Emergy accounting: principles and application for environmental assessment of agricultural and animal production systems

Abstract

Emergy is defined as the direct and indirect energy available to make a product or a service. Emergy accounting is a quantitative technique that determines non-monetary and monetary values of resources, services and products in a common unit: solar Emergy. This method appears suitable to assess agroecosystems and identify key factors for designing more sustainable systems. This article discusses the concept of Emergy through the definition of transformity, energy-system diagrams and several Emergy indicators. These concepts are explained through an example of a fish-farming system assessment. Finally, the article underlines the possible applications of emergy accounting to agricultural systems, in particular animal production.