Fuel cell systems require a better early-stage prediction of the energy consumption of a ship because they are more expensive, more voluminous and less able to deal with rapid load changes than conventional diesel-powered systems. This paper discusses a model for such an improved prediction of the total energy demand of an expedition cruise vessel. The focus is on identifying the peak loads and load changes under consideration of the passenger behaviour, environmental and operational conditions. The used bottom-up approach builds up a parametric model for the early design stages with limited required input data by using typical operational conditions for this type of vessel. The paper concludes that the method provides more insights into the dynamic power and substantially lower predicted energy use. @en