The energy efficiency of the integrated steel plant is studied basing on the Intensive Energy Conservation Methodology. The primary diagnostics of the energy efficiency of the integrated steel plant is carried out. The boundaries of the object of study are established from iron ore deposits to the finished steel cold-rolled sheet. The research object is presented in the form of a directed graph, and the flows of materials in this network are calculated. The thermophysical heat absorption of materials and intermediates within the boundaries of a closed heat engineering complex has been estimated. The energy intensity of the cold-rolled steel sheet within the same boundaries has been calculated. Efficiency of production was estimated by comparing heat consumption and energy intensity. The complete intensive energy conservation reserve in the complex has been determined. Reserve structure is studied and directions of its implementation are discussed. It is shown that the most complete implementation of the energy-saving reserve is possible only with the transition of a new generation of steel engineering and technology.