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The Environmental and Economic Viability of Ethanol-Based Fuels
Harwant Sethi
1-26-17
Introduction:
It’s no secret that the United States and the rest of the developed world rely too heavily
on oil to power their economies. In an effort to wean our nation’s vehicles off of gasoline, the
United States government has subsidized the production of ethanol from corn so that it may be
used as a component of automobile fuel. This process, while potentially beneficial to the farmers
who grow the $4.5 billion annual corn crop, is extremely resource intensive and highly
inefficient from a scientific perspective. In this paper, I will investigate the pros and cons of the
United States ethanol fuel market, and evaluate its success against a far more robust ethanol
production system in Brazil.
E85: Ethanol as an Alternative Fuel:
Since the late 1990s, both the United States government and American automakers have
been pushing ethanol-based fuels as a “green” alternative to gasoline. The most common
derivative of ethanol fuel in the United States is marketed as “E85”, a mixture of 85% ethanol
and 15% gasoline. This mixture was largely chosen in an effort to allow automakers to keep
their existing internal combustion engine designs and still manage to power their vehicles with
ethanol. Only minimal engine tuning changes are required to allow a vehicle to harness the
power of ethanol as a fuel. These changes include coating any magnesium or aluminum
components of the fuel delivery system in order to protect them from the corrosive ethanol in
E85, and the addition of pulse-controlling fuel injectors that can sense ethanol, and allow more
liquid into the fuel-air mixture in order to maintain power levels similar to that of gasoline
(Brusstar, 2002). Unfortunately, since these flex-fuel motors maintain the combustion ratio of
internal combustion engines already powering American vehicles, they are optimized for
gasoline, and not E85. This is due to the lower energy density of ethanol compared to
petroleum-based gasoline. In order to maintain similar power from the same amount of fuel, the
compression ratio of these existing engines would need to be significantly higher, requiring a
major research and development effort and potentially even all-new engine designs. Maintaining
power output in a gasoline engine that runs on E85 means that more fuel must be used to obtain
the same horsepower and torque, causing fuel economy to suffer by 15-24%, according to a U.S.
Department of Energy study (U.S. DoE, 2014).
So why ethanol? It doesn’t seem to offer a whole lot of improvement over gasoline, as it
adds to the complexity of engine design, and kills fuel economy. Well, for one, ethanol was seen
as a step towards energy independence, as ethanol from U.S-grown corn makes up 85% of E85
by volume, cutting demand for imported oil. Secondly, the United States government knows that
its farmers grow a significant amount of corn, and that the nation is capable of producing enough
of the crop to make ethanol. The United States government drove demand for this corn by
allowing fuel “blenders” to receive a 45-cent per gallon tax rebate on ethanol-blended fuels.
This virtually forced fuel blenders to demand more corn, which raises the market equilibrium
price of corn. This tax credit was allowed to expire in 2011, but a minimum 10% ethanol content
in still legally mandated in all gasoline. While this demand increase is puts some money in
farmers’ pockets, it comes at the expense of the American taxpayer, who faced steeper prices at
the grocery store. This price increase is not limited to corn, as a significant portion of America’s
processed foods use corn starch, high fructose corn syrup, and other corn-based ingredients.
When corn prices go up, production costs go up too, and the American taxpayer is left holding
the bill (Murse, 2016).
The Questionable Environmental Benefits of E85:
A common misunderstanding regarding E85 is that its’ decreased emissions are due to
the fact that ethanol doesn’t form greenhouse gases when burned. Like any other combustion
reaction, ethanol, when combusted in the presence of oxygen, forms water and carbon dioxide
according to the following reaction:
𝐶2𝐻6𝑂 + 3𝑂2→ 2𝐶𝑂2+ 3𝐻2𝑂
Similarly, gasoline undergoes a combustion reaction in the presence of oxygen, to the tune of:
2𝐶8𝐻18 + 25𝑂2→ 16𝐶𝑂2 + 18𝐻2𝑂
Now, obviously, the combustion of ethanol produces less CO2 per unit volume, but it is nevertheless not a
carbonless process. Furthermore, this decrease in carbon emissions is countered somewhat by the fact
that E85 as still 15% gasoline by volume, and the fact that in flex-fuel engines it burns far less efficiently
than gasoline. While E85 produces far fewer carbon emission per unit volume, its advantage over
gasoline on a per-mile-travelled basis is decidedly less impressive. This, however, is merely the tip of the
iceberg when it comes to the mess that is E85 and corn-based ethanol in the United States.
A study out of Cornell University in 2000 set out to determine the environmental impact of U.S.
ethanol-fuel production, from seed to tailpipe. In this study, titled “Ethanol production using corn,
switchgrass, and wood; biodiesel production using soybean and sunflower”, authors David
Pimentel and Tad W. Patzek find that ethanol production provides a net loss of energy, and is
therefore a waste. From the start, Pimentel and Patzek find that simply harvesting corn requires
a considerable amount of energy (271 gallons of gasoline per hectare, about $917 worth of fuel).
Given that a hectare is capable of producing around 8650 kilograms of corn, which sells for
about 11 cents per kilogram, this means that farmers spend 96% of the market value of the corn
on fuel for harvesting. Still, given the massive size of some corn farms and the government
subsidies available to corn farmers, the $35 in profit per hectare is still deemed economically
efficient. This, however, is merely the first step on the road from corn to fuel. After accounting
for corn transport, water requirements, electricity, and the three-step distillation of corn to
ethanol, the authors estimate that the total input of energy to produce a liter of ethanol is
somewhere in the neighborhood of 6,600 kilocalories of energy. This one liter of ethanol
produces a measly 5,100 kilocalories of energy when burned, resulting in a net energy loss
through the production process. Not only are the economic implications of such an inefficient
process dire (without the heavy government intervention in the market through the $3-8 billion
annual ethanol subsidy, this simply wouldn’t be economically viable) but the environmental cost
is also enormous. 60% more ethanol is required to produce the energy that gasoline produces,
