At present, ensuring reliability is an integral part of maintaining the high efficiency of operation of electric power equipment. The reliability factor can be considered and considered at different stages of solving the problem of optimizing the operation of equipment for thermal power plants, this article will consider the stage of applying for choosing the composition of the main generating equipment, considering reliability. The method for choosing the composition of the main generating equipment, considering the reliability criterion, is described. A technique for calculating the reliability characteristics of equipment and taking them into account when a power plant enters the market is presented. The optimal distribution of the load and the choice of the composition of the equipment, considering the criterion of reliability, are analyzed using the example of different loads of power units.