Shipboard electrification : emission reduction and energy control

Abstract

The application of green technology to marine transport is high on the sector’s agenda, both for environmental reasons, as well as the potential to positively impact on ship operator running costs. In this thesis, electrical technologies and systems as enablers of green vessels were examined for reducing emissions and fuel consumption in a number of case studies, using computer based models and simulations, coupled with real operational data. Bidirectional auxiliary drives were analysed while providing propulsion during low speed manoeuvring, coupling an electrical machine with power electronic converter and feeding power to the propulsion system from the auxiliary generators. Models were built to enable quantification of losses in various topologies and machine setups, showing how permanent magnet machines compared to induction machines, as well as examining different losses in different topologies. Another examination of topologies was performed for onshore power supply systems, where a number of different network configurations were modelled and examined based on the visiting profile for a particular port. A Particle Swarm Optimisation algorithm was developed to identify optimal configurations considering both capital costs as well as operational efficiency. This was additionally coupled with the consideration of shore-based LNG generation giving a hybrid onshore power supply configuration. Hybrid systems on vessels are more complex in terms of energy management, particularly with on-board energy storage. Particle Swarm Optimisation was applied to a model of a hybrid shipboard power system, optimising continuously for the greenest configuration during the ship’s voyage. This was developed into a generic and scalable Energy Management System, with the objective of minimising fuel consumption, and applied to a case study.