This paper contributes to the analysis made by an article recently published in this journal [1]. The purpose of this manuscript is to bring new contributions to this complex subject, namely the limits to the penetration of variable renewable energy (VRE) into national grids. A detailed and advanced model has been used in this work in order to add further contributions to De Jong et al. [1] findings. For example, by applying an optimization model, we were able to show that the high wind penetration (65%) almost without curtailment found by [1] might not happen, mainly due to inflexibility constraints in Brazilian power plants and also to transmission limits. (C) 2016 Elsevier Ltd. All rights reserved.