Environmental Engineering Reference
In-Depth Information
It is clear from the figures presented in Tables 1 and 2 that at a global level
there is more fossil fuel energy available than can be used in a world that is
serious about avoiding dangerous climate change. Numerous analyses have
demonstrated that a sizeable proportion of conventional fuel reserves must
remain in the ground if globally we are to avoid 2 1C or even 3 1C global
warming; a fortiori, unconventional fuels should remain unburnt.
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So why
are unconventional fuels being currently exploited and plans being put in
place to facilitate their exploitation, given global agreements to avoid dan-
gerous climate change? Putting aside the inertia of current global negoti-
ations on mitigation, in part, while Table 4 presents global availability of
fuels, these resources are not endowed uniformly. Regional availability of
different fossil fuels and demands differ, creating uneven market dynamics.
There are regions of the world where access to conventional gas is more
limited, leading to reliance on coal; thus here, shale gas could, with the
caveats stated below, play a role. Shale gas has been described, therefore, as
a transition fuel, enabling countries and regions currently highly reliant on
the more carbon-intensive coal generation to reduce the carbon intensity of
their energy system as part of a low-carbon transition. The role of shale gas
in a low-carbon transition is, therefore, dependent on where it is used and
what it displaces - this is determined at present, to a great extent, by energy
markets.
4
Shale Gas as a Transition Fuel
4.1 Conditions and Evidence to Date
The position of shale gas as a transition fuel relies on the assumptions that:
(1) it completely displaces the use of an alternative more-carbon-intensive
fuel choice; (2) growth in energy demand does not outpace carbon-intensity
savings; and (3) it acts as a bridge between current high-carbon-intensive
energy systems based on coal and lower future systems where renewables,
carbon capture and storage (CCS) and nuclear energy play a dominant role.
First we consider part (1) and the evidence to date that this condition is
met by shale gas exploitation. Much of the potential benefit conveyed by
shale gas derives from its potential to reduce the carbon intensity of elec-
tricity production. The net effect of displacing coal with shale gas depends
very much on the region of the world under consideration and the energy
prices therein. In the case of the USA, with no national drivers to reduce coal
use, evidence suggests that during the rapid exploitation of shale gas and
corresponding price reduction, locally, within the USA, there was some
displacement of coal use in electricity generation. In fact, between 2005 and
2012 carbon emissions from energy use in the USA fell by 12%, in part due to
a reduction in coal consumption of 25% during the same time frame.
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However, during the same time frame much of the displaced coal pro-
duction was sold on global markets, exported and burnt elsewhere. The 32%
drop in EU coal import prices between 2005 and 2011 and an increase of US
