New article by Ådland and Jia

9 January 2018 14:42

New article by Ådland and Jia

The article "The energy efficiency effects of periodic ship hull cleaning" has been published in Journal of Cleaner Production.

Ådland, Roar Os, Pierre Cariou, Haiying Jia, and Francois-Charles Wolff: The energy efficiency effects of periodic ship hull cleaning, Journal of Cleaner Production, 2018, 178, 1-13, Online 04.01.2018.


This paper investigates the impact of periodic hull cleaning on oil tankers' energy efficiency using real 2012–2016 fleet performance and weather data extracted from noon reports for a fleet of eight identical Aframax-size crude oil tankers. The impact of changes in fuel consumption is estimated around the discontinuity when a vessel is cleaned and rely on both before-after and difference-in-differences estimators.

The main results show that (i) periodic hull cleaning leads to a significant reduction in the daily fuel consumption; (ii) dry-docking leads to greater and significantly different reductions in fuel consumption than underwater hull cleaning, approximately −17% versus −9%; (iii) hull cleaning energy efficiency effect is greater when the vessel is sailing laden rather than in the ballast condition. These findings represent a key building block for the optimization of maintenance intervals.