BIO-FUELS
Are biofuels really the greenhouse-busting answer to our
energy problems?
It’s not that simple, says Fred Pierce
A.
Soon, we’re told, corn crops will be as valuable
as oil. This is because corn and a few other crops are being promoted as the ‘biofuels’
of the future. Biofuel is an umbrella term used to describe all fuels derived
from organic matters. The two most common biofuels are bioethanol, which is a
substitute for gasoline, and biodiesel. Not only have soaring oil prices made
biofuels economically viable for the first time in years, but they could also
help countries reduce their dependency on fossil fuel imports. However, the
real plus point in the minds of many is their eco-friendly image.
B.
Supporters claim they will cut our net
greenhouse gas inputs dramatically, because the crops soak up carbon dioxide
from the atmosphere as they grow. Given this fact, it’s no surprise that
politicians and environmentalists the world over are backing the idea, hoping
we will soon be using this green alternative to power our cars, buses and
trains. Other scientists, however, have begun to question the environmental and
social arguments for biofuels. Far from solving our problems they believe
biofuels will destroy rainforests, suck water reserves dry, kill off species
and raise food prices. Worst of all, they exclaim that many biofuels will
barely slow global warming at all if the technology behind them does not
improve. Biofuel supporters counter that it’s still early days, and we should
give this technology the time and investment to deliver on its promise. So who’s
right?
C.
The controversy may be brand new, but the
biofuels themselves are an old idea. The Model T Ford, first produced in 1908,
was designed to run on ethanol, and Rudolf Diesel, who invented the diesel
engine in 1892, ran his demonstration model on peanut oil. Biofuels fell out of
favour as petroleum-based fuels appeared and became cheaper to produce, but,
after the oil crisis of the early 1970s, some countries returned to biofuels. For
example, Brazil has been producing large, quantities of ethanol from sugar cane
for over 30 years. Brazilian law now requires that 20 per cent of fuel be
blended with bioethanol, which all gasoline-powered cars can tolerate. Over 15
per cent of Brazil’s cars can even run on pure bioethanol.
D.
According to a recent study by the Worldwatch
Institute, for Brazil to produce ten per cent of its entire fuel consumption requires
just three per cent of its agricultural land. So it’s not surprising that other
places want to emulate Brazil’s approach. The problem is that in most other
countries, the numbers don’t add up. The same study estimated that to meet that
ten per cent target, he US would require 30 per cent of its agricultural land,
and Europe a staggering 72 per cent. It’s no secret way things stack up so
differently. Not only do Brazilians drive far less than Europeans and Americans,
their fertile land and favourable climate mean their crop yields are higher,
and their population density is lower.
E.
Several research groups have tried to compare
fossil fuel emissions with those of corn bioethanol at every stage of
production from seed sowing to fuel production. The studies have been beset by
scientific uncertainties, such as how much of the greenhouse gas nitrous oxide
is produces by the nitrogen fertiliser used in growing corn. Opinions are
divided as to what should and should not be included in the calculations, which
means the results vary widely, but a study by David Pimentel at Cornell University
in New York concluded that corn ethanol creates more greenhouse gases than
burning fossil fuel.
F.
Another reason a growing number of people oppose
biofuels is that the growing corn for ethanol uses up land that is currently supplying
food to the world. According to Lester Brown, veteran commentator and activist
on food politics, the corn required to fill a 4x4 tank with bioethanol just
once could feed one person for a year. He predicts that a boom in bioethanol
would lead to a competition between the 800 million people in the world who
live on less than $2 a day, many of whom are already spending over half their
income on food.
G.
So are we utterly mistaken to think that
bioethanol could usher in an era of greener energy? The way things are developing,
it certainly looks that way, but it needn’t be so. Scientists want to protect a
way to make biofuels from non-food crops and waste biomass, saving the corn and
other food crops for food use, and to do it without wrecking natural
ecosystems. Already researchers are discovering ways to convert cellulose-rich
organic matter into ethanol. Cellulose is the main structural component of all
green plants. Its molecules comprise chains of sugars strong enough to make
plant cell walls. If you could break down those molecules to release the sugars
they contain, you could ferment them until ethanol is created. Developing such
a process could open the door to many non-food materials such as switchgrass –
a wild grass that thrives in the eastern states and Midwest of the US – straw,
crop residues like stalks and hardwood chips. Its supporters say these
cellulose materials could deliver twice as much as ethano per hectare as corn,
and do it using land that is today neither economically productive nor
environmentally precious. Some even think municipal wate such as paper,
cardboard and waste food could also be used.
If the numbers add up this could be the development that
may yet deliver us from our dependence on oil, without costing us the Earth in
the process
Reading Passage above has seven
paragraphs A-G
Which paragraph contains the
following information?
Write the correct letter A-G next to the statements.
1.
_____reasons for the success of bioethanol
production in one region.
2.
_____an individual’s prediction of the
consequences of increasing production of corn ethanol.
3.
_____a reference to why biofuels might help to
slow down global warming
4.
_____a definition of biofuel
5.
_____a reference to research that found one type
of bioethanol to be less eco-friendly than oil
6.
_____examples of how ethanol was used as a fuel
petroleum
Questions 7-11
Complete the summary below
Choose NO MORE THAN TWO WORDS
from the passage for each answer.
Using Non-Food Crops to Make Biofuels
A major constituent of green
plants is cellulose. The _________ (7)of cellulose are made up of sugars. These
form of the _____ (8)of plants. Ethanol could be produces by extracting the
sugars and allowing them to _____(9). One common North America plant that could
be used in this method is _____(10). Some scientists believe that this would be
a more productive source of ethanol than _____(11). Additionally, the source
plant materials could be grown in ground which is not currently being used for
agriculture and is not _______ (12) valuable.
13.
What conclusions does the writer of the text
come to?
A. Bioethanol made from sugar cane will be the
cheapest fuel worldwide.
B. The US could become self-sufficient in biofuel made
from corn
C. A biofuel may be made in time which does not damage
the environment
D. Scientists agree that some form of bioethanol is the
future of fuel
ANSWER KEY
1.
D
2.
F
3.
B
4.
A
5.
E
6.
C
7.
molecules
8.
cell walls/ structural components
9.
ferment
10.
switchgrass
11.
corn
12.
environmentally
13.
C
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