permaculture

[Lawrence London <lfljvenaura@gmail.com>]

 Howard Odum and Emergy  (energy memory)

williambraham.net » Environmental Accounting: Waste and Value
http://williambraham.net/?p=64

“Emergy” means waste, it also means value, and so poses a fundamental
question for environmental accounting.

Emergy is Howard Odum’s neologism for embodied energy or energy memory, the
total energy used in the production or preparation of a product or process,
whether natural or artificial. Put the other way, it accounts for all the
energy transformations along the path from the original energy inputs to
the bio-geosphere: sunlight, geothermal heat, and tidal actions from the
moon. Since every energy exchange or transformation involves some waste,
emergy accounts for the all the energy degraded along the way.

For example, tracing the many energy transformations involved in the
production of electricity from coal, beginning with the primeaval sunlight
and plant photosynthesis, the long distillation and compression of those
plants into coal, the mining and transportation, and then combustion of
that coal in a power plant to produce and transmit electricity, results in
an embodied energy of about 160,000 units of energy for each unit of
electricity. If you use that electricity to power a light bulb in a
building, at something like 20% efficiency, then the energy degraded is
800,000 units to make a single unit of light. Compare that to the daylight
that enters through a window, and the embodied energy is something like 10
or a 100 units for each unit of light, depending on windows and atmospheric
condition.

In short, electricity is environmentally expensive because of the many
wasteful steps in its production, but it also means that electricity has
great value. If we look at this from the perspective of efficiency, we
should use energy (or eat food) as low on the chain of transformations as
possible. but if we understand this as a form of wealth, wouldn’t we try to
accumulate it?

The difference seems to be in the difference between an individual ethic,
which seeks the proper fit or efficiency of a particular decision or act,
and a system or population ethic, which seeks to maximize the flow of power
and the multiplicity of cascades of transformation. Fully developed
ecosystems seem to prosper precisely by developing staggering hierarchies
of emergy and niches supporting populations at every level of those energy
transformations. The carnivore at the top of the food chain doesn’t rule
the system, despite the king-of-the-jungle metaphors, but rather is the
symptom or benefactor of a richly complex eco-system.

The question of environmental accounting for human projects begins with the
question of how industrial civilization fits into the total eco-system, and
cannot be reduced to measures of individual proejct efficiencies?Is the
relentless accumulation of wealth and power simply, ecologically
“natural”? Is that civilization destined to follow the boom-and-bust, or
predator-and-prey, cycles typical of every other comples ecosystem, and
should that change our accounting of value?
Tags: Emergy, Odum