A New Perspective on the Complexity of On-board Primary Power Systems

Abstract

The applicability of different selection methods for power systems on board ships is highly dependent on the number of options possible. With the introduction of new technologies in the maritime sector, this number is increasing. However, its exact value, or even its order of magnitude is still unknown. This article shows the complexity of modern on-board power system by quantifying the number of possible system configurations currently available. A constraint satisfaction algorithm generates different configurations and the results are supported by combinatorics principles. The set of constraints used led to a significant reduction in the design space, and the influence of each of the constraints is investigated independently. Traditional mechanical propulsion is present in less than 1% of the generated configurations, whereas electric and hybrid propulsion are dominant. In particular, the impact of energy storage on the size of the design space is made evident. The order of magnitude of the total number of configurations obtained supports the use of modern selection methods instead of ones based on expert intuition and past experience. The presented work offers a tool to determine and restrict the size of the design space. It can therefore be integrated into existing selection methods and is a starting point for the development of new ones. 1. Introduction Ship design has undergone drastic changes in recent years as computers are used more and more to manage the large number of design choices. Until recently, the configuration of the on-board power system has been a relatively straight forward decision because of the predominance of mechanical propulsion. However, several new technologies have been developed in recent years, most of which aim to improve the energy systems on board ships. Several more are currently under development. Modern on-board power systems may have an alternative energy source through different fuels, more complex configurations sometimes including energy storage, exhaust-gas treatment or a combination of these.