Scrubbers: Closing the loop; Activity 3. Task 4; Evaluation of exhaust gas scrubber systems for ship applications in a system perspective.
In this study different options to comply with the regulations on sulphur emissions from ships are studied using life cycle assessment (LCA) methodology. Environmental impacts from a ship operating on heavy fuel oil in combination with exhaust gas cleaning systems, so called scrubbers, are compared with those from operations on low sulphur fuel oil (LSFO). Two alternative production ways for LSFO were investigated. The quantitative analysis is foremost a comparison of effects relating to the energy need and the effects of removing sulphur in a refinery compared to removal in the exhaust gases on the ship. The internal order of the compared options’ performances in the impact categories varies. Overall, the life cycle assessment indicated only minor differences between the studied compliance alternatives in all impact categories. The LSFO produced in a hydrocracking process were the most energy demanding of the compared alternatives. This was reflected in the calculated global warming potential of the system but not in the impact categories eutrophication potential and acidification potential. An LSFO produced similarly to marine gasoil has less life cycle emissions to air than the other alternatives.