What happens tomorrow? IMO Tier III (NOx) regulations from 2021

In 2021, the IMO Tier III regulations will come into force for all vessels above 24 metres with a combined propulsion power of more than 750 kW and/or generator engines above 129 bkW, and which have had their keel laying after 1 January 2021. The limitations will apply to vessels wishing to sail in the Nitrogen Emission Control Areas (NECAs) North America, US Caribbean, Baltic Sea and the North Sea. For refits, it is important to remember that when an engine is replaced by a new, more powerful one, the IMO Tier IIII certification will also apply.

The regulations initially only covered vessels above 500 GT; however, from 2021 onwards, all vessels will need to comply. This will have a serious impact on our marine industry. For vessels above 500 GT, we have identified several good solutions originating from both engine manufacturers and after-treatment specialists. A major advantage of larger vessels is the fact that they have more available space. This is relevant given that the IMO TIER III (NOx) solutions (SCR) are relatively bulky due to the NOx reduction mechanism and the need to keep backpressure (maximum resistance) of the engine’s exhaust to a certain maximum.

From 2021, SCR after-treatment systems will need to be installed on all vessels, many of which will have much smaller engine rooms. Many yards who are building boats between 24 and 50 metres seem to be unaware of the major impact the new regulations will have on their designs and cost calculations. Most appear to believe that engine manufacturers will have to deliver an IMO Tier III engine, thereby solving the issue for them. Unfortunately, this is not the case: compliance with IMO Tier III regulations will be determined at the level of the vessel itself, not just the engine per se. Moreover, a lot of engine manufacturers are already deploying standard solutions based on land applications and not necessarily adapted for marine use.


Selective Catalytic Reduction (SCR)

Most after-treatment specialists can also assist with delivering a loose SCR with IMO Tier III certification for many engine brands and types. We recommend that you hire a system integrator to check and guarantee that all loose components fit together neatly and jointly satisfy requirements in terms of variables like space, maximum allowable backpressure, noise reduction and suitability for marine use.

So, are you ready for 2021? Choosing the right engine in combination with the smallest and most flexible after-treatment system will certainly place you at the cutting edge of engine room layout. And smaller engine rooms free up room on a boat for accommodation space, which is good for everyone.

If you require help or guidance of any kind, do not hesitate to turn to us. We are here for all your questions and needs.


MarQuip BV
Jeroen van der Matten
General Manager Operations

www.marquip.nl