This paper has an energy consumption reduction perspective by considering alternative machining strategies and system components interactions translated into variable and constant power flows with respect to various use phase regimes of a machine tool system. The methodology is able to estimate the mechanical energy requirements of the spindle and feed axes with respect to 2.5D machining strategies by taking into account steady-state and transient regimes. In addition, the specific amount of fixed energy drawn by a machine was determined based on a careful monitoring of the energy share amongst the auxiliary equipment that supports the accomplishment of the machining tasks. The numerical results were experimentally validated and the good agreement between them led to the conclusion that the proposed methodology can be used effectively for the calculation of the total energy required by a machine tool system for the milling of a part. This enables a straightforward comparison of different milling part programs with respect to their energy consumption levels. (C) 2010 Elsevier Ltd. All rights reserved.