High sulphur fuel oil (HSFO)
The ISO 8217:2024 Table 4 product, who buys it, its tie to exhaust gas cleaning, and the demand recovery visible in the Singapore bunker series.
High sulphur fuel oil is residual marine fuel with a sulphur content above 0.50 percent by mass. In ISO 8217:2024 it is Table 4, carrying the grades RME 180H, RMG 180H, RMG 380H, RMK 500H and RMK 700H, where the H suffix marks high sulphur. Clause 10.5 states in terms that Table 4 fuels are for use on ships in conjunction with approved equivalent alternative abatement technologies such as exhaust gas cleaning systems.
That sentence explains the whole market. Since 1 January 2020 the MARPOL Annex VI global limit has been 0.50 percent, so HSFO is lawful as fuel only for a ship operating an approved equivalent under regulation 4. Its buyers are therefore scrubber-fitted ships, and its demand tracks scrubber installation rather than the fuel’s own merits.
The recovery in that demand is the most striking commercial fact in marine fuels. Singapore’s high sulphur fuel oil sales fell 73 percent in a single year, from 38.10 million tonnes in 2019 to 10.65 million tonnes in 2020, then rose in every one of the following five years to 22.09 million tonnes in 2025, which is 38.9 percent of the port’s sales and more than double the trough. The full article will cover the Table 4 specification, the scrubber tie, the scrubber spread as the economic variable, and the regulatory risk a high sulphur position carries.