William
McDonough was the keynote speaker for the opening plenary for
this year's GreenBuild
conference. Among other things, he spoke about the “Waste
Equals
Food”
concept. He showed a beautiful scenic picture of a mountain terraced
with rice paddies. He explained that the local people had been
farming that land continuously for five thousand years and that they
might know a thing or two about sustainable agriculture. And then
the kicker.... He said when visiting for dinner in that part of the
world it is considered impolite to leave without “leaving a
deposit” because that would mean taking some of the families
nutritional resources away.
Yesterday I attended a “Principles of
Sustainability” class at the New
York Designs business center. The subject of biofuels was
discussed. A bullet point on one slide made the debatable claim that
the fossil fuel inputs to ethanol production are greater than the
energy produced. Another claim was that biofuels are carbon neutral
because the carbon released when the fuel is burned matches the
carbon sequestered during the plants growth. I'm not a farmer, but
I'm not so sure that is true. First, there is the question of the
fossil fuel inputs to the farm. Certainly those must be included in
the carbon equation. Second is the question of where the carbon in
the plant actually comes from. Does it all come from the
photosynthetic
reaction where C02 is converted to O2? Or does some come from the
organic material in the soil where the plant grows?
I conjecture that if the biofuel farmer
is making a profit, then the energy produced must be greater than the
energy inputs. E.g. that the embodied
energy
of the biofuel is closely approximated by the cost of its production.
This cost of production includes the cost of fuel for the tractors
and the oil used to produce the fertilizer. It also includes the
energy required to manufacture and deliver the tractors. The tractor
cost includes the energy used by the steel mill to smelt the ore
which includes the cost of the energy used to mine and transport the
ore to the smelter. And so on down the line.
To push this idea to the limit, I
further conjecture that the cost of labor involved in all these
activities is also driven primarily by energy costs. The farmer,
manufacturer, steel worker and miner are all paid a decent living
allowing them to buy houses, cars, televisions etc. As we have seen
for the tractor all of those things cost as much as their energy
inputs. As these are all commodity workers, their incomes are pushed
by our free capitalist market place to a level that avoids spilling
much out of the system, to places like vacations in the Caribbean for
example.
What do these conjectures miss? As
with much of our economy, they miss the costs of environmental
destruction in the extraction of the ore, climate change due to
burning of the fuels and – getting back to William McDonough –
depletion of the soil as we convert topsoil to plants and then to
ethanol and then burn it up leaving just a few green house gases and
soot.
Now, I'm not claiming to be an expert
in any of these subjects. I just want to point out that simple
sounding statements such as “biofuels are carbon neutral” are not
really so simple. There are a lot of open questions about
sustainable
farming and how to do it. When biofuels come into the picture,
when the farm products are burned and sent into the atmosphere, when
nutrients do not come back to the soil, when biofuel production
cannot be done organically and is dependent on chemical
fertilizers
which are derived from fossil
fuels
– when all of this happens can biofuels be considered sustainable
at all?
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