The increase of renewables in power sector, together with the increase of their electricity share in final energy consumption, is changing our perception about energy security with diverse and contradictory statements. The Portuguese security of electricity supply is analyzed in this study by comparing selected indicators for 2 years before and after the high increase of onshore wind since 2005. Our goal is to find how the security of electricity supply was impacted by the penetration of renewables, taking a supply chain approach. Our analysis highlights that the penetration of renewables has decreased the energy dependence of the power sector by more than 20% between 2004 and 2011, while risks related to the concentration of natural gas suppliers and to the still-high share of fossil fuels suffering from price volatility are discussed. We observed a significant improvement in power interconnections with Spain, as well as an increase of the de-rated generation capacity margin, allowing proper management of renewable power intermittency if necessary, thereby improving power security. Although the share of intermittent renewables almost quadrupled in total installed capacity between those years, the indicators reveal an improvement in the quality of transport and distribution when delivering electricity to end-users. Although electricity prices increased, mainly due to taxes, the lack of energy efficiency is an aspect deserving improvement to alleviate the pressure on electricity security, mainly at high peak demands. (C) 2014 Elsevier Ltd. All rights reserved.