Stress of Estuarine Cooling

FIGURE 8.7 Energy circuit diagram showing alternative choices for treating thermal pollution from cooling water. Using the estuary for cooling drains much less energy from the entire system than using a cooling tower, and therefore it is the optimal choice for treatment from the perspective of emergy analysis. (From Odum, H. T., W. Kemp, M. Sell, W. Boynton, and M. Lehman. 1977. Environmental Management. 1:297. Springer-Verlag GmbH & Co. KG, Heidelberg, Germany. With permission.)

While the results of emergy analysis from Table 8.7 are consistent with the results from traditional economic analysis (Table 8.1), surprises do occur when emergy analysis is applied. Figure 8.7 illustrates a case for alternative methods of treating thermal pollution from a power plant (H. T. Odum et al., 1977b). Water can be cooled by either discharging it into an estuary or by passing it through constructed cooling towers. Both alternatives are evaluated on the diagram in terms of the emergy: for estuarine discharge the environmental impact is quantified, and for the cooling towers the total cost of construction and operation is shown. The results indicate a relatively small environmental impact (3.4 x 109 fossil fuel equivalents) due to thermal pollution vs. a larger load put on the economy by the cooling tower (276 x 109 fossil fuel equivalents), which causes more environmental impact elsewhere. This is consistent with the nature of thermal pollution, which is not highly disruptive to natural systems, especially in comparison with other kinds of pollution. The best choice then may be to discharge the heated water into the natural estuary even though intuition based on environmentalism might suggest that the cooling towers be built in order to avoid any impact to the environment.

The examples mentioned above are just a small sample of the set of problems and issues that can be addressed with emergy analysis (H. T. Odum, 1996). However, difficulties arise from several directions when attempting to implement emergy analysis for public policy. It is a radical new form of economics because it is based on a completely different currency than humans are familiar with. Emergy analysis represents a kind of physical theory of value rather than a social theory of value, which seems to make it objectionable to some people. Many problems arise because this currency is a physical quantity (i.e., a form of energy) rather than an information marker (i.e., money). Part of the problem also is that existing fields such as physics have other ideas of energy which easily get confused with emergy. Exergy is one example (Jorgenson, 1982, 2000), which is based on a form of mechanical energy. Unfortunately, people unfamiliar with these fields and concepts quickly get confused and turn away from the approach.

Major disagreements exist between emergy analysis and conventional economics (Lavine and Butler, 1981). In large part the disagreement concerns the issue of accounting for both human-centered and ecosystem-centered values. Conventional economics does not do this completely, even with various kinds of adjustments mentioned earlier; emergy analysis does, at least theoretically. This goal is achieved in emergy analysis by utilizing a quantity, emergy, which can be calculated for both human-centered and ecosystem-centered quantities, making it a "common denominator." Conventional economics is computationally sophisticated enough to account for both these quantities, but it philosophically denies that certain kinds of values exist (such as fishes in Figure 8.3). The philosophy and analytical techniques of conventional economics evolved when human populations were at low densities and the ecological life-support system seemed limitless. Under these conditions it was possible, and it even made sense, to exclude certain things from the value system. Thus, the ecological life-support system was taken for granted, and it was assumed that it didn't need to be accounted for. As populations grew, however, the environment became more important to humans and new approaches have evolved to recognize this importance, sometimes through accounting techniques with conventional economics and at other times through social instruments such as regulations and public policies. However, even though the human-environment relationship has changed over time, the philosophical basis of conventional economics has not changed, only the details of some of the accounting techniques. Thus, there may always be disagreement between those who believe in conventional economics and those who believe in emergy analysis because of the philosophical differences between the approaches.

Should society as a whole question the accounting systems used for public policy? Which of the different approaches (conventional economics, ecological economics, emergy analysis) is correct and should be used by society as a guide for making decisions? Is it just a matter of personal preference or belief? The answers to these questions are very important, but they are beyond the scope of this text. However, because ecological engineering involves systems of both man and nature, the more holistic approaches seem to be necessary and appropriate for evaluation, assessment, and design activities.

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