Energy and Water Sustainability: What do They Mean and Can We Know When We Achieved Them?

Abstract

The word "sustainability" has been applied to resources such as energy and water, in addition to products, processes, urban infrastructure such as a city, or a quasi-natural infrastructure such as an eco-system. While there have been reasonable attempts made to evaluate the sustainability status of product and process systems from economic, environmental and societal impacts perspectives, no such systematic or rigorous analysis has been attempted for water and energy as resources, or water and energy supply systems. This discussion covers the essential sustainability concerns of water and energy systems and provides some thoughts on how one evaluates sustainability status and pathways for improvements.