A Rulebook That’s Simple on Paper
Under MARPOL Annex VI, the sulphur oxide (SOx) limit for ships operating outside Emission Control Areas is 0.50% m/m. Many vessels have met this requirement by installing Exhaust Gas Cleaning Systems (EGCS). An expensive, complex machinery designed to allow continued use of high sulphur fuel oil (HSFO) while remaining compliant.
On paper, it sounds straightforward: fit an EGCS, burn HSFO, stay within limits. At sea, the reality is far more complicated.
At sea, it is not that clean.
EGCS is not just an emissions device. It is another operating condition the ship must manage across changing port rules, fuel requirements, engineering limits, and documentation pressure.
Local Rules, Global Confusion
The difficulty begins when local port regulations override what IMO rules otherwise allow.
In Fujairah and Oman, EGCS use is prohibited, forcing ships to change over to VLSFO or MGO before arrival. In Oman, proximity to territorial limits can require the switch even earlier. Inside the Persian Gulf, EGCS operation and washwater discharge may be permitted, until the next port changes the operating condition again.
For the ship, this creates a moving compliance target.
The same system that is accepted in one area may become unusable at the next port. The vessel remains technically equipped for compliance, but the crew still has to manage fuel changeover, documentation, timing, machinery limits, and the risk of getting the local interpretation wrong.
The Engineer’s Burden
The engineering burden does not remain hidden below deck. From the bridge, it is visible in timing, speed planning, port approach preparation, fuel readiness, and compliance documentation.
Fuel changeover is not a simple switch. It involves isolating and re-routing fuel lines, adjusting fuel temperatures gradually, monitoring purifier performance, checking compatibility, and avoiding filter clogging or asphaltene precipitation. During these transitions, fuel pump seal leakage remains a real risk, especially when viscosity and lubrication properties change abruptly. A sudden drop in viscosity can reduce the hydrodynamic film in pump plungers and seals, increasing wear and the chance of leakage.
Every changeover also creates a documentation trail. The ship must prove not only that it complied, but that it complied at the correct time, in the correct area, using the correct fuel and operating mode.
That is the real burden. The regulation may sit in MARPOL Annex VI, but the workload lands on the ship.
Decisions Made from Shore
From the bridge, the logic of these restrictions often appears inconsistent. Ports in open waters ban EGCS discharge, yet enclosed waters allow it.
Too often, such regulations are introduced without transparent scientific studies or operational impact assessments. Some are decided by authorities with limited maritime operational experience, leading to rules that may satisfy political optics but impose disproportionate technical and safety burdens on ships.
A Structural Problem at the Core
The larger issue is systemic. The IMO can regulate ships, but it cannot by itself create one global fuel supply reality across ports, terminals, bunker suppliers, and coastal states.
Instead of solving the problem upstream, the compliance burden lands downstream on the vessel. Ships install expensive equipment, carry multiple fuel strategies, manage local restrictions, and still face port-by-port uncertainty over whether the system may actually be used.
That is the contradiction at the heart of EGCS. The ship pays for the hardware, but permission to use it remains conditional.
The Real-World Consequences
- Financial Inefficiency: HSFO–VLSFO price advantage disappears where bans exist.
- Operational Risk: More fuel changeovers mean more chances of machinery problems, timing errors, and documentation gaps.
- Science vs Politics: Many bans lack published local environmental data.
- Crew Fatigue & Human Error: More changeovers mean higher risk of mistakes or machinery issues.
- No Unified Enforcement: Many restrictions are introduced without clearly published local environmental data.
The Question That Won’t Go Away
Where is the environmental gain? Frequent fuel switching, additional CO₂ from extra operations, and politically driven bans without scientific backing risk undermining MARPOL’s intent.
Until there is a single global standard for both fuel supply and EGCS acceptance, the industry will keep pouring money into systems it is not always allowed to use, forcing crews into unnecessary risks and inefficiencies.
The current regime may tick the compliance box, but it leaves ships, seafarers, and ironically the environment short-changed.
Media Section
Sources
IMO 2020 sulphur limit.
IMO MEPC.340(77) EGCS Guidelines.
ClassNK regional EGCS restriction list.
Port of Fujairah open-loop scrubber restriction.
Leave a Reply