emergy
Emergy is a measure of the energy that has been consumed to produce a good or service, expressed in emergy units such as solar emjoules (seJ). Coined by systems ecologist Howard T. Odum in the 1980s, emergy represents the energy memory embedded in materials, products, and ecosystems by converting diverse inputs—solar energy, chemical fuels, labor, and manufactured energy—into a single common unit through transformity values.
Transformity is the emergy per unit of input energy, reflecting the quality or transformative effort required
Emergy analysis yields indicators such as the Emergy Yield Ratio (EYR), the Environmental Loading Ratio (ELR),
Emergy analysis has been applied to compare production systems, natural resources, and urban metabolism, and is