Optimum sizing of energy storage for an electric ferry ship

Abstract

Each vessel has a different load profile based on its application. Among the vessels, the ones that have electrical propulsion systems with high fluctuations of propulsion demand power incur poor fuel consumption efficiencies due to: a) low loading of the generators and the lower efficiency in lower loads, and b) variations in the output power of the generators. Therefore, it may be economically feasible to install energy storage units in such ships to improve generator efficiencies.Given the load profile of a vessel, this paper formulates a simple but general deterministic dynamic optimization problem to find the optimal loading strategy for the ship generators in the presence of an energy storage unit. It then adds an outer layer to the optimization problem that finds the optimum capacity for the energy storage.

Optimal Sizing of Energy Storage Systems for Shipboard Applications

“…P g enmin ≤ P g enij ≤ P g enmax (24) SoC m a x − DoD m a x ≤ SoC i j ≤ SoC m a x (25) Finally, this formulation allows to set the initial state of some variables, which are defined as inputs. These, are the initial state u i , 0 for the DGs in equation (26) and the initial state of charge SoC 0 of the storage system in equation (27).…”

“…Nevertheless, aging effects on ESS depending on its management and the resulting optimal sizing are topics not covered in this work. On the other hand, the optimal ESS size selection depending on the management strategy is studied in [26]. In fact, authors formulate a dynamic dispatch problem (DDP) to find the optimal loading strategy for DGs and ESS, validating the method on a case study.…”

Review of Ship Microgrids: System Architectures, Storage Technologies and Power Quality Aspects

“…In contrast, the power sources include diesel generator and gas turbine engines [24,25]. Medium power applications such as electric ferry ships may involve the power generation capacities in the order of 10 MW, e.g., 12 MVA system in [26]. Such examples demonstrate that the maritime power requirements significantly vary depending on the functionality of the ship.…”

A cost-effective and emission-aware power management system for ships with integrated full electric propulsion

“…Optimal power generation scheduling combined with demand side management will result in several positive effects in ship design and operation; like the reduction of the number of the prime movers, further fuel cost reduction, efficient limitation of GHG emissions etc. Some other measures that are examined in the related literature to improve ship power system efficiency are listed in the following: energy management and vessel performance [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], route optimization and voyage efficiency [22,23], slow-steaming (reduction of ship cruising speed) [28], effective demand side/load management [11,18,19,23], means of smart electric energy generation [16,25], cold ironing [17,22], and electric energy saving devices and energy storage systems (ESS) [19,20,23].…”