The emergence of new big consumer countries on the energy markets and the perspective of oil and gas depletion at the end of the current century raise the concerns about fair distribution of the remaining resources for the common and sustainable wellbeing of the mankind. High volatility of energy prices discourages the investment and delays the energy technology transition. Voluntary measures are needed mainly in industrialised countries in order to develop alternative and sustainable energy sources, to enable technology transfer towards emerging and developing countries and to avoid struggle for energy procurement. In this paper a composite index of energy demand / supply weaknesses is defined as a proxy of energy vulnerability. The proposed index is based on several indicators such as energy intensity, oil and gas import dependency, CO2 content of primary energy supply, electricity supply weaknesses and non-diversity in transport fuels. The assessment of this composite index for selected industrialised countries is discussed as well as the sensitivity to various factors.