DOI
https://doi.org/10.1016/j.jenvman.2020.110464

Summary
This paper critically reviews the academic literature on the clean, affordable and secure supply of energy focusing on methods of assessments, measures of sustainability and emerging issues in the literature. The social, economic and environmental impacts of various energy production systems of 128 peer-reviewed journal articles, covering a 20-year period, ending 2018, were examined.
The first section of this paper provides a brief overview of the concept of sustainability (definition and dimensions), systems thinking and other research themes reviewed in this study.
The review methodology involved a three-stage procedure comprising literature generation, screening (identification of the relevant literature) and evaluation.
The Descriptive and Network analysis used are briefly described. The mapping and cluster analysis using VOSviewer (version 1.6.9) were aimed at identifying the main research issues in the sustainable energy production research domain and how these topics relate to each other.
The main themes reviewed are:
• the nature of assessment approaches used in examining the sustainability of the energy generation systems
• measures of sustainability (the dimensions of sustainability and weighting of dimensions)
• emerging issues (Modelling weak and strong sustainability and systems thinking)
From the literature reviewed, a number of research gaps that exist within the sustainable energy production systems research domain are highlighted:
• It seems that researches tend to mainly focus on quantitative methods that provide some form of composite indices to study the level and nature of sustainability of units under investigation.
• Current models used for sustainability problems of energy systems do not seem to effectively model the practical implications of the integration of the various dimensions.
• Although systems thinking to sustainability assessment offer a useful perspective for modeling the interconnectedness, relationships and interactions, which are key underlining principles of sustainability, systems thinking to sustainability assessment seem to be relegated to mainly life cycle assessment of environmental impact.
• There is a need for the development of models that can better assess systems based on these sustainability perspectives.
• There is no consensus on the importance of the various dimensions of sustainability, studies tend to be subjective in their weighting of dimensions

Relevance for Complex Systems Knowledge
This paper deals with sustainability and system thinking. The authors examine in this survey the extent to which system thinking has been used in sustainability assessment literature of energy generation.

Point of Strength
The point if strength of this article is the highlighting of the research gaps in sustainable energy production systems research and the provided recommendations for setting a research agenda.