Using XRD method it was revealed that in the stress-strain state of Al nanopowder lattice a non-significant amount of energy was stored (~0.385 J/g). Nevertheless, according to the data obtained by differential thermal analysis (DTA) the total amount of stored energy in the nanopowder was 348 J/g. The estimated value might be caused by the significant contribution of nanoparticles surface energy, which cannot be detected by means of XRD method. However, the method proposed in the paper can be applied to estimate changes in the structural and energy states of the lattice for nanoparticles or another micro-and nanopowders.