Carbon intensity (CI) expresses greenhouse gas emissions per unit of energy, usually in grams of CO₂ equivalent per megajoule (gCO₂e/MJ). A CI number is comparable only when the lifecycle boundary, gases, global-warming potentials, calorific-value basis, and calculation method are also comparable. It is not a complete sustainability score.
The International Maritime Organization's 2024 lifecycle guidelines separate well-to-tank emissions from tank-to-wake emissions and combine them for a well-to-wake result. Feedstock, production energy, transport, fuel pathway, and onboard conversion can all affect that result. A fuel name alone therefore does not establish its lifecycle CI.
FuelEU Maritime uses a defined well-to-wake method for the yearly average GHG intensity of energy used on board an in-scope ship. Its reference value is 91.16 gCO₂e/MJ, reduced by 2% for 2025 through 2029, which is 89.34 gCO₂e/MJ when rounded to two decimals. The EU ETS is a separate system: a shipping company surrenders allowances for reported emissions that fall within ETS scope. It does not calculate that obligation directly from a quoted lifecycle CI value.
For procurement, ask which boundary and method produced the number, whether the value is a default or an actual value, which evidence supports the feedstock and pathway, who verified it, and for what period it is valid. Also check that the energy basis and units match before comparing offers.
Verdaxis records supplier-declared CI on executable ASK listings and records a declared lifecycle method for B30 and B100 listings. These fields help buyers compare declarations. Verdaxis does not independently verify supplier certificates or the declared CI, so buyers must review the supporting documents and the rules that apply to their use case.