This paper presents a procedure for assessing the failure risk of metal oxide (MO) surge arresters intended for the protection of wind turbines (i.e. wind farms), due to the energy that they must be able to absorb during a direct lightning strike to the wind turbine. The calculation procedure is statistical in nature and is based on Monte Carlo simulation, using the well-known EMTP-ATP software package. It takes into account the fact that the lightning current parameters incident to the wind turbine (amplitude, front duration and crest duration) are of a statistical nature, as well as the energy carrying capacity of the metal oxide surge arrester itself. In addition, the proposed procedure also takes into account the fact that the wind turbine, as a free-standing, exposed and very tall object, initiates its own upward lightning strikes (the parameters of which differ significantly from downward lightning strikes). In this regard, the basis for determining the energy stress of the ZnO surge arrester is the analysis of the so-called backsurge that accompanies a direct lightning strike to the wind turbine.