Emergy - History

History

The theoretical and conceptual basis for the emergy methodology is grounded in thermodynamics, general system theory and systems ecology. Evolution of the theory over the first thirty years was documented by H.T Odum in Environmental Accounting and in the volume edited by C.A.S. Hall titled Maximum Power. Beginning in the 1950s Odum recognized principles of energy quality as an outgrowth of his investigations and simulation modeling of ecosystems of humans and nature (e.g. Silver Springs, Florida; Eniwetok atoll in the south Pacific; Galveston Bay, Texas and Puerto Rican rainforests, amongst others) where energies of many different forms at many different scales were observed. His investigations about energy flows in ecosystems and the differences in the work potential of sunlight, fresh water currents, wind and ocean currents and even fossil fuels made it clear that when two or more different energy sources drive a system they cannot be added without first converting them to a common measure that accounts for their differences in quality. This led to the concept of "energy of one kind" as a common denominator with the name "energy cost". The first formal recognition of energy quality was in Odum's book Environment Power and Society

Beginning in the last century man began to develop an entirely new basis for power with the use of coal, oil, and other stored-energy sources to supplement solar energy. Concentrated inputs of power whose accumulation had been the work of billions of acres of solar energy, became available for manipulation by man.

The first formal statement of what would later be termed emergy was in 1973:

Energy is measured by calories, btu’s, kilowatthours, and other intraconvertable units, but energy has a scale of quality which is not indicated by these measures. The ability to do work for man depends on the energy quality and quantity and this is measurable by the amount of energy of a lower quality grade required to develop the higher grade. The scale of energy goes from dilute sunlight up to plant matter, to coal, from coal to oil, to electricity and up to the high quality efforts of computer and human information processing.

It appears that the first quantitative evaluation of energy quality was in 1975 in the acceptance speech for the Prize Institute la Vie in Paris, which contained a table of “Energy Quality Factors”, or the kilocalories of sunlight energy required to make a kilocalorie of a higher quality energy. This is the first mention of the energy hierarchy principle which stated that “energy quality is measured by the energy used in the transformations” from one type of energy to the next. These energy quality factors, were placed on a fossil fuel basis and called "Fossil Fuel Work Equivalents (FFWE) and the quality of energies were measured based on a fossil fuel standard with rough equivalents of 1 kilocalorie of fossil fuel equal to 2000 kilocalories of sunlight. "Energy quality ratios" were computed by evaluating the quantity of energy in a transformation process to make a new form and were then used to convert different forms of energy to a common form, in this case fossil fuel equivalents. FFWE's were replaced with Coal equivalents (CE) and by 1977, the system of evaluating quality was placed on a solar basis and termed solar equivalents (SE).

The term "embodied energy" was used for a time in the early 1980s to refer to energy quality differences in terms of their costs of generation, and a ratio called a “quality factor” for the calories (or joules) of one kind of energy required to make those of another. However, since the term embodied energy was used by other groups who were evaluating the fossil fuel energy required to generate products and were not including all energies or using the concept to imply quality, embodied energy was dropped in favor of “embodied solar calories” and the quality factors became known as "transformation ratios". "Embodied energy" was abandoned altogether in 1986 when David Scienceman, a visiting scholar at the University of Florida from Australia, suggested the term “emergy” and "emjoule" or "emcalorie" as the unit of measure to distinguish emergy units from units of available energy. The term transformation ratio was shortened to transformity in about the same time. It is important to note that throughout this twenty years the baseline or the basis for evaluating forms of energy and resources shifted from organic matter, to fossil fuels and finally to solar energy.

Between 1986 and today, the emergy methodology has continued to develop as the community of scientists has expanded and as new applied research into combined systems of humans and nature has presented new conceptual and theoretical questions. The maturing of the emergy methodology has resulted in more rigorous definitions of terms and nomenclature and refinement of the methods of calculating transformities. There is now an International Society for the Advancement of Emergy Research and a biennial International Conference held on the campus of the University of Florida.

The following table is a chronology of the evolution of the emergy methodology and nomenclature providing a brief insight into the development of the concept.