Environmental sustainability and climate changes mitigation are linked with energy efficiency and renewable energy deployment. Whereas, renewable energy exploitation at large scale generation needs high initial investment, which is not achievable in short to medium terms, especially in developing countries. Therefore, energy efficiency measures as a good alternative for environmental sustainability are the researchers' interest to evaluate its potential from individual energy consumers to utilityscale (generation, transmission, and distribution). Referring to literature and the connection between the second law of thermodynamics and environmental impact, environmental effects are reduced due to low energy when energy efficiency increases. Therefore, assuring demanding efficiency, interrelations studies, and impact analysis of influential factors are known exigence. This study draws a thematic perspective that involves an exhaustive investigation, explaining the relationship between exergy, environment, and energy within optimum efficiency requirements. Also, this study deals with indicators and indices in adapt to energy and environmental demand to reveal the underlying fundamental impressing forces regarding efficiency improvement.