This report presents output from ensemble dispersion simulations performed by CONFIDENCE work package 1 (WP1). It presents the Borssele case study. The case description, a list of the participants and the models used for the calculations are given. Ensemble results are summarized for the “short release” scenario. Results are shown for ensembles using only meteorological uncertainties, and with those including source term perturbations. A preliminary analysis and visualization products are proposed.