The features of electric hydraulic complexes with position problematic issues of energy resourcesaving. It is shown that for solving improve the performance of electric hydraulic systems is a very important matter of assessing their power controllability taking into account the multiple handling of the energy states of the power channel, non-unidirectional flow of energy, availability of energy storage devices of various kinds, the development of nonlinear hydrodynamic processes. Noted that a promising direction to improve the power controllability of electric hydraulic complexes is the use of reversible modes of operation of hydraulic and electric machines that extend the adjustment possibilities of pumping units and lead to increased process reliability. The scientific foundations of the theory of increasing power controllability of electric hydraulic complexes, which are based on the analysis of energy conversion processes at all levels of the power channel using the harmonic analysis of the time of the power function. Main expression, reflecting processes of energy transformation is the law of conservation of energy, represented by the balance equations of the harmonic components of power for all elements of the power channel of the system. Found that estimationof the quality of power processes in the system is the mean-square power. Proposed indexesfor assessing the capacity of the power channel and power controllability that characterize the real state of the electric hydraulic complex. It is proved that the presence of the variable components of power, reflecting the energy-exchange processes in the system leads to lower power controllability of object. Evaluation methods, analysis and control in electric hydraulic complex allows you to define the energy losses and reserve energy resourcesaving.