Рубрика:
62
Text 10
ADDING FUEL TO THE FIRE
When the concept of biofuels first emerged, it sparked huge optimism as a source of
renewable energy. This dream is far from being realized, as questions have arisen
about the viability of biofuels both ethically and energetically. Despite this, the desire
to overcome rising fuel costs, global warming, and dependence on politically unstable
oil exporting regions has prompted ambitious moves towards increasing biofuel
consumption – the EU aims to increase biofuel use in road traffic by over 1000% by
2020. Research into biofuels is ongoing, and looks set to yield positive, usable
technologies, but will our premature enthusiasm for using biofuels actually do more
harm than good?
At present the term ‘biofuels’ is usually applied to liquid transport fuels: biodiesel
from vegetable oils or bioethanol fermented from sugar, starch or biomass. Most car
engines can take a 15% cut in standard diesel or petrol with no modification and
could be modified to run entirely on biofuel. The idea behind biofuels is simple: any
carbon released when they burn should be balanced by the carbon absorbed during
the growth of the plants that are their raw material, making them carbon neutral.
Since there is no net change in atmospheric carbon, there should be no perturbation to
our climate – so far, so good.
However, the truth is that most biofuels currently in use are not carbon neutral at all.
The problem is that cultivating the plants, harvesting, transport and processing all use
energy. Many liquid biofuels are based on non-structural oils and sugars, which are
present in relatively low concentrations in plants, and require considerable
processing. Estimates of efficiency vary widely, and are different for different types
of fuel. A recent report by the UK government estimated that a 50-60% net reduction
in emissions is achieved using biofuels compared with fossil fuels, but critics have
claimed that some types of biofuel may even take more energy to produce than they
supply.
This is far from being the only problem. Turning food crops into fuel creates financial
competition between rich consumers wanting fuel and poor consumers wanting food,
for both the crops themselves and the land used to grow them. This could contribute
to famine in the developing world, upon whom we would be heavily dependent for
biofuel production and food prices in the developed world may rise. Some proponents
of biofuels claim that enough energy could be produced using present technology
without compromising food security. With projected world energy requirements in
2052 likely to require 80% of the world’s surface to be planted, and food demands
set to double over the same period, this confidence seems utterly unfounded.
Increased crop production for biofuels will also lead to wide-scale habitat loss. This
decreases biodiversity and increases emissions directly from the clearance of the
natural vegetation and disruption to the soils, generating a ‘carbon debt’ – the number
of years the fuel must be produced to ‘pay back’ the initial emissions from land
clearance, determined by a combination of the type of fuel produced and the type of
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