Energy Diagrams Illustrate Energy Laws Organizing Systems
Much of modern science is focused on a study of the parts and not the whole. Many of our tools such as microscopes and statistics attempt to focus our gaze on smaller and smaller pieces of the puzzle, learning “more and more about less and less, until we know everything about nothing” (source attributed to many people, including Einstein and Schopenhauer). This describes much of modern reductionist science. But . . .
“If the bewildering complexity of human knowledge developed in the twentieth century is to be retained and well used, unifying concepts are needed to consolidate the understanding of systems of many kinds and to simplify the teaching of general principles” (Odum, 1994, p. ix).
Scientists need holistic views to counteract the tendency to focus narrowly. We need generalists in addition to our specialists. And we need people who can look at our problems at a larger scale; Einstein said that we cannot solve problems from the same consciousness that created the problems. We must learn to see the world anew, from a larger scale to see a complete picture of the processes involved.
Energy can unify and simplify the understanding of complex systems. Energy systems diagrams represent the passage of energy through systems at various scales. Energy is a part of all storages, and flows of energy are a part of all processes. Complex energy relationships exist at all scales, so energy diagrams aggregate key structures, processes and flows within the time and space boundaries of a model. These diagrams can simplify the representation of key parts and relationships of complex systems in energy terms. The models can be quantified to represent the systems and then operationalized to simulate and explore system behavior. The calculus embedded in the diagrams supports a durable science that reflects the energetic principles and the contributions of higher and lower levels of nature to economic systems. Energy diagrams give the lenses for the macroscope through which we view the “3 Es”, energy, the environment, and economies.
Historically, Odum developed the Energy Systems language beginning in the 1950s to explain energy flows through ecosystems as an analogy to voltage in electrical circuits. This allowed the expression of the first and second thermodynamic laws, feedback, and eventually the principle of maximum power. His Sankey diagrams in the 1950s evolved into Energy Circuit language in the 1960s, which was then translated mathematically on early analog computers for simulation modeling. By the mid to late 1970s, the language and math supporting the diagrams had evolved onto digital computers with Basic programming and then Extend in the early 1990s. Finally in the late 1990s the models evolved to include the math of emergy and transformity (Brown, 2004).
Mark T. Brown (2004) describes diagramming. In order to depict a system, one starts by listing:
. . . its energy, material and information sources . . . the “driving energies” as Odum labeled them. Next the components are listed and then the state variables, and finally the outputs . . . . Each symbol is rigorously and mathematically defined. By drawing a diagram one, in essence, is writing equations that describe the system under study. In fact, Odum suggested that the first step in simulation modeling should be to draw a diagram of the system. The equations describing relationships and processes of the system then emerge, simply, from the diagram. Thinking on the behavior and structure of a system is done in the diagramming (Brown, 2004).
The language used in emergy diagrams is described below. The last two links below represent complete short courses on how to diagram ecosystems and carry out emergy evaluations.
- Energy Loss-heat sinks, or energy that is dispersed and no longer usable, such as the energy in sunlight after it is used in photosynthesis, or the metabolic heat passing out of animals. Heat sinks are attached to storage tanks, interactions, producers, consumers, and switching symbols
- Sources-energies that accompany each of the resources used by the ecosystems such as sun, winds, tidal exchanges, waves on the beaches, rains, seeds brought in by wind and birds
- Storage-a tank or stock where energy is stored. Examples are resources such as forest biomass, soil, organic matter, groundwater, and sand in beach dunes
- Interaction-a process which combines different types of energy flows or flows of materials
- Switch-a process which turns on and off, such as starting and stopping fire, pollination of flowers, and closing of fishing season
- Generic Flow-an energy pathway or flow of unidirectional energy, often with a flow of materials
- Consumption-a consumer unit which uses the products from producers, like insects, cattle, micro-organisms, humans, and cities
- Production-a producer unit which makes products from energy and raw materials, such as trees, grass, crops, or factories
- Self-Limiter-an internal cycle limits the output when the input force is increased, causing diminishing returns on output, such as chlorophyll limits of recycling nutrients in photosynthesis
- Transaction-a business exchange of money for energy, materials, or services
- Box (not shown)-a miscellaneous symbol for subsystems such as soil subsystems in a diagram of a forest, or a fishing business in a diagram of an estuary
Here is another basic explanation of what the diagrams mean, by Dr. Ben Fusaro
Introductory 20 minute Doculecture by Greg Moller of University of Idaho
More advanced introduction to systems diagrams from Emergy Short Course (Dr. Dan Campbell)