Monday, January 17, 2011
Emergy is not the new Money
Emergy analysis aims to document and compare the amount of energy required to produce different products. In comparison to Embodied Energy analysis, which measures just human inputs of energy, Emergy analysis measures both natural and human energy inputs. The laudable goal is to put all calculations in the same currency so that everything can be compared. However, emergy is an impossible concept and, in the end, really just weird.
First, it is weird economics. In fact, it is Marxist economics because Emergy, like Marxism, seeks to go beyond the capitalist system that assigns value based on demand to an alternative system based on supply. But then Emergy turns around and assigns emergy to dollars, a blatant contradiction. Also, emergy is not able to account for opportunity costs. For example, there is still no way to value the salmon that would have lived had it not been for the dam that destroyed their spawning grounds.
Second, it is a weird way of valuing raw resources (inputs). Putting everything in terms of solar energy makes some sense, but not when a dubious logic is used to convert rain and wind into solar equivalents, let alone when metal ores are assigned an arbitrary emergy. The urge to put everything into a hegemonic coinage is as old as the simplifying instinct, and as faulty. Everything can't be reduced to solar energy. Sustainability needs a more adaptive system and a more adaptive framework to ask questions.
Third, it has weird system diagrams (see above). While they look cool at first, one quickly realizes their myriad failings by comparing emergy diagrams to contemporaneous dynamic stock-and-flow modeling software like Stella. Also, emergy puts the controlling forces in the same format as the flows of energy, confusing both.
Fourth, it is weird ecology. The idea of "resources required" for a certain product seems to assume that the resources are "used up" in making that product, but ecosystems don't work that way. The grass that the cow eats might otherwise have died and decomposed, or if a cow eats all the grass in the lot it may create better habitat for some bird species. Presence and absence, especially of niches, are not physical qualities of a habitat. An emergy-type analysis applied to fishing suggests that eating one tuna is equivalent to eating 1,000 sardines, but that is only true if you have to farm the sardines to feed a farmed tuna. In the wild, that tuna has already eaten 1,000 sardines, whether you now eat the tuna or not. In fact, your eating the tuna may spare the next 1,000 sardines from being eaten! While it may be desirable to spare the tuna for other reasons, emergy fails any.
Fifth, it is a weird idea of sustainability. Emergy explicitly doesn't want to "double count" sun and wind, yet a smart farmer could do just that by harvesting wind energy and solar energy. Emergy doesn't do a good job of figuring out what is sustainable versus what isn't: it provides a plethora of weird ratios for calculating "Environmental Yield Ratio" and other indices of sustainability, but these ratios are all based on predetermined categorization of whether a given input is sustainable or not, thus assuming the very thing they seek to prove.
To put everything in the same system to compare everything comes from a good motivation but the conclusions end up being trivial. In my humble opinion, it may be impossible to accurately compare fish and electricity and sedimentation in terms of the energy that went in to them. Weirdly, dollars are still best.