Geoscience Reference
In-Depth Information
irrespective of whether or not they fully meet energy demand. They can tell us whether
the resource is likely to be a major economic one for years, decades or longer, after
which it will become more scarce/expensive, or be less economically competitive,
and perhaps indicate a time when other (possibly more expensive) energy resources
may become more competitive. In greenhouse terms r / p ratios are suggestive of the
minimum time in which under B-a-U fossil resources are likely to make major con-
tributions to atmospheric carbon dioxide. Of course, 'business' is unlikely to remain
'as usual' the further into the future one projects a forecast and so no meaningful
estimate can be made as to fossil fuel consumption in the 22nd century or beyond.
Among the various wild cards are the roles the various alternative resources will play.
Alternative (non-fossil) energy resources are in the main currently more expensive
than fossil fuels and/or have other problems associated with them. Renewable energy
from so-called flow resources such as tidal, wind and wave power ('flow' because
unlike 'fund' resources, there is a continual energy flow to be harvested) has a lower
energy density and so requires a larger area for its exploitation, hence a large land-use
impact. Conversely, finite fund resources such as fossil fuels and uranium have high
energy intensities. Biofuels, although carbon-based, do not short-circuit the deep
carbon cycle, and do take up productive land that could be used for food crops. This
needs to be taken into account. We need to remember, against a backdrop of a growing
global population, that land for which there will be an increasing food-crop demand
has competing use options. Biofuels have a significant biological opportunity cost,
being the cost of a venture in terms of lost opportunity of another venture. In short,
agricultural land can be used for food or energy crops, or even a mix, but one will
always tend to offset the yield from another. There are also non-biological opportunity
costs, for the agricultural land might be sold and used in a non-biological way such
as to provide a site for a factory.
Other than sources of renewable energy, the other principal energy alternative to
fossil fuels is nuclear power. The cost of nuclear generation is generally considered
at best comparable with the cleanest and most efficient of coal stations but is usually
more expensive. Its advantages are that it furthers a nation's energy security and, of
course, has a small greenhouse impact. Its disadvantages (other than cost) are that
it has other environmental impacts, chief among which is the problem of long-term
disposal of radioactive waste. This is a financial unknown and has not generally been
completely solved to public and political satisfaction. Further, much of the unknown
component of the cash cost of long-term disposal will not be incurred until many
years into the future so that, unless a provision is made today to put aside some of the
income from the sale of nuclear-generated electricity, there will be an intergenera-
tional transfer of externality ('externality' because this cost is external to the price of
the electricity sold). In this sense nuclear power is similar to power arising from fossil
fuels in that the consequential global warming generates an environmental impact
with economic consequences for future generations to bear. Economists therefore say
that both fossil fuel use and nuclear power currently have environmental externalities
associated with them, which in turn have intergenerational transfer consequences.
(The issue of nuclear waste will be touched upon briefly in the next chapter.)
Then there is the question of how much fossil carbon is used by nuclear power.
It has been said that nuclear power is not a zero-carbon energy source as fossil fuel
energy is required to mine, transport, process and refine (enrich) uranium ore. This is
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