The shipping and cruising industry is considered one of the most important and cheapest transportation, however, it is considered responsible for almost 2.89% of global emissions in 2018. Due to the new regulations provided by IMO, the need to reduce fuel consumption and emissions from the shipping industry becomes imperative. Several technologies have been applied to achieve those challenges, but the main focus of this thesis will be on the utilization of batteries as one of the most promising energy storage technologies, to handle the load variation rather than the operation of the auxiliary diesel engines at an economical loading range.
In cruise ship applications, the auxiliary diesel engines are utilized to supply the power required for the auxiliary loads and thruster motors, usually, thruster motors operate close to harbors. So, to ensure power availability, the auxiliary diesel engines usually run at low loading levels. The optimum operating point for the diesel engines is at 80% of loading, if that percentage decreases, both fuel consumption, and NOx emissions increased exponentially, moreover, the engine’s lifetime will be reduced and more maintenance will be required. By utilizing batteries, it will be capable of providing the required power for the operation of thruster motors or during peak loading periods rather than the operation of all available auxiliary diesel engines at low loading levels.
The presented study focused on four different scenarios with different battery-pack sizes, showing the space required for each scenario and the operating profile of each diesel engine indicating the fuel consumption with and without the presence of batteries. The first scenario utilized a 940-kWh battery pack, which increased the efficiency of the running engines close to the optimum operating level. The last scenario utilized a 3240-kWh battery pack, which enables the shutdown of the auxiliary engines during the operation of thruster motors or peak loading. By using the large battery model scenario, half the number of diesel engines will not be required in the future new builds of a cruise ship. This will not only improve the fuel consumption efficiency and reduce emissions, moreover, the maintenance and overall build cost will also be reduced. Technical and economic analysis is presented showing the payback period of the batteries with different fuel and battery price options. The payback period is highly affected by the saving associated with fuel costs and the price of batteries.