The article presents the results of the calculation of the energy consumption of the main and auxiliary technologies for the production of mineral fertilizers, interrelated as a single energy technology system (ETS). At the stage of the primary analysis of fuel, electricity and heat consumption indicators of individual technologies of the mineral fertilizers industry, the task was set to determine the energy intensity of specific technologies depending on intra-system distribution of flows of fuel and energy resources (FER) between the ETS production facilities for the output of target products.On the basis of a mathematical model, according to the averaged specific consumption rates of fuel and energy resources of the main and auxiliary technologies for the production of one ton of product, the values of specific energy consumption for target technologies for the production of mineral fertilizers were obtained. The analysis of the calculated indicators of energy consumption enabled to identify the most energy-intensive technologies.. It is shown that in the total energy consumption of the target technology, the share of energy consumption of auxiliary industries is up to 97% of the total energy intensity. Besides, the paper cosiders the key factors that determine the level of energy efficiency of industry enterprises under study.Through the example of an existing technology for the production of mineral fertilizers of one technological line with a capacity of 27.5 t/h (in terms of the finished product), the calculation of energy consumption was performed. The paper states that the modernization of the technology for the production of mineral fertilizers through the utilization of thermal SERs emitted into the environment would reduce the energy consumption of the technology by 6.33%.The mathematical model used in the study makes it possible to determine the values of energy consumption of technologies in the mineral fertilizer production industry with the greatest accuracy. The analysis of the data obtained shows that the studied technologies of the industry are characterized by irrational consumption of fuel and energy resources and, therefore, need a more thorough and systematic approach in determining energy saving reserves and ways to rationalize them in the energy technology system (ETS).