The Ultra Low Emission Vessel (ULEV)


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The pursuit of sustainable practices in the shipping industry has led to a concerted effort to minimize emissions from large engine operations. This drive has given rise to the concept of Ultra Low Emission Vessels (ULEVs), which exceed existing emission standards and embrace cutting-edge technologies to ensure a cleaner maritime future.

In the shipping industry, zero emissions for large engine operation is a long-term target. To reach this target, advances in the technical field need to be made, such as fuels, engines, and exhaust gas after-treatment systems (Daniel Peitz, 2020).

What is ULEV?

Today, seagoing vessels need to conform to the IMO Tier II emission requirements and IMO Tier III emission requirements while operating in ECAs (International Maritime Organization, sd). Within the emission requirements for Tier II and Tier III, the IMO restricts only the Nitrogen Oxides and Sulphur Oxides emissions, while carbon monoxide (CO), hydrocarbons (HC), particulate matter on mass (PM), or number (PN) basis are not considered.

Therefore, the ULEV (Ultra Low Emission Vessel) notation has been developed. ULEV is a voluntary notation that goes beyond the existing IMO Tier III emission requirements. By considering the above-mentioned emission components, ULEV adapts the EU Stage V emission requirements.

These requirements are already mandated for non-road mobile machinery in the European Union. The ULEV notation prepares vessels to comply with upcoming national and international environmental legislation by limiting the harmful pollutant emissions from the engine(s) (Bureau Veritas, 2023).

How to acquire ULEV notation?

The ULEV notation is developed by Bureau Veritas to enable ship owners to distinguish their fleet by demonstrating their commitment to environmental protection and performance. The certification process entails demonstrating the low emissions on a testbench and providing all the accompanying documentation.

A ULEV vessel contains an engine with a specialized exhaust gas after-treatment system. For the system to receive the ULEV notation, the engine requires an EIAPP certificate. This certificate indicates that the pre-certification survey shows that the engine, its components, adjustable features, and Technical File, prior to the engine’s installation and/or service on board a vessel, fully comply with the applicable regulation 13 of Annex VI of MARPOL (Navsregs, 2017).

The ULEV notation additionally requires the specialized exhaust gas after-treatment system. This system consists of the SCR system and the DPF system. The SCR system reduces the NOX component in the exhaust gases, while the DPF system removes solids from the exhaust gases.

Checks and surveys

When all the relevant information is submitted to the classification society inside the Technical File, as required by regulation 13 of Annex VI of MARPOL, the engine with exhaust gas after-treatment system is subject to a conformity check to ensure compliance with emission limits. The conformity check is conducted with a surveyor on the testbench. Finally, the engine needs to be surveyed during an onboard inspection to ensure compliance with relevant documentation and installation instructions.


  • IMO – International Maritime Organization
  • ECA – Emission Control Area
  • EIAPP – Engine International Air Pollution Prevention
  • MARPOL – International Convention for the Prevention of Pollution from Ships
  • SCR – Selective Catalytic Reduction
  • DPF – Diesel Particulate Filter


About the author

Jelle Westerhof is sales manager at Emigreen® and applies our industry-leading solutions to the projects of our clients. Feel free to reach out to Jelle for feedback on this article, for questions and for a free consultation.