A systems approach to assessing the sustainability of hybrid community energy systems.
Date
2014-09-01
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
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. This thesis develops 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 of an energy system is determined by normalization, weighting, and
aggregation of sustainability indicators. Indicators are normalized relative to sustainable
threshold values and weighted based on time, space, and receptor (i.e., human or
ecosystem impacts) criteria. Aggregation yields an ISI between zero and one, where one
represents a sustainable system. The ISI is calculated for several different case studies
spanning a range of fossil- and renewable-based energy systems. Each is designed as a
stand-alone system to meet the energy needs of a small community in Southern
Ontario. The analysis shows that of the various alternatives, a solar-photovoltaichydrogen
system has the best ISI, which ranges from 0.65-0.90 and is a 4-25%
improvement over the reference, gas-fired system. For the solar-photovoltaic-hydrogen
system and many others, climate change and ozone layer depletion indicators have the
strongest effect on ISI. Affordability, commercial viability, and land area indicators are
also critical for other energy systems. The ISI 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.
Description
Keywords
Energy system, Index, Life-cycle assessment, Sustainability, Weighting factor