Efficiency improvement on a cruise ship: Load allocation optimization

Abstract

Last years have been characterized by a worldwide increasing attention towards the reduction of fuel consumption and carbon dioxide emissions. Several industrial fields, as well as the civil and residential sector, have introduced innovative approaches for the design and the operation of energy systems. These actions are aimed to reach higher values of energy conversion efficiency, also including an increase in the use of renewable resources. In this context, especially in the sector of cruise ships, further efforts are required to improve the energy efficiency of the employed energy systems. The aim of this paper is to propose an optimization framework based on genetic algorithms in order to maximize the energy efficiency and minimize both the fuel consumption and the thermal energy dissipation, by optimizing the load allocation of the ship energy systems. To this purpose, different strategies for the energy systems on board of an existing cruise ship are proposed and analyzed. In particular, two main engines configurations have been defined: standard (current logic of operation maintained) and hybrid configuration. For each proposed strategybeing the ship a particular and interesting application of isolated energy grid (i.e. a grid without connections with electric and fuel national grids)an in-house-developed software has been adapted and applied to optimize the load allocation of the various energy systems. Furthermore, an economic and environmental analysis has been carried out, in order to point out the benefitsor the eventual limitsrelated to the proposed solutions. The considered approach is based on the concept of introducing economically and structurally suitable modifications to the current cruise energy systems configuration, in order to reach the goal of increasing the energy efficiency. The carried out analysis shows that the hybrid strategies allow to reach the best results in terms of energy (fuel consumption and heat dissipation reduction), economic and environmental points of view.

Impact of carbon pricing on the cruise ship energy systems optimal configuration

“…The load allocation with economic considerations of a hybrid system has been discussed in [22]. The energy efficiency of a hybrid system was optimised in [7]. The simulation of the performance of a hybrid system that includes fuel cells and batteries was presented in [23].…”

“…However, despite this regulatory framework, the shipping operations still have a great impact on the worldwide CO2 emissions and it is forecasted that even though shipping now accounts for only 2.2% of the global CO2 emissions, it might reach 17% by 2050 if no measures are taken [5]. A reduction of carbon emissions around 90% is required from 2010 to 2050 [6] in order for the shipping operations to contribute beneficially to the global target of keeping the temperature increase below 2 o C. Recently the IMO, acknowledging the significant contribution of the shipping operations on the global carbon emissions, set a target on CO2 emissions from ships [7]. Along these lines, it has been discussed to introduce shipping operations into the European Emission Trading Market Scheme (EU ETS) for CO2 emissions [8] as well as to tax the carbon emissions, similarly to the land-based power plants.…”

Active Whale Avoidance by Large Ships: Components and Constraints of a Complementary Approach to Reducing Ship Strike Risk

“…For large cruise ships (and likely other large ships) power management plays a major role in operational decision-making (e.g., Ancona et al, 2018), not just in the context of managing fuel costs and optimal fuel efficiency (and resulting levels of air pollution; Khan et al, 2012), but also for safety reasons. For large cruise ships, power needs are met using multiple engines that are variably configured for two different power loads including the propulsion load, which is typically about 80% of total load while transiting, and the hotel load, which is the electrical energy needed to power the ship's lights, heating/air conditioning, galley, etc.…”

Comparative Analysis of Linear and Non-Linear Programming Techniques for the Optimization of Ship Machinery Systems

“…For this reason, many authors proposed the use of non-linear approaches, such as the implementation of MINLP. Ancona et al [10] utilized a genetic algorithm to optimize the load allocation of the various energy utilities on board a cruise ship. Their study considered a fixed machinery layout, where the load of the different engines could be optimized.…”

“…Previous works presented in literature aimed at identifying the optimal machinery system configuration to be installed on board a vessel by using either a MILP [7][8][9] or MINLP approach [10][11][12][13][14][15][16][17], but did not quantify the inaccuracies in the attained solutions due to the linear approximations, nor clarified which approach is the most suitable for the considered problem.…”