The well-known rules of Emergy Algebra, originally formulated in steady state conditions, are reconsidered and analyzed from a dynamic point of view. In such a sense the paper points out their corresponding differential bases. The latter, in turn, represent the preferential guide to recognize their most profound physical meaning. However, for the sake of completeness, a possible generalization ...

This article presents a general methodology for modeling complex dynamic systems, focusing on sustainability properties that emerge from tracking energy flows. We adopt the embodied energy (emergy) concept that traces all energy transformations required for running a process. Energy can therefore be studied in terms of all energy previously invested up to the primary sources, and sustainability...

This paper evaluates in emergy terms the resource use and environmental performance of the Italian agricultural sector across levels, from local scale (olive, lemon and grape farms), through regional scale (Campania region) up to the national scale (whole Italy). The evolution over time (from 1985 to 2006) is also investigated to take into account how the demand for environmental support change...

Energy Systems Theory (EST) provides a framework for understanding and interpreting sustainability. EST implies that "what is sustainable" for a system at any given level of organization is determined by the cycles of change originating in the next larger system and within the system of concern. The pulsing paradigm explains the ubiquitous cycles of change that apparently govern ecosystems, rat...

Accurate and sufficient information on unit emergy values (UEVs) is very fundamental for emergy calculations and is also essential for the broad acceptance, application and further development of the emergy method. As an extension of matrix methods, an input-output model based framework was built in this paper, for estimating transformity (UEV) of products and services of a certain economy. The...

Emergy methodology questions were raised during a case study where a Sugar factory effluent were treated in a pond system in the Lake Victoria watershed, and evaluated from a performance, cost and resource use perspective. This paper focus on the methodological questions, which were the following: (1) how should the emergy systems diagram be drawn when dealing with a system that is in the recyc...

The concern about soil quality has increased, since its use and intense mobilization may decreased its ability to keep a biological and sustainable production. However, since soil quality cannot be comprehensively measured by a single indicator, emergy synthesis rises as an alternative to assess this issue. This study aimed to present a comparative method for soil quality vis-a-vis the resource...

Conventional ranching in Chiapas, Mexico includes a yearly pasture burn and agrochemical use that decreases the biodiversity and forest cover of ranch lands. Ranchers, self-described members of a “club” in the Fraylesca region of Chiapas, Mexico, have bucked convention and eliminated burns and agrochemicals from their systems after decades of use because they believed that the land and their pr...

The measure of value called emergy is used to evaluate the flows of energy and resources that sustain the biosphere including the economy of humans. A donor system of value based on solar emergy required to produce things is suggested as the only means of reversing the logic trap inherent in economic valuation, which suggests that value stems only from utilization by humans. The stocks of natur...

The region of Saemangeum for this study is influenced by two major rivers, Dongin and Mankyung. Currently, a 33km long seawall has been constructed for the purpose of reclamation of 283km2 land area and fresh water reservoir area of 118km2 for the major national internal development project, planned for its completion by 2030. The Saemangeum provides an optimal location for tidal power generati...