Russell McMahon <apptech <at> paradise.net.nz> writes:

> > So what's really messing up the equation is the external fossil 
> > energy
> > needed to get at the biofuel.
> 
> It's not that it's *fossil* energy per se that neds inputting - it's 
> the fact (apparently) that overall the net process loses energy. If 
> you consider biofuel to be an energy transport medium (as hydrogen is) 
> and IF you have sources of energy elsewhere that are net energy 
> positive but not accessible, then the biofuel may be viable (eg a 
> methanol operated car may use solar energy produced in the Simpson (or 
> Sahara) desert.. If though you are looking at the biofuel as being an 
> energy "source" in its own rigjht there appear to be 'problems'.

I keep wondering why the powers that be insist in calculating the energy output
of biofuels with 'fossil energy input'. Obviously the production of a biofuel
would strive to use NO fossil energy. Therefore the energy input must be
calculated in biofuel energy input (as in wood, peat, solar etc).
 
> '> That puts forward the case for nuclear
> > (fission now, hopefully fusion in the future), hydro, wind, solar 
> > etc to
> > do that.
> 
> The arguments are that all of these (except for fusion) are in fact 
> net energy negative and/or not renewable. eg Nuclear fission is 

Look, all energy sources are net negative. 'Renewable' simply means that He3 can
be imported from offearth or that sun energy can be used in some form to
'replenish' the resources. All the bullshit statements about net 'negative' are
point-of-view euphemistical sofisms. ALL energy sources are net 'negative'
because by using them one simply taps off a little bit from the increase of
entropy that occurs anyway naturally on a billion year scale. It depends on what
one defines as 'positive', just as it depends on what one defines as 'up'.
Neither gravity nor entropy care, things will still 'fall' in the same way and
in the same direction.

The whole energy business is one of efficiency. How many % of the tapped source
turns into how many usable joules for how many $. And whether the particular
method used to tap Joules is liable to cause serious damage of some kind. It has
been calculated that the sun energy input to this planet is sufficient to supply
all energy needs a couple of times over. It is our inability to tap this source
directly or indirectly (and other sources) efficiently that causes problems.
(Or, said another way, humanity's preocupation with using energy is larger than
its preocupation with generating/finding sufficient energy for that growth -
like putting the carriage in front of the horses on a really big scale). When
and if tapped, the 'net' energy will still be negative. Similar considerations
apply to other resources, including chemical ones. Oil and fossil fuel are
'canned' solar energy after all. They are not 'renewable' because nobody can
wait 2 million years for new deposits to form naturally. From the point of view
of Earth, 2 million years is nothing. For humans, it's beyond forever. So it's
about the definition of 'renewable'. Or more exactly about the ratio between the
rate of consumption and the rate of production.

Peter P.


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