CII Fuel Mix Correction

Quantify how a multi-fuel bunker mix (LNG, methanol, ammonia, biofuel blends, drop-in replacements) changes the attained CII relative to a baseline single-fuel reference. The principal tool for evaluating CII benefit of fuel switching, biofuel pilot purchases and dual-fuel operation under MEPC.336(76).

CIIFuel mixMEPC.336(76)MEPC.364(79) Cf

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This calculator requires JavaScript to compute its result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

\text{CII}_\text{baseline} = \frac{F_\text{base} \cdot C_{f,\text{base}} \cdot 10^6}{\text{Capacity} \cdot D}

Symbol	Meaning	Unit
$\text{CII}_\text{baseline}$	Attained CII if 100% baseline fuel were burned	g CO₂/(cap·nm)
$\text{CII}_\text{actual}$	Attained CII for the actual mix	g CO₂/(cap·nm)
$F_\text{base}$	Mass of baseline fuel (energy-equivalent)	t
$F_j$	Mass of fuel $j$ in the actual mix	t
$C_{f,\text{base}}$ , $C_{f,j}$	Tank-to-wake CO₂ conversion factor	t CO₂/t fuel
$\text{LCV}_\text{base}$ , $\text{LCV}_j$	Lower calorific value	MJ/kg
$E_\text{total}$	Total bunker energy	MJ
$s_j$	Energy share of fuel $j$ in the mix	fraction
$Capacity$	DWT (cargo) or GT (ro-pax / cruise)	t or -
$D$	Distance travelled in the reporting year	nm

Source: IMO Resolution [MEPC.336(76)](https://www.imo.org) - 2021 Guidelines on operational CII; IMO Resolution [MEPC.337(76)](https://www.imo.org) - Reference lines; IMO Resolution [MEPC.338(76)](https://www.imo.org) - Reduction factors; IMO Resolution [MEPC.339(76)](https://www.imo.org) - Rating boundaries; IMO Resolution [MEPC.364(79)](https://www.imo.org) - Cf factors

In short

Quantify how a multi-fuel bunker mix changes attained CII relative to a single-fuel baseline. Covers LNG, methanol, ammonia, biofuel blends and dual-fuel operation under MEPC.336(76) and MEPC.364(79).

Learn the theory BIMCO CII and Emissions Clauses