10. A Fuzzy Paradigm for the Sustainability Evaluation of Energy Systems

A vital part of sustainable development is the provision of adequate, reliable, and affordable energy, in conformity with social and environmental requirements. Energy is one of the most crucial factors that power modern economies subject to a volatility in price and supply, while at the same time it is responsible for major environmental consequences with global warming topping the list. In this chapter we develop a model that provides a general mechanism to measure the sustainability of energy sectors. Sustainability is an inherently vague concept, and for this reason the model uses fuzzy logic, which has the ability to deal with such an ambiguous, complex, and polymorphous concept. The proposed model follows the principles of SAFE (Sustainability Assessment by Fuzzy Evaluation), a model for the numerical assessment of sustainability. To consider the cumulative effects of past policies, we use exponential smoothing on sustainability data, while an imputation procedure is applied in order to overcome the problem of missing values. The model is applied to a large set of countries, which are ranked according to their sustainable energy development.