Xavier Rixhon followed the double degree program TIME. This allowed him to be graduated as electro-mechanical/energy engineer from UCLouvain and aerospace engineer from ISAE Supaero, in Toulouse. After more than two years as design engineer in the lubrication equipment department at Safran Aero Boosters, Xavier decided to shift his career to a more energy-transition oriented topic. During his thesis, Xavier is focusing on WorkPackages 1 and 2. His thesis consists, on one hand, in integrating electro- & synthetic energy carriers into the Belgian energy system model in order to answer the question “How much liquid and gaseous energy carriers do we need to feed the Belgian energy system during and after the transition?” On the other hand, to take into account the variability of model input and parameters, uncertainties qualification/characterization help to get a robust optimization of the energy system.