Conventional technologies based on use of fossil fuels significantly contribute to the environmental load. Increasing efficiency of heat supply, resulting in rational use of fossil fuels, is a primary condition of sustainable energy supply. This increase is limited by the validity of basic laws of thermodynamics. Moreover, regardless of the maximum effectiveness of fossil fuels’ utilization, sustainability of the energy supply is limited to several decades. This paper describes some basic approaches to long-term sustainability under conditions of the European Union. The validity of these approaches is, however, universal and can be applied globally.

Units: SI