1. Sustainability Assessment of Hybrid Community Energy Systems

The goal to achieve a sustainable society that will endure over the long term is generally regarded as a positive evolutionary course. One of the challenges with this goal is developing a quantitative assessment of the sustainability of a system. Despite the different measures available in the literature, a standard and universally accepted index for assessing sustainability does not yet exist. Here, we develop a novel integrated sustainability index (ISI) for energy systems that considers critical multidimensional sustainability criteria. The originality of this new index is that it incorporates fundamental thermodynamic, economic, and environmental constraints to combine indicators from multiple dimensions into a single-score evaluation of sustainability. The index is therefore unique because it can assess sustainability relative to an ideal reference state instead of being limited to ranking systems via relative assessments. The ISI is applied to a stand-alone solar-PV-battery system designed to meet the needs of a small community in Southern Ontario. The ISI of the system ranges from 0.52 to 0.66, where one is considered to be a sustainable system. The weighting factors associated with critical economic and global environmental criteria have the greatest effect on the ISI. This index is expected to prove useful as a high-level, multi-criteria decision analysis tool for understanding and fostering sustainable energy systems, alone or in concert with other approaches.