Equations are derived and analyzed that interrelate the quantities of the ideal activation energy W (determined at a constant Galvani potential value), the real activation energy A (measured at a constant overpotential value) and the so-called formal activation energy Omega (measured at a constant electrode potential vs. an arbitrarily chosen reference electrode). The mathematical forms of dependence of apparent formal activation energy on electrode potential are established. It is shown that using formal activation energy (measured at a constant electrode potential) is applicable for kinetics analysis of various electrode processes. The expressions obtained in this study may be used when processing temperature dependences of highly irreversible electrochemical reactions. (C) 2010 Elsevier B.V. All rights reserved.