Low Sulphur Fuel Oil (LSFO)

Low sulphur fuel oil (LSFO) is residual marine fuel meeting the 0.50 percent m/m sulfur cap of MARPOL Annex VI Regulation 14, in force globally outside emission control areas since 1 January 2020. In practice the dominant 0.50 percent product is VLSFO; ULSFO denotes the 0.10 percent grade used inside ECAs. The 0.50 percent cap cut the prior 3.50 percent limit sevenfold. ISO 8217:2024 added four RM grades for these 0.50 and 0.10 percent fuels in its first full revision since 2017. Ships can meet Regulation 14 by burning compliant LSFO, by an exhaust gas cleaning system (scrubber), or by an alternative fuel such as LNG.