Emergy analysis is an energy-based approach that quantifies emergy, which is the total energy required to produce a product or material flow, through all processes and transformations that may be involved and also known as embodied energy. Total energy is reported in a single, consistent unit – Emergy Joule. This approach allows for quantification of all of the embedded energy of products.

The use of emergy was first described by Odum (1996). Uptake of this method at an urban level has been limited, and most of the case studies are geographically bound to Asia, with the majority of the work being undertaken in Chinese cities.

The term emergy synthesis is also used to describe the use of a series of indices to understand the observed emergy patterns. “Emergy synthesis combines principles from general systems theory, thermodynamics, and systems ecology to account for the total environmental resources contributed for the generation of a product or a service” (Odum 1988 in Huang and Chen 2009, 78). Sometimes this kind of work is called an emergy evaluation. In this report, all of this work will be grouped under the single term emergy analysis.

In order to provide environmental impact insights, a number of hybrid approaches (e.g. MFA-Emergy and Emergy-LCA) have been introduced.