Fuel consumption scales approximately with the cube of speed. For a typical Supramax at 13 knots, reducing to 12 knots saves roughly 18% fuel consumption and proportionally improves CII. The trade-off is 8% longer voyage time. TRIVOYA’s voyage planning tool calculates the exact fuel savings and CII impact for each speed option.
IMO has set annual CII reduction factors that tighten each year. The 2023 baseline requires approximately 5% improvement by 2026. A comprehensive review of the CII framework is scheduled for 2026, where IMO will assess whether to maintain, strengthen, or modify the current trajectory. Most industry analysts expect tightening.
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