Oil 53

Receding Horizons for Alternative Energy Supplies

When energy optimists tout the huge supply of oil that is still available
to us in the form of tar sands and oil shale, they forget to mention that
costs are rising so quickly for producing that oil that these alternative
sources may prove to be of limited value. The same cost problems are
occurring in the renewable energy field as well. What is behind this
phenomenon sometimes referred to as the problem of receding horizons?

Those who claim that we will have plenty of energy and perhaps enough oil
for a hundred years or more have so far failed to understand why the rising
price of oil is making it more difficult both to extract new sources of oil
and to deploy renewable energy from wind and solar.

First, it is helpful to understand how complex energy systems actually
work. For this task we turn to the humble tree which gathers energy in ways
that are very much like those of human societies. The leaves on the top of
the tree quite obviously gather more sunshine than those below. So, why do
trees bother with all those leaves which only get partial sunlight? The
answer is that trees are not merely trying to obtain maximum energy gain
per leaf, but maximum energy gain for their whole structure. The best way
to do this is for the leaves at the top to support the leaves below with an
energy subsidy. The result is a total energy gain larger than that which
the leaves at the top could ever achieve on their own.

This pattern is seen throughout natural systems. Those systems try to
maximize their energy gain in order to increase their survivability and
reproduction. So, how do human societies maximize energy gain? They
diversify by providing an energy subsidy to incremental energy sources.
That subsidy comes primarily from our most widely available and versatile
energy source, oil.

Oil provides cheap liquid fuels used to explore for coal, natural gas and
uranium. In the cases of coal and uranium, liquid petroleum fuels are
essential to run the mining machinery which extracts them. These fuels are
also essential for the transport of coal and uranium ore to processing
facilities and finally to their places of use.
Lees verder: http://www.scitizen.com/stories/Future-Energies/2008/09/Receding-Horizons--for-Alternative-Energy-Supplies/