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A comparison of NOx mitigating technologies for ships using fleet-wide continuous emissions monitoring

Lookup NU author(s): Fengshuo Xing, Dr Kayvan Pazouki, Dr Alan J Murphy, Dr Rosemary NormanORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Maritime transport is the backbone of domestic and international trade and economy. Around 80% of global trade by volume and over 70 % by value are carried by sea. The global proportion of NOx emissions from shipping is estimated at around 15 %. One of the key aspects to reduce emissions is to use mitigating technologies, however these technologies can only be effectively deployed, and system design decisions made, if their actual performance in real operational settings is known. This paper investigates the effectiveness of several NOx emissions mitigating technologies, applying them on 10 older inland waterway vessels. These measures include primary and secondary measures applied at and after the engine, respectively and the use of alternative fuels. The real-world NOx emissions and other engine operational parameters were recorded using continuous monitoring systems over extensive time periods (>1 year). The data were analysed to generate specific load-dependent NOx emission factors for each technology which were then generalised using averages with weighting functions that are relevant to those used in EU regulations. The emission factors are used to determine the effectiveness of each of the mitigating technologies under different operating conditions and their relative performance is compared. This paper considers the detail and challenges of monitoring ship emissions at fleet-scale over long periods of time and considers the relative performance of the NOx mitigating technologies that the analysis revealed.

Publication metadata

Author(s): Xing F, Pazouki K, Murphy AJ, Norman R

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: 15th International Symposium on Practical Design of Ships and Other Floating Structures PRADS 2022 Dubrovnik, Croatia,

Year of Conference: 2022

Pages: 12

Online publication date: 12/10/2022

Acceptance date: 19/07/2022

Date deposited: 03/08/2023


ePrints DOI: 10.57711/2abj-9527

Notes: Page 12 of the programme - 24. technical Sessions Wednesday 12/10/22 09:00-10:40