For the investigation of the possible energy conversion in the atmosphere on the scale of the general circulation, one has to introduce a state of mean motion such that the averaged quantities vary slowly from one point to another and from one instant to another. This condition is fulfilled when the averages are taken for a domain of space, or for a space-time domain which is large with respect to the volume and the local lifetime of the perturbations imbedded in the mean flow. Only mean values along vertical lines will be considered here. At first we recall the energy equations for the non averaged motion, deduced from the equations at atmospheric dynamics and from the first law of thermodynamics. The, we establish the corresponding equations for the vertically averaged motion and for the large-scale eddying motion (thermal wind). These energy equations assume the form of an equation of balance from which it is easy to deduce the energy fluxes and the rates of energy production and conversion. The established energy equations are applied to the large atmospheric disturbances. It is shown that the main energy conversation occur between the potential energy and the kinetic energy of the thermal wind, and between the kinetic energy of the thermal wind and the kinetic energy of the vertically averaged motion. The same energy equations may be applied to the atmospheric “models” and from the equation of the vertically averaged motion a basic equation of these “models” is deduced in suc a way that all the simplifying assumption appear clearly. Finally the energy transformations in a thermally and mechanically isolated system are envisaged.