Zero emission cruise shipping

The goal of the project was to describe an exploration cruise vessel with sufficient range based on machinery systems with zero or very low emissions of greenhouse gases. The project has developed methods that enable estimation of contributions from wind assisted propulsion and also models for total energy production onboard based on hybrid machinery configurations. The project has developed methods for estimation based on data for hotel loads from real vessels in the same category. Propulsion and hotel are the main consumers of energy onboard a cruise vessel. This project has its focus on the exploration cruise segment in which vessels operate within a given area but not on a fixed route. These vessels typically operate in the global summer season, i.e. on the northern hemisphere during northern summer and the southern hemisphere during southern summer. As an example they will sail the waters of Iceland and Svalbard for 6 months then switch to Antarctica from South America the next 6 months. The propulsive power for the vessels must ensure the ability to maneuver during bad wether while also providing the ability to avoid bad weather. Since the vessel is not on a regular route and schedule it has a greater window for use of sails. This can substitute the use of engines during parts of the route, either partially or entirely. Modern sail technology includes sof sails, rigid sail and rotating sails (Flettner). The project has developed methods for including the effect of sails in simulations. The project utilizes SINTEF Ocean software for modelling and simulation of vessel operations in defined routes and using real weather data. Models have been developed taking into account the desired track of the vessel to the prevailing wind force and direction to allow a realistic estimation of wind assisted propulsion power. The results show the amount of time the vessel can operate on sails alone, and the necessary minimum machinery power for safe operations under any weather conditions. The project has also developed a method for estimation of energy use by the hotel. The method uses weather and other operational parameters as the foundation for a data driven model. The initial hypothesis was that the hotel load can be correlated to the main propulsion power of the vessel, to the heating, ventilation and air conditioning (HVAC) power and to other consumers. The hypothesis also states that the main correlation will be with propulsion and HVAC, and that other consumption has negligible correlation. The model uses data from several vessels in the same category and size during several cruises. The actual hotel load is known and can thus be compared to model output. Results from the model shows high correlation between hotel load and propulsion power. For external air temperature the results show good correlation when temperatures are averaged over several days. The resulting tools provide a good platform for estimation power and energy use for an exploration vessel, leading to machinery installations that minimize the emission of greenhouse gases.

Methods for prediction of wind assisted propulsion power has been established based on model testing and available literature. The methods have been made available for simulation tools such as the SINTEF Ocean Gymir-tool that enables optimization of wind assisted propulsion for specific vessels and sailing routes. Methods for assessing superstructure design based on different characteristics of sail systems (soft, rigid, rotor) are developed. Method for estimating necessary hotel load has been developed. This is crucial for optimization of the entire energy production system onboard. A design tool for the power and energy system optimization has been developed by the project, in which operational characteristics of the power system is coupled with the energy and power requirements of the vessel. Simulation of a vessel under realitsic routes and weather is performed using the Gymir simulation system. Gymir has been expanded to consider both wind assisted propulsion and the hotel load estimation in order to assess the performance of alternative ship designs.

The shipping industry, and particularly the cruise segment, is facing ever stronger emission-reduction requirements from governments and the public. Stricter regulations on both global GHG-emission and local emission are being introduced, at the same time as the environmental awareness of cruise ship passengers is increasing. It is likely that cruise ships will be required to be emission-free within 2050, and in many areas already within the next decade. According to the Strategy for Green shipping of the Norwegian Government (presented June 2019), only emission-free ships should be allowed to sail the world heritage fjords in Norway from 2026. The strategy also highlights that measures will be put in place to ensure that cruise ships are widely using low- or zero-emission technology already in 2030, both in national and international waters. The R&D centre SFI Smart Maritime initiated in 2019 a feasibility study on zero-emission expedition cruise shipping, with contributions from Vard, ABB, SINTEF Ocean and other partners. The Zero emission cruise shipping (CruiZero) project will bring the study further towards optimized system designs and verification of these, developing solutions for design of future cruise vessels that ensure operation with zero emissions of local pollution and greenhouse gases. There is a need to combine several technology innovations to reduce the energy consumption, in order to allow for design of power systems using green fuels that have a lower energy density than fossil-fuels. Hence, CruiZero will focus on technologies within the areas energy-efficient design, wind-assisted propulsion, energy-efficient hotel and zero-emission power system. Promising technologies will be assessed in operational studies to determine the viability of solutions. The project partners Vard Design, ABB and SINTEF Ocean provides industrial and scientific competence and experience within all these areas.