Scheduling of Power Generation in Hybrid Shipboard Microgrids with Energy Storage Systems

Concerns about the impact of global warming caused by air pollution and depletion of fossil fuels have attracted attention and opportunities in transportation especially in maritime industry. In all electric ships, the electrical equipment including electric propulsion is connected to the common ship electrical network to achieve better fuel consumption with less emission. However, the low-load factor of the parallel diesel generators (DGs) in some operating conditions, can negatively affect the fuel consumption rate. As an alternative, two or more power sources such as batteries and renewable-based prime movers can be integrated into the system aboard to improve the overall system performance. By optimal scheduling of the power sources, poor low-load efficiency can be avoided and controllable units can be dispatched in an emission-aware and cost-effective manner. This paper analyzes how much the operating cost of a shipboard system can be improved (based on estimation of specific fuel consumption (SFC) curve of a real system) considering the dynamic load profile with and without energy storage systems (ESSs). The case study in this paper is a ferry with a conversion from traditional diesel mechanical power to electrical propulsion powered by DGs and ESSs.