Energy sustainability: a definition and assessment modelEnergy sustainability: a definition and assessment model Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2022-10-052021enEnergy is the fundamental component of all economic activity and a central ingredient of international politics. Energy is finite and often creates externalities. A fundamental question then arises about its sustainability. Assessing energy sustainability is important since energy is a key factor of all economies. However, energy generation imposes large pressures on the environment and is mostly based on limited resources. Energy sustainability is related with the provision of adequate, reliable, and affordable energy, in conformity with social and environmental requirements. In this paper we develop a mathematical model that defines and measures energy sustainability for a given region or country. It is based on a number of indicators that cover such aspects as environmental impact, access, health, economy, generation, consumption, and security. Statistical methods and fuzzy logic reasoning lead to an index in [0, 1] and a subsequent ranking. A sensitivity analysis discovers those aspects of an economy that have the highest potential for improving energy sustainability. The model, unlike most existing ones, is nonlinear and uncovers some counterintuitive results such as the higher rankings of Brazil over the USA and Canada. Such results are explained by the high performance of Brazil in the area of energy security and the low scores of the USA and Canada in generation, consumption, and environmental aspects of energy.http://creativecommons.org/licenses/by/4.0/Operational Research - An International Journal2131845–1885 Grigoroudis Evangelos Γρηγορουδης Ευαγγελος Kouikoglou Vasilis Κουϊκογλου Βασιλης Phillis Yannis Φιλλης Ιωαννης Kanellos Fotios Κανελλος Φωτιος Springer Fuzzy evaluation Energy sustainability Indicators Ranking Sensitivity analysis