Relevance. The urgent task of technical and economic development of the northern and eastern regions of Russia is to provide reliable and efficient power supply to consumers, geographically located in remote, hard-to-reach areas. The use of hybrid energy systems with renewable energy sources is a promising way to solve this problem. A characteristic feature of the modes of hybrid systems, especially with a high level of fuel replacement, is the presence of ripples in charge-discharge currents of batteries used as energy storage devices. The operation of batteries in the mode of pulsed currents leads to rapid degradation of their characteristics and reduction in the service life, which leads to decrease in reliability of the power supply system and increase in the cost of generated electricity. A significant drawback of hybrid systems built according to well-known standard schemes is the inefficient use of the potential of primary renewable energy, which is especially critical for power systems geographically located in areas with severe climatic conditions. The article proposes technical solutions to eliminate the indicated problems. Aim of the study is to search for and develop technical solutions to improve the efficiency of hybrid energy systems with a high level of fuel substitution. Methods: mathematical and computer modeling using the Matlab/Simulink software environment. Results. We offer a new method of construction and control algorithm of the modes of hybrid energy systems, which provide increasing their reliability and energy efficiency. The results of the modeling and the operating modes of a hybrid power plant with a high level of fuel substitution are presented, which proves that the proposed method of construction and the control algorithm provides reliable and efficient control of the power balance of a hybrid power system in all possible operating conditions. The application of the proposed algorithm in a dual-circuit energy storage device provides 5,7 % reduction in the failure rate of the hybrid power system, increasing the operating life of the batteries by 50 %, more efficient use of renewable energy by 28 % compared with conventional methods of construction of hybrid plants.