Intertemporal Static and Dynamic Optimization of Synthesis, Design, and Operation of Integrated Energy Systems of Ships

Abstract

Fuel expenses constitute the largest part of the operating cost of a merchant ship. Integrated energy systems that cover all energy loads with low fuel consumption, while being economically feasible, are increasingly studied and installed. Due to the large variety of possible configurations, design specifications, and operating conditions that change with time, the application of optimization methods is imperative. Designing the system for nominal conditions only is not sufficient. Instead, intertemporal optimization needs to be performed that can be static or dynamic. In the present article, intertemporal static and dynamic optimization problems for the synthesis, design, and operation (SDO) of integrated ship energy systems are stated mathematically and the solution methods are presented, while case studies demonstrate the applicability of the methods and also reveal that the optimal solution may defer significantly from the solutions suggested with the usual practice. While in other works, the SDO optimization problems are usually solved by two- or three-level algorithms; single-level algorithms are developed and applied here, which tackle all three aspects (S, D, and O) concurrently. The methods can also be applied on land installations, e.g., power plants, cogenerations systems, etc., with proper modifications.

A Vessel Schedule Recovery Problem at the Liner Shipping Route with Emission Control Areas

“…The proposed GVSRP mathematical model is nonlinear due to constraint set (15), which was used for estimating the actual vessel sailing time at each voyage leg, and constraint set (16), which was used for estimating the actual fuel consumption at each voyage leg. In order to linearize constraint set (15), the actual vessel sailing speed s p , p ∈ P was replaced with its reciprocal v p = 1 s p ∀p ∈ P. Similarly, the planned vessel sailing speed s p , p ∈ P will be replaced with its reciprocal . v p = 1 s p ∀p ∈ P. Also, the expected vessel sailing speed change due to a disruptive event at a given voyage leg (δ sea p , p ∈ P-measured in knots) should be adjusted accordingly.…”

“…Constraint sets (13) and (14) define the limits of the vessel sailing speed at each voyage leg of the liner shipping route, passing through ECAs. Constraint set (15) calculates the vessel sailing time for the recovered vessel schedule at each voyage leg of the given liner shipping route, passing through ECAs. Constraint set (16) estimates the fuel consumption for the recovered vessel schedule at each voyage leg of the given liner shipping route, passing through ECAs.…”

“…The proposed methodology (i.e., the mathematical model and the solution approach) will assist liner shipping companies with efficient vessel schedule recovery, minimizing monetary losses endured as a result of disruptions in vessel schedules, improving energy efficiency and environmental sustainability throughout the transportation process. The latter aspects are considered as critical [12][13][14][15].…”

Optimum Choice of Energy System Configuration and Storages for a Proper Match between Energy Conversion and Demands

“…Sakalis et al [1] supply very general and detailed information about the mathematical formulation, solution methods, and case studies of intertemporal static and dynamic optimization problems for the synthesis, design, and operation (SDO) of energy systems. The focus is on the energy systems aboard ships.…”

Design and Analysis of New Harbour Grid Models to Facilitate Multiple Scenarios of Battery Charging and Onshore Supply for Modern Vessels

“…Shipboard power systems have developed from thermal to electrochemical, stored and hybrid power systems [4,13]. The modern AES has an integrated power system consisting of several generators including renewable sources and energy storage; it behaves like an islanded microgrid with a power capacity of up to 100 MW [14][15][16][17][18][19][20][21][22]. The AES is believed to be the most efficient ship, replacing the conventional mechanical drive system with electric propulsion.…”