Investigating a conventional and retrofit power plant on-board a Roll-on/Roll-off cargo ship from a sustainability perspective - A life cycle assessment case study

Following the enforcement of MARPOL Annex VI Regulations for the Prevention of Air Pollution from Ships, retrofitting conventional power plants with emerging technologies is seen as a means to promote sustainability of marine transport and comply with more stringent emissions legislation. However, a knowledge gap exists as the environmental performance of retrofit power plant solutions incorporating emerging technologies has not been examined using an integrated system approach based on Life Cycle Assessment. The purpose of this research was to investigate if integrating selected emerging technologies i.e. photovoltaic systems, lithium-ion batteries, cold ironing and power-take-off/power-take-in systems supplemented by frequency converters and variable frequency drives into an existing power plant would be to the advantage of a chosen ship type i.e. Roll-on/Roll-off cargo ships, from the perspectives of resource consumption and environmental burden. Using the power plant of an existing vessel as a case study, it was found that cast iron, steel, copper and aluminium were the four materials most commonly consumed during manufacturing phase i.e. 2.9 × 105 kg, 1.9 × 105 kg, 5.3 × 104 kg and 2.9 × 104 kg respectively. By burning 2.9 × 107 kg of heavy fuel oil and 2.3 × 108 kg of marine diesel oil during operation, 8.2 × 108 kg of carbon dioxide, 1.7 × 107 kg of nitrogen oxides, 6.1 × 106 kg of sulphur dioxide, 7.6 × 105 kg of carbon monoxide, 6.5 × 105 kg of hydrocarbon and 4.7 × 105 kg of particulate matter would be released. Over a projected 30-year period, emissions released to air and freshwater were found to be significant. Based on 3 characterisation methodologies, ecotoxicity potential, with 7-10 orders of magnitude, was identified as the most significant environmental burden. Consuming and storing resources had the least impact, operating diesel engines and auxiliary generators had a moderate impact, and disposing metallic waste had the highest impact. The research concluded that the environmental burden caused by a marine power plant was significant but retrofitting existing power plant with suitable emerging technologies could reduce a number of impacts by 4-7 orders of magnitude, as verified via scenario analysis. However, the system should be designed and managed with due care as the environmental benefits, such as lower fuel consumption, emission reduction and performance improvement in some environmental measures are always achieved at the expense of an increase in other detrimental impacts.