Sustainability assessment of energy systems: A novel integrated model

Abstract

This paper introduces a new and comprehensive sustainability assessment model for energy systems. The model follows an integrated approach and explores various disciplines that influence sustainability assessment including energy, exergy, economy, environment, society, technology education, and the size of the energy system. These disciplines are taken into consideration when assessing the sustainability of an energy system in a methodological approach by integrating thermodynamic-based concepts as well as other mathematical models in the assessment of each discipline. An index for each discipline is developed to reflect its degree of influence over the overall sustainability index. Target values are used to normalize the data while various aggregation and weighting methods are used to offset possible subjectivity in the assessment. Aggregation using the weighted geometric mean yields in more precise results than using the weighted arithmetic mean. Furthermore, equal weighting scheme yields in the highest sustainability index scores while the individualist scheme results in the lowest sustainability index scores for the sample case study. Based on the weighted geometric mean, the solar PV system has a low sustainability score of 0.56 using the panel method and a high score of 0.59 using the hierarchist and equal weighting methods. The index with the lowest priority factor according to the panel method is the sizing index with a weight of 0.05. The index with the highest priority factor according to panel method is the environmental friendliness index with a weight of 0.18. The energy and exergy efficiencies of the integrated solar photovoltaic system are 66% and 30% respectively.