It is demonstrated that energy input for fracture in many industrial processes can be optimised so that the energy cost of the process is minimised. Using a simple example of central crack it is shown that for a certain shape of the load pulse energy transmitted to the sample in order to initiate the crack has a strongly marked minimum. Received results indicate a possibility to optimise energy consumption of different industrial processes connected with fracture. Possible applications include drilling or rock pounding where energy input often accounts for the largest part of the process cost. Using this approach it will be possible to predict optimal operational parameters for bores, grinding machines, etc. and hence significantly reduce the process cost. In the second part of the paper the behaviour of energy input for initiation of fracture in conditions of contact interaction is studied. It is considered that a spherical particle is impacting the half-space. Stress field created as a result of the interaction can be estimated using the Hertz solution. Threshold particle velocity (and, hence, threshold kinetic energy) corresponding to initiation of rupture in the half-space can be found once the fracture criterion is defined. It will be shown that the value of this energy does significantly depend on load duration and has a marked minimum. Existence of energetically optimal modes of dynamic impact is claimed.