Energy terms were computed in a set of undrained cyclic triaxial discrete-element method simulations which form a parametric study of five factors: void ratio, initial mean effective stress, mean deviator stress, deviator stress amplitude and compressive/extensive initial loading. Void ratio is the only one of these factors which significantly affects the relationship between the excess pore water pressure and the unit energy dissipated (energy dissipated per unit volume). The trends in both the number of complete cycles and the unit energy up to the onset of liquefaction match experimental data. Through analysis of the micro-scale particle and contact information, a preferred contact orientation for frictional dissipation of 30–40° was found. Following a shear reversal, there is a period of negligible frictional dissipation in these simulations of around 0.04% axial strain. This explains, from an energy perspective, why many load cycles are needed to induce liquefaction if their amplitude is very small. A commonly used energy-based model to evaluate the liquefaction potential of a soil was assessed. A substantial improvement in the predictive ability of this model may be achieved by including the mean deviator stress.