This is a part of the Howard T. Odum Collection

The work of Howard Odum generated an entire lexicon of terms that helped communicate his ideas to the world. Some terms, like energy and power, were drawn from existing disciplines but were used in new ways. Other terms such as emergy, energy hierarchy, net energy, and maximum power were new terms that Odum, his students, and his colleagues defined. This glossary defines the most important of these terms and provides some context for how they were used. -- Cutler J. Cleveland

An expression of all the energy and material resources used in the work processes that generate a product or service, calculated in units of one form of energy. In the early 1970’s Odum argued that traditional methods of measuring energy did not account for the “quality” of different forms of energy (e.g. sunlight, versus fossil fuels or electricity). Odum and his colleagues began using sunlight as the base to evaluate all other forms of energy, reasoning that, all other forms are nothing more than concentrated sunlight. David Scienceman, an Australian colleague of Odum’s, first coined the term "emergy." Odum believed that emergy was a universal measure of the work of nature and society made on a common basis and therefore a measure of the environmental support to any process in the biosphere.
To see the full encyclopedia article on emergy: click here