Sustainability Assessment of Solar Technologies Based on Linguistic Information

The leading role in the decision-making process is generally assigned to the decision maker who evaluates the various alternatives and ranks them. In some circumstances the decision is based on the use of different types of information often affected by uncertainty; thus the decision maker is not able to produce all the information necessary to make a strictly rational choice. In many cases the information can be expressed only by using linguistic labels, e.g. “very low”, “medium”, “high”, “fair”, “very high”, etc. It is not easy to precisely quantify the rating of each alternative and precision-based methods are often inadequate. Vagueness results when language is used, whether professional or not, to describe the observation or to measure the result of an experiment. This happens particularly when it is necessary to work with experts’ opinions which are translated into linguistic expressions. The use of fuzzy set theory has yielded very good results for modelling qualitative information because of their ability to handle the impreciseness that is common in rating alternatives. In this chapter a modified multicriteria method (F-PROMETHEE) that uses fuzzy sets is proposed to handle linguistic information in comparing a set of solar energy technologies using only linguistic variables.