ETHANOL, supposedly an ultra-clean miracle fuel, is actually an energy-waster
that creates more pollution than the petrol it replaces, claims a former US
government adviser. If he is right, it could mean the burgeoning billion-dollar
ethanol industry is nothing more than an economic white elephant.
Agricultural scientist David Pimentel came to this conclusion in the early
1980s when he chaired a Department of Energy study into the economic and
environmental impact of ethanol. Over the past 20 years, scientists working for
the US Department of Agriculture (USDA) say that improvements in farming
practices and ethanol processing have boosted the fuel鈥檚 efficiency. But
Pimentel, now at Cornell University in New York, says it still takes far more
energy to convert corn to ethanol than the fuel produces when burnt.
Government scientists say Pimentel鈥檚 arguments are outdated and flimsy. 鈥淗is
analysis was true 20 years ago but it is not true today,鈥� says Hosein Shapouri,
an agricultural economist with the USDA.
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When added to petrol, ethanol boosts its oxygen content, leading to cleaner
combustion and reducing the formation of greenhouse gases and smog. Fuels
containing about 10 per cent ethanol are used across the mid-Western states and
in pockets elsewhere. Pimentel鈥檚 study has ignited the debate over whether
ethanol is succeeding on its merits or because of heavy government subsidies and
lobbying from America鈥檚 grain growers.
Pimentel calculates that it takes the equivalent of 10,000 litres of oil and
petrol to grow each hectare of corn. Fermenting grain and distilling the ethanol
uses further energy. In total, 36,500 kilojoules are needed to make one litre of
ethanol, yet it produces only 21,400 kJ when burnt. Pimentel will publish his
study next month in the Encyclopaedia of Physical Sciences and
Technology.
His conclusions conflict with a recent government study, which found that
ethanol produces a surplus of 5600 kJ per litre. 鈥淲e gathered input from teams
of university scientists, farmers and ethanol processors,鈥� says Michael Wang at
Argonne National Laboratory in Illinois. Wang says Pimentel failed to account
for technological advances.
Pimentel admits to using old data, but says it doesn鈥檛 change his findings.
Public money is being used to prop up an inefficient energy source, he says,
adding that making ethanol produces more pollution than comes from burning an
equivalent amount of petrol. Land used to grow corn for ethanol would be better
used to supply food and cattle feed, he suggests.
Shapouri accepts that the government pays ethanol producers a hefty subsidy
of 14 cents per litre鈥攔oughly a third of its market price鈥攂ut he
points out that the oil and gas industries are also heavily subsidised.
Despite Pimentel鈥檚 warnings, corn growers and ethanol manufacturers see a
golden future ahead. The National Corn Growers Association recently persuaded
Congress to force California to use ethanol instead of MTBE, a polluting petrol
additive. The move will increase ethanol demand in the US to nearly 12 billion
litres a year by 2004, nearly double this year鈥檚 output.