The search and development of alternative energy sources for human life is a priority task for modern society. One of the promising directions is the use of biogas as a source of thermal energy for power plants. It is established that the main difference between biogas and natural gas is caused by the presence of more than 30% of carbon dioxide in its composition, which affects the density, calorific value and speed of flame propagation. To burn biogas in modern power plants that use natural gas, it is necessary to modify the burner devices. For qualitative modification of burner devices, it is necessary to have theoretical data on effective modes of biogas combustion. In combustion, we present a model of turbulence k-s (realizable), which allows us to model the combustion of natural gas and biogas with tangential air swirl. The paper presents qualitative characteristics of biogas that allow us to analyze and develop a theory about efficient combustion of biogas in power plants.