Environmental Engineering Reference
In-Depth Information
improved resource allocation and economies of scale.
Ayres, Ayres, and Warr (2003) hypothesized that most
of Solow's residual may be accounted for by thermody-
namic efficiency improvements in the production of pri-
mary work (and, where measurable, of secondary work).
Howard T. Odum found all theoretical or highly ag-
gregate approaches to energy-based valuation fundamen-
tally mistaken because they exclude solar radiation as the
initial universal input and do not convert different energy
flows to equivalent energy costs. In order to carry out
consistent and complete net energy analyses he proposed
the use of energy quality (concentration) factors or trans-
formation ratios for a variety of biospheric and anthro-
pogenic inputs (Odum 1973; 1983). During the early
1980s the ratios acquired both a new name, solar trans-
formities, and new units, solar emergy (embodied en-
ergy), or solar emjoules (sej), per unit of energy, sej/J
(Odum 1988). Odum pursued these valuations for the
rest of his life (Odum 1996; 2000).
The reasoning behind exergy or emergy valuations is
intuitively appealing. Energy is the only unsubstitutable
and unrecyclable input into every human activity, and as
such it is the ultimate limiting factor of development.
Fossil-fueled civilization relies on energies whose supplies
are finite. Consequently, the energy theory of value, best
applied through net energy analysis, appears to be the
most fundamental and most revealing approach to assess-
ing our endeavors as well as our prospects. Critical exam-
ination shows many weaknesses with this reasoning and
many problems with the execution of the idea. On the
most general level, one must agree with Rose (1986)
that all single-item theories of value suffer from selective
inattention to the complexity of civilizations and to
the interconnectedness of things, and hence no single-
variable valuation can be satisfactory.
As for energy's professed uniqueness, there were other
such claims on behalf of land among eighteenth-century
physiocrats, and on behalf of labor among Marxists. Is
energy different? Costanza (1980), while admitting that
energy valuation could have parallels in other theories of
value, maintained that no one would seriously suggest
that labor can create sunlight. But neither would anyone
seriously suggest that the Earth's biosphere could func-
tion without relying on the geotectonic recycling of
crustal elements—for both its fundamental biochemical
functions (P in ATP, S in proteins, Co and Mo in nitro-
genase) and structures (Si in plant stems, Ca in animal
skeletons)—whose prime mover has nothing to do with
sunlight (see section 2.5).
And surely time cannot be treated as a derivative of en-
ergy. Indian swamis may be oblivious to its existence, but
in modern Western civilization it is an obviously scarce
entity, and its valuation and management very often take
clear precedence over the levels and efficiencies of energy
use (Spreng 1978). Even the gurus of eco-economics
travel by airplane; they, too, value time and do not base
all their choices on energy valuations. Such trade-offs
are ubiquitous, and many of them have come to define
the very fabric of modern society, although we may no
longer think of them that way: a refrigerator is primarily
a time-saving device, as is a lightbulb.
Treating all nonenergy entities as energy transforms,
and pricing everything according to embodied energy
content, is forcing multifaceted reality into one-
dimensional confines. This approach is clearly inappropri-
ate in a world where geophysical, biophysical, technical,
social, and moral concerns are intertwined. Management
of a civilization is far from being merely a matter of en-
ergy conversions. Nor is any valuation just a matter of
supply. In the real world there are always many relative
