GesamtEmergy

GesamtEmergy, or total emergy, is a concept used in emergy analysis to denote the total amount of emergy required to produce a good, service, or system. Emergy is a measure of the energy memory embedded in something, representing the amount of energy from the past that has flowed into a product or process. It is expressed in emergy units, typically solar emjoules (sej). The idea is that every input to a system—materials, energy flows, labor, capital services, and environmental inputs—has an emergy value based on the transformity of that input, the amount of emergy needed to make or provide it. The GesamtEmergy of a product or process is the sum of all these emergy values.

Calculation and interpretation are central to the concept. To obtain GesamtEmergy, each input is quantified and converted to emergy by multiplying its quantity by the input’s transformity, then all contributions are added. The total can be further divided into renewable and nonrenewable components, which helps analysts compare the energy memory requirements of alternatives. Emergy-based indicators, such as Emergy Yield Ratio, Environmental Loading Ratio, and Emergy Sustainability Index, are sometimes derived from total emergy to assess efficiency, pressure on the environment, and relative sustainability.

Applications and limitations are noted in the literature. GesamtEmergy is used in environmental planning, resource accounting, and sustainability assessments to compare products, processes, and systems from an energy-memory perspective. However, the approach depends on chosen transformities and system boundaries, which can introduce subjectivity and data demands. Critics point to uncertainties in transformities and to questions about aggregation and interpretation, while proponents view emergy as a comprehensive framework for evaluating the energetic and ecological prerequisites of human activities.

See also: Emergy, Emergy analysis, H. T. Odum.