Energy Policy

Les Schaffer schaffer at
Tue Dec 3 07:31:32 MST 2002

Richard Wilson wrote:

> We should convert to ethanol as the main source of fuel for
> automobiles as it is cleaner than gasoline and without taxes &
> subsidy on gasoline, would only be a bit more expensive and would
> help our dieing agriculture sector.

to save Comrade Jones from a heart attack, check out the comments on
ethanol production below (4-th paragraph) ... its been some time since
i studied all these kinds of numbers, would be worth revisiting
ethanol, for example, to see if things are as bad as Rees says.

les schaffer

   Nature 420, 267 - 268 (2002) © Macmillan Publishers Ltd.

   Footprint: our impact on Earth is getting heavier

   Sir - Bjorn Lomborg's comments as reported in your recent News
   story (Nature 419, 656; 2002) betray ignorance of
   ecological-footprint analysis (EFA). This is a method I proposed
   (W. E. Rees Popul. Environ. 24, 15-46; 2002) specifically to assess
   the assertions made by some economists that, because of
   technological advances, the human economy is "dematerializing" or
   "decoupling" from the natural world. If true, this implies that
   modern society is becoming less dependent on nature, and can be
   used to justify further economic growth. If false, the additional
   stress likely to be imposed on the natural world will be

   Certainly, no single index can represent the total human impact on
   the ecosphere. However, EFA is comprehensive enough to show,
   unambiguously, that the human eco-footprint on Earth is steadily
   increasing. Comparative studies (such as the Worldwide Fund for
   Nature's Living Planet Report 2002, criticized by Lomborg) show
   that the most technologically advanced nations are the most energy-
   and material-intensive and have the largest per-capita ecological
   footprints. Hence, the consumer lifestyles of their average
   citizens (and of the wealthy residents of the developing world) are
   the least ecologically sustainable on Earth, and cannot be safely
   extended to humans everywhere.

   Lomborg's ignorance of eco-footprint science is illustrated by his
   claim that it ignores the potential growth in the use of renewable
   resources, and that if the use of such resources increases, the
   2050 footprint would not be as large as projected. The fact is that
   EFA is already largely based on use of renewable resources, with
   the exception of the fossil-fuel (carbon sink) component. A shift
   to exclusive use of renewable energy does not necessarily imply a
   reduction in the eco-footprint.

   Biomass fuels, for example, are likely on thermodynamic grounds
   alone to demand a larger growing area than the amount of land
   needed to provide the energetically equivalent amount of fossil
   energy (via carbon assimilation) today. One proposed 'renewable'
   resource, fuel ethanol production, is not even a net source of
   energy. In the United States, 70% more energy (mostly fossil fuel)
   is consumed in producing a litre of ethanol than is contained in
   the product. Even without counting the energy cost of the
   fermentation and distillation process, or the carbon-sink footprint
   of the fossil fuel used to grow the maize feedstock, the average US
   automobile would require 4.4 hectares of cropland to provide its
   annual fuel requirements. (This whopping -- but only partial -- fuel
   eco-footprint is about seven times the cropland needed annually to
   feed one person in the United States.) To run all US cars on
   ethanol would require an area of cropland equivalent to nearly the
   total US land area. More generally, the United States uses 85% more
   fossil energy each year than the total energy captured by all its
   plant biomass over the same period. Clearly, regardless of the
   efficiency of the conversion technology, there is no possibility of
   renewable biomass substituting, joule for joule, for fossil fuel.

   The much-touted solar alternatives may not fare much
   better. Although the solar flux represents a vast flow of potential
   energy, various analysts argue, from both thermodynamic principles
   and empirical data, that humanity faces enormous technological
   obstacles in converting this flow into the energetic equivalent of
   contemporary fossil-fuel use.

   In the light of such data and the implicit uncertainty about
   prospects for sustainability, Lomborg's "sceptical challenge" to
   the ecological footprint concept falls flat. EFA may be static, but
   this does not invalidate estimates of future footprints based on
   reasonable assumptions about technological development. Dynamic
   modelling is just as vulnerable to implicit error in this regard.

   William E. Rees

   School of Community and Regional Planning, University of British

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