# Developments, Trends, and Challenges in Optimization of Ship Energy Systems
## Appendix A Main Characteristics of Journal Articles on Optimization of Ship Energy Systems
(2019) [PERSON]; [PERSON]; [PERSON] _Energy_**2019**. System: two diesel-generator sets and one battery pack in all-electric short-haul ferry. Operation optimization. Four operating states during a round trip of 60-100 min. Objective function: minimization of the operating cost, as expressed by minimization of fuel consumption. Independent variables: power output of each DG set and charging power of the battery pack. Algorithm: hybrid of Grey Wolf Optimizer and Fuzzy Logic expert system. GWO determines the power output of each DG set, while FL determines the charging power of the battery pack. Iteration between GWO and FL is performed until convergence. * [PERSON] and [PERSON] (2019) [PERSON]; [PERSON] _Journal of Energy Storage_**2019**. System: battery for electricity storage operating with diesel or gas generators in all-electric ship. Design and operation optimization in terms of battery choice, sizing, and energy flows management among the different energy units. A load profile is considered (hour, day, week, etc.) that is repeated throughout the typical year. Objective function: minimize total cost (investment + operation). Algorithm: Mixed Integer Linear Programming. * [PERSON] et al. (2019) [PERSON]; [PERSON]; [PERSON] _Journal of Operation and Automation in Power Engineering_**2019**. System: HESS-hybrid power system with energy storage (ESS), photovoltaics (PV), and diesel generator in oil tanker. The stochastic character of solar radiation is taken into consideration. Design optimization (sizing of the HESS). The load profile is approximated with five periods of steady-state operation. The operation is rule-based. Objective: minimize the annualized cost of the system that includes capital, fuel, maintenance, and emissions cost. Only the size of PV (kW) and battery (kWh) are determined. Algorithm: MINLP problem implemented in GAMS 23.6 software and solved using the SBB solver. GAMS: General Algebraic Modeling System. * [PERSON] et al. (2019) [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON] _Energy Conversion and Management_**2019**. System to be optimized: hull, water jet, and building integrated photovoltaic (BIPV) system including a battery of a planing craft with water jet propulsion operating in a river. Design optimization. Six optimization problems are formulated and solved. Objectives: (i) lifetime fuel consumption, (ii) overall propulsive efficiency, (iii) total ship resistance, (iv) GHG emissions across the entire operating range, and (v) total cost. Two of the five objectives are selected for each optimization problem in a biobjective optimization. Algorithm: Nondominated Sorting Genetic Algorithm (NSGA-II). * [PERSON] et al. (2019) [PERSON]; [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON] _Journal of Marine Science and Technology_**2019**. System: diesel-mechanical with shaft generator or hybrid electric power system including a battery, with the shaft generator being able to operate as motor in fishing boat. Operation optimization. Series of six steady-state operation modes. Objective: minimize fuel consumption. Independent variables: the power output of each component. Algorithms: combined use of NLopt and COBYLA. * [72] [PERSON]; [PERSON]; [PERSON]; [PERSON] _Journal of Marine Science and Technology_**2019. ** Extension of the previous work that includes comparison among different options of propeller (FPP and CPP) and propulsion control (pitch, speed, or both). * [73] [PERSON]; [PERSON]; [PERSON]; [PERSON] _Energy_**2019. ** System: plug-in hybrid electric propulsion systems (HEPSs), including the diesel engines, motors, battery modules, and gearboxes in tug ship. Design optimization: determine the size of major components of the system. Rule-based energy management. Two operating modes are considered: transit mode and loading mode. Biobjective: (i) minimize fuel consumption and (ii) minimize GHG emissions. Algorithm: NSGA-II. * [74] [PERSON]; [PERSON]; [PERSON]; [PERSON] _Energy_**2019. ** System: alternative BOG rela liquefaction systems in LNG carrier.