APPLYING THERMOECONOMICS TO THE ANALYSIS OF ... - circe

therefore a reduction of biomass resources implies a reduction of required harvest area, or what is the same, more
people could be fed with the same land. Hence, the reduction of biomass requirements per habitant is also a key point in
sustainable developing.
4. CONCLUSIONS
Symbolic thermoeconomics is a general methodology for the thermoeconomic analysis of exergy systems. Its main
objective is the analysis of the cost formation process in energy systems and its interaction with the environment.
The environmental impact associated to each process of the food chain system can be quantified as a cost function,
in terms of natural resources consumption. This example illustrates the capabilities of thermoeconomic analysis to be
applied to macroeconomic environmental systems. In this kind of systems with a high level of aggregation, it is
possible to use as free variables the efficiency of the process or the structural junction ratios. However, in microsystems
such as power plants with a high level of dissagregation, these parameters are mutually dependent.
In the analysis made in this paper it is shown that an animal-based diet requires more energy, land and other natural
resources than a plant-based diet. In fact, the production and processing of meat (and other animal products) has the
largest impact on energy use, water use and land disturbance of all our various consumption activities. A soft change in
the human diet, consuming less meat and supplying the required energy demand with a richer vegetal diet, provides an
important fossil fuel saving and allows feeding more people. Other aspects of thermoeconomics such as the principle of
non-equivalence of the irreversibilities (Kotas, 1984) are also illustrated in this example, showing the importance of
reducing and recycling wastes and improving the efficiency of the last stages of the productive food chain. An
improvement of the food processing can be accomplished by buying locally grown and seasonal products, reducing the
fossil fuel consumption.
The search of a sustainable food system will generate benefits in numerous areas: health, biodiversity, ecological
restoration, energy saving or economic justice. None of these benefits alone may outweigh the apparent sort term gains
of the current destructive system. But the sum of these benefits will make a more sustainable society and will help to
avoid the trap of increasing production and entropy generation at the expense of a more and more degraded earth.
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