Scheduling of Power Generations for Energy Saving in Hybrid AC/DC Shipboard Microgrids

Trending in the maritime industry nowadays, is towards an energy efficient and fuel saving. Moreover, concerns regarding global warming issues caused by massive air pollution in sea area by the ship combustion engine and depletion of fossil fuels have attracted attention and opportunities for many parties. The electric propulsion has been used in ship for many years. It has triggered the concept of all electric ship where all electrical equipment including electric propulsion, connected to the electrical networks to achieve better fuel consumption with less emission. However, the main generation in the ship is still diesel generators. Connecting more generator in parallel is normal practice to cater the load. However, due to the nature of non-linear characteristic in thermal unit, such as diesel generator, based on specific fuel consumption (SFC) curve, the generator loading is not efficient when running the generator with low load factor or higher SFC. Thus, the effective energy scheduling is needed among the generators so that the generators is operated in optimum point. The case study in this paper is ferry, with a conversion from traditional diesel mechanical power to electric propulsion powered by diesel generator as a main source and energy storage as secondary source. This paper analyzes how much the operating cost of the scheduled system implemented in this practical electric ferry based on an estimation of SFC curve considering the dynamic load profile.