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Emergy: you spelled energy wrong!

EMergy–yes, that word is spelled correctly. Emergy with an EM, means the Energy Memory of something. What is Emergy, and how do I learn more about it? I have been getting requests for suggested readings about EMergy–so here is a brief explanation and some suggested links.

Science proposes to describe, explain, predict, and control. But when we talk about global problems of the biosphere, science often fails in explanation, prediction, and problem-solving. Many scientific disciplines have reduced themselves into specialized, competitive silos, protected from each other by separate terminology and reductionist theories. The lenses through which many scientists view the world are microscopic in nature, focusing on analysis and application, using statistical tools that break things down into smaller and smaller pieces. This focus makes it difficult to even define the problems, much less find solutions. While analysis is a useful and important subset of the overall process, synthesis and evaluation of policies requires using an instrument such as a macroscope to view the world from a systemic perspective. Our lack of synthesis prevents us from seeing and evaluating the relationships, processes and structures inherent in the whole. And our grasp of the holistic big picture is what frames our view of society’s trajectory and the problems society faces.

How does one find a coherent way to grasp the big picture of how man exists on this planet? If we use a macroscope to analyze energy flows using Emergy Synthesis, then we can capture the essence of complex, global systems, since a continuous flow of energy is the central issue to maintaining our complex civilization (or not). Understanding the nature of our energy basis is essential to understanding where we are headed as a civilization.

Empower Basis MTB-Lecture 3

Empower Basis MTB-Lecture 3

Originally H.T. Odum used the term embodied energy, but he transitioned to the term EMergy, as a short form of Energy Memory.

”Emergy is the available energy of one kind previously used up directly and indirectly to make a product or service. The energy required for the transformations is no longer in the product or service, but energy carries the memory of the availability that was used up. Emergy is a new kind of state variable. The units of energy are defined with the prefix em- (e.g., emcalories, emjoules, emBtus)” (Odum, 2007, p. 69).

How emergy adds up? From MT Brown's slides.

How emergy adds up. From MT Brown’s slides.

Flows of energy carry emergy. The emergy transforms hierarchically in a series of steps in complex systems, in a sort of energetic food chain, from natural systems, on into human economies. This transformation occurs due to the principle of Maximum Power. Over time, the Maximum Power Principle dictates that all systems maximize power intake, energy transformation, and those uses that reinforce production and efficiency. Maximum power creates feedback loops that concentrate and organize energy into increasingly complex systems, as long as the surplus energy is available to create long chains, thus combatting entropy. These long chains of increasingly complex hierarchy are what has created our complex global economy as a result of the vast amounts of fossil fuels we accessed in the 19th and 20th centuries. A series of quotes from the Wikipedia link on Maximum Power Principle elaborates further.

Odum et al. viewed the maximum power theorem as a principle of power-efficiency reciprocity selection with wider application than just electronics. For example Odum saw it in open systems operating on solar energy, like both photovoltaics and photosynthesis (1963, p. 438). Like the maximum power theorem, Odum’s statement of the maximum power principle relies on the notion of ‘matching’, such that high-quality energy maximizes power by matching and amplifying energy (1994, pp. 262, 541): “in surviving designs a matching of high-quality energy with larger amounts of low-quality energy is likely to occur” (1994, p. 260). As with electronic circuits, the resultant rate of energy transformation will be at a maximum at an intermediate power efficiency. In 2006, T.T. Cai, C.L. Montague and J.S. Davis said that, “The maximum power principle is a potential guide to understanding the patterns and processes of ecosystem development and sustainability. The principle predicts the selective persistence of ecosystem designs that capture a previously untapped energy source.” (2006, p. 317). In several texts H.T.Odum gave the Atwood machine as a practical example of the ‘principle’ of maximum power.

Maximum EmPower, then, is the measure of emergy flow up the hierarchy or food chain over time, according to the energetic instigation of organisms attempting to maximize power.

“The energy that was required [to make the product] is no longer a part of the product, but emergy is a property that represents its history and implies its importance. It remains with the product and the product’s products until the available energy is gone. Emergy disappears when the available energy is used up (degraded) (Odum, 2007, p. 69).

Systems organize to increase feedback loops and high quality storages to increase energy flows. Systems also develop exchanges with other systems for needed inputs to grow. The systems match high quality energy with low-quality energy to provide maximum intermediate power efficiency. If energy sources become limiting, systems increase their efficiency as a secondary response (after maximizing power). (MT Brown Lecture 2)

Maximum Empower (from MT Brown Lecture 2)

By using Emergy Synthesis to value things, energies of differing qualities such as sunlight, fuel, electricity, and human service can be put on a common basis by expressing each of them in the emjoules of solar energy that is required to produce them. If solar emergy is the baseline, then the results are commonly reported as solar emjoules (abbreviated seJ). Emergy synthesis is a biophysical approach to measuring human activities that considers the indirect and direct contributions of ecological processes using equivalents of solar energy rather than monetary metrics to consider differences in quality of energy. It approaches valuation from a donor-based or supply side independent of the more usual economic demand-based approach that is dependent on subjective values of willingness to pay. The goal of the method is to capture the contributions of nature in economic evaluations. Advocates of a prosperous way down propose that policy decisions can be more deliberate by basing the decisions on quantitative Emergy Evaluation/Synthesis, with better evaluation of market processes.

Energy quality varies, and not all forms of energy have the same ability to do work, depending on the system and the intensity of energy required. Net energy contributions of any process or object within the economy, including energy production, can be calculated using an Emergy Yield Ratio (EYR) (Odum, 1976, Brown & Ulgiati, 1997).

David Scienceman recently explained the emergence of the word Emergy. In the 1980s, Odum was using the term embodied energy. But Russian scientists appropriated that term for their own theories. So, as was common with Odum’s ideas, Odum had to move on and name his idea something else, as society mainstreamed and modified his ideas. Scienceman explains his linguistic contribution:

I was aware with my background in general physics and engineering of the historical importance of the new words. The word embodied was already in common use to mean storing stuff in a body, or to turn stuff into a body, and then to leave it there. But Odum was referring to embodied energy as stuff stored and then transformed, which was therefore not embodied. I therefore suggested the word Emergy to contrast with and to replace the phrase embodied energy because it uses a different algebra, as does energy and exergy. The photograph below displays most of my thoughts at the time. The photograph introduced the new words Emergy (to contrast with energy); Empower ( a noun, to contrast with ‘to empower’, a verb; Transformity (to quantify energy quality); the phrase Emergy Synthesis to contrast with Energy Analysis; the prefix EM to imply energy memory of anything, such asEmformation, to mean the energy memory of information, and Emmonity to mean the energy memory per money unit. And that was the end of embodied energy (Scienceman, 2012).


David Scienceman, Oct. 1984, CFW, UF

Do you know the emergetic basis for an electric car versus an internal combustion energy car? Do you believe that the US can transition to an information-based society in a low energy world? Do you understand the emergy basis for our society? If not, do you want to know more?

The Emergy bible is Environmental Accounting, but it is pricey, costing $130 US at Amazon. The best place to start is actually the Wiki. Then, Odum’s last book is inexpensive and comprehensive, giving a broad overview of ecosystems thinking. Free online, you can also start here. If you want to read more, here’s an extensive bib, some of which are available as free PDFs. And these series of slide shows of Mark Brown’s are really helpful–look at them in order if you’re still interested. Once you do that, if you’re still interested, try tackling Dan Campbell’s short course.

Since we’re talking about linguistics here, Brian, @TheEmergist coins a new label for Emergy researchers–I like it.

Emergist-/’enərjist/-noun-a person who tries to see everything through an energy hierarchy. Like the carpenter who only had a hammer so everything looked like a nail, the emergist saw a world ruled by energy hierarchies.

Once we view the world through an energy lens, there is no going back. Similarly to the heroes in movies The Matrix and Avatar, once our small-view blinders are off, and we can see the energy flowing through the system, it is as though a whole new way of viewing and interpreting the world opens up. As Frederick Soddy said:

The laws expressing the relations between energy and matter are, however, not solely of importance in pure science. They necessarily come first in order … in the whole record of human experience, and they control, in the last resort, the rise or fall of political systems, the freedom or bondage of nations, the movements of commerce and industry, the origin of wealth and poverty, and the general physical welfare of the race. (Soddy, 1912, pp. 10-11).

Brian has written a nice introduction to the idea of Emergy within information systems. Here is a snippet. You can find the rest of Brian’s post here.

Information systems have two key features. The first is that they take large amounts of energy to create the first copy, but additional copies take significantly less energy to make. This allows for information to spread rapidly. The second is that since information systems take so much energy to create, it is higher in the energy hierarchy and has the ability to massively impact other systems. Further, the more energy that is used to make the specific information system, the larger the impact it has on other information systems. This has important ramifications for how we perceive the impacts of human information systems. It often can appear humanity’s prowess creating technology is endless, because of its ability to work outside the natural DNA/RNA information system (genetics) and how rapidly it spreads while failing to realize there is an initial high energetic cost for information innovation (Brian@TheEmergist).

What do you think? Leave a comment below.

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