Analysing ship emissions under complex operating conditions: Insights from onboard measurement data

Area of Science:

• Marine Engineering
• Environmental Science
• Naval Architecture

Background:

• Older vessels contribute significantly to maritime emissions.
• Understanding ship operational emissions is vital for environmental regulations.
• Low-load operations are common but often underrepresented in studies.

Purpose of the Study:

• To evaluate the emission characteristics of older ships during various operational phases.
• To identify emission hotspots during typical voyages, cruising, and lock transits.
• To provide data supporting maritime decarbonization efforts.

Main Methods:

• Utilized a shaft power meter and Portable Emissions Measurement Systems (PEMS).
• Monitored emissions during typical operations, varying speeds, and lock transits.
• Analyzed emission factors for CO, NO_X, CO₂, and SO₂.

Main Results:

• Low-load voyages constituted over 65% of total voyage time.
• Highest average emission factors for CO, NO_X, and CO₂ occurred during lock transit.
• SO₂ emissions peaked during maneuvering; emissions correlated with engine speed.

Conclusions:

• Lock transit and maneuvering are critical phases for high emissions in older ships.
• Current engine test cycles should incorporate low-load conditions.
• Findings support targeted strategies for maritime emission reduction and decarbonization.