Marine Fuel Glossary

VLSFO — very low sulphur fuel oil, maximum 0.50% sulphur, the default global marine fuel since 2020.

HSFO — high sulphur fuel oil, typically 3.50% sulphur, usable only by vessels fitted with exhaust gas cleaning systems.

MGO and ULSFO — marine gasoil and ultra low sulphur fuel oil (0.10% sulphur), used inside emission control areas.

Bio-blends and LNG — B24 and similar biofuel blends, plus LNG, methanol and ammonia as emerging bunker fuels.

Stem — the agreed quantity of fuel to be delivered for a specific vessel call.

Bunker barge — the delivery vessel that transfers fuel ship-to-ship at anchorage or berth.

Bunker Delivery Note — the document recording quantity, grade and sulphur content at delivery.

Mass flow meter — metering equipment mandated in some hubs to verify delivered quantity.

IMO 2020 — the global 0.50% sulphur cap on marine fuel.

ECA — emission control area, where a 0.10% sulphur limit applies.

CII and EEXI — operational carbon intensity and energy efficiency indicators applied to existing vessels.

EU ETS and FuelEU Maritime — European carbon pricing and fuel intensity rules affecting voyage costs.

Scrubber spread — the VLSFO minus HSFO price difference that determines scrubber payback.

Delivered versus ex-wharf — pricing including barge delivery versus collection at the terminal.

Credit line — the supplier facility that determines how much fuel a buyer can lift before payment.