This invention relates to a system level power evaluation method in which detailed power macro-models (PMM) are created for operations of modules. These PMMs are stored in memory. A system level circuit description (SLCD) is evaluated using the PMMs stored in memory that are relevant to that SLCD and using other PMMs that are generated for operations of modules that do not have PMMs stored in memory. In this way, a highly accurate and computationally efficient power evaluation of the SLCD is possible. Furthermore, the user implementing the method may define a case, which relates to an operation of a module and has a PMM associated therewith, in a highly flexible manner that allows for more abstract analysis of the SLCD to be carried out. A case may relate to single operation of a module, a plurality of operations of a module or operation(s) of a plurality of modules.