To support its activities in the field of conventional and hybrid vehicles, TNO has developed ADVANCE, a modular simulation tool for the design and evaluation of advanced powertrains. In this paper the various features and the potential of ADVANCE are described and illustrated by means of three case studies. The first case describes the application of TNO ADVANCE for the development of test procedures for vehicles with advanced propulsion systems. In the second case the use of ADVANCE is described in the development of a system integrated powertrain for passenger cars, which makes use of a continuously variable transmission and an internal combustion engine (ICE), optimised for this transmission type. The application of a starter alternator set for this system integrated powertrain is evaluated in case three.