Abstract
For the maritime sector to be sustainable and to have an intact blue economy, shipowners should be ready to implement Ship Energy Efficiency Management Plans alongside energy efficiency projects. The problem for organizations and shipowners having fishing carriers older than 20 years is highlighted and the following challenges arise for decision-making authorities. To keep such ships in the fleet for the next decade, shipowners should deploy energy efficiency projects for marine system retrofitting to improve energy efficiency and meet environmental regulations. An energy audit is performed and an energy efficiency program is proposed with guidelines for regulations that are currently coming into force. To improve energy efficiency, reduce the environmental impact, and cut fuel consumption costs, marine system retrofitting is done, in a particular case, with two options proposed. The first is a cascade refrigeration system with hydrocarbons and carbon dioxide, where the shipowner gains an energy efficiency improvement of about 20%. The second option is a two-stage refrigeration system with ammonium as the environmentally friendly refrigerant, which improves the energy efficiency by about 26%. Technical and economic issues have been discussed.