Enhancing the energetic performances of wind power systems still represents an actual interest and challenge for the researchers in this domain. Considering this desideratum, the paper aims at the kinematic optimization of a planetary speed increaser, targeting the maximizing the energetic performances of a reconfigurable counter-rotating wind energy conversion system. This wind system consists of a speed increaser with two inputs and two outputs that connects two counter-rotating wind rotors with a counter-rotating electric generator, capable of functioning both as monomobile and differential mechanisms. The switch between these functioning cases may be obtained by commanding appropriately a coupling. Considering the generic case of a counter-rotating wind system with five external connections, the equations regarding the areas of kinematics and statics for the speed increaser are firstly described, with the input torques of the two wind rotors, the output torques (i.e. input torques of the counter-rotating generator) and the interior efficiency of the planetary transmission as known values. The mechanical transmission consists of two planetary units, hence two internal kinematic ratios (i01 and i02) are involved as input variables in the process of energetic optimization. In this way the feasible domains of variation for the transmission ratios and the optimal solution (i01, i02)opt maximizing the mechanical energy at the generator input can be identified, separately for both differential and monomobile wind system, respectively (Case A). The common variation range of the transmission ratios, where both differential and monomobile systems are functioning is as well established (Case B). The optimal solution for Case B represents a reasonable compromise between the energetic performances of the two wind systems. By converting the analytical model in a numerical simulation with the help of the Matlab-Simulink software, a series of results were obtained that highlight the advantages and disadvantages of the monomobile vs. differential counter-rotating wind system. In the case study of the analyzed reconfigurable wind system, it was revealed that the monomobile speed increaser brings a major energetic advantage; however, it has the drawback of higher complexity and cost.