Abstract/Summary: An experiment done in Geneva on the river Rhne with a push boat gave the practical frame of a comparative study between 3 fuels: diesel, biodiesel and vegetable oil. Further more in this concrete case the VO used, came from frying oil waste constitutes an interesting illustration of industrial ecology. The asset of this study on environmental impacts analysis done here is to have used practical measurements of emissions from an engine in function on the push boat in complement to bibliographic sources and Data Base. Investigating the sensibility of such analysis shows that there are still questions to be answered and that this field is still subject for research. Finally, it confirms that the environmental gains of biofuels scenarios are not as important as expected, if their vegetable raw material is produced uniquely for energy as in the transport function. They are much more interesting when used in an industrial ecology context where a first cooking function allows dispatching of the production's impacts.