The fundamentally new approach to the energy problem based on the excitation of elec- tronic quantum transitions in atom responsible for the increase in the mass defect of atom is put forward. The logically consistent quantum theory of hydrogen atom as a system of two particles interacting with each other - electron and proton - is constructed on the basis of the Dirac model of electron. It is indicated that the motion of nucleus in the hydrogen atom significantly influences the physical properties of the atom. The energy spectrum of the atom contains two regions of bound states of electron and nucleus separated from each other by energy on the order of 2 2 2 c m ( 2 m is the mass of proton, c is the velocity of light). As a consequence, there exist such states of the atom in which the mass defect of atom reaches the value of 1 2m ( 1 m is the mass of electron). The existence of quantum states of atom with abnormally high mass defect and the ability of atom to make transitions from states with smaller value of mass defect to states with greater value open the prospect of creation of active thermal machines (ТМ) producing excess energy, i.e., transforming the energy of environment into an active one. From the conceptual point of view, the idea of production of excess energy in active ТМ does not differ from the physical one, which is carried out in the thoroughly studied reactions of thermonuclear synthesis. In both cases, the question is the organization and maintenance, in a system of interacting particles, of physical processes in which the state of system changes in such a manner that the mass defect of system eventually increases in comparison with the initial mass defect. Distinction between active ТМ and thermonuclear reactor lies only in the fact that physical processes of various types are used in them: in the first case - electronic processes in atoms, and in the second one - the processes going on at collision of nucleons and nuclei. The fact that both phenomena – the production of excess energy in active ТМ and the energy release in reaction of thermonuclear synthesis – are of the same physical nature and are described by the same parameter - the mass defect, means that production of excess energy is as real as thermonuclear synthesis. As the energy release in active ТМ occurs due to electronic processes in atoms instead of synthesis or splitting of atomic nuclei, active ТМ will be ecologically pure energy sources. As fuel for active thermal machine, any substance can serve, the atoms of which can be in the states with various values of the mass defect. The results of the present work do not contradict the laws of thermodynamics. The principles of action of ТМ described in textbooks on thermodynamics refer only to such ТМ, which are isolated from the environment (such ТМ can be called passive ones). The idea that it is impossible to transform energy of the environment into an active form, deeply rooted in consciousness, is the deepest and the most tragic mistake of the last century resulted in the orientation of the planet economy exclusively towards passive ТМ. Consequences are known: researches of the transformation of environment energy into active form (N. Tesla, K.E. Tsiolkovsky, P.K. Oshchepkov) have been stopped and declared as pseudo science; that is why, by the end of the century, the mankind turned to be on the verge of ecological catastrophe. The real way to the energy problem solution, as the results of the paper show, passes through the research directed to the creation of active thermal machines, qualitatively new ecologically pure sources of energy. Production of excess energy in active TM is not in conflict with energy conservation. As a matter of fact, an active TM merely converts the poor-quality-energy of surrounding medium into the high- quality-energy capable of performing useful work. The total energy in nature remains constant, and only some part of it becomes active.