Nowadays, manufacturing environment is characterized by the necessity of customized flexibility as well as coping rapidly and cost-effectively to changing market demands. These challenges must be fulfilled while minimizing impacts on the environment and the society. To reach these goals, a key paradigm called sustainable manufacturing can be coupled with reconfigurable manufacturing systems (RMSs). The coupling of sustainability concerns with RMS characteristics is a basis to develop a new generation of sustainable production systems. This paper outlines sustainability in a reconfigurable environment from an energy consumption point of view. A non-linear mathematical model is developed to optimize the energy consumption in an RMS through a redefinition of two of its core characteristics, i.e., modularity and integrability. The objective is to minimize the energy consumption of the system by selecting the most suitable modular machines from a set of candidate machines. The optimization problem is addressed using an exhaustive search heuristic algorithm. Finally, the applicability of the proposed heuristic is demonstrated through simple illustrative numerical examples and the discussions of the obtained results