Summary: The complexity of mobile devices is continuously growing due to the increasing requirements on performance. In portable systems such as smart cards, not only performance is an important attribute, but also the power and energy consumed by a given application. It is mandatory to accomplish software power optimizations based on accurate power consumption models characterized for the processor. Both the optimization and the characterization are carried out mostly manually and are thus very time consuming processes. This paper presents an environment for automated instruction set characterization, based on physical power measurements. Further, an optimization system is presented that allows an automated reduction of power peaks based on a compiler optimization.