Ethanol shows great promise as a valuable contributor to the world's
energy needs. But, given current technology, there is not enough land
to make ethanol feasible as a sole fuel supply for automobiles. The
most optimistic estimate I've seen is that there may be sufficient
usable land worldwide to produce 100 billion gallons of ethanol a
year. This would not replace the current gasoline consumption of the
United States, much less the world. If all the arable land on Earth
were to be devoted to the growth of crops for the production of
ethanol, there would be no room for the growth of food crops, and
mankind would starve. If all the Earth's rainforests were destroyed in
order to create more arable land, ecological disaster would be a
"Almost all of the arable land on Earth would need to be covered with
the fastest-growing known energy crops, such as switchgrass, to
produce the amount of energy currently consumed from fossil fuels
U.S. Department of Energy: Basic Research Needs
"The Institute for Local Self-Reliance has calculated that there is
sufficient land (that is not currently growing food) and waste
materials available to produce over 100 billion gallons of ethanol a
year, on a sustainable basis."
New Rules Project: Ask Dr. Dave
"The technology and the economics aren't there yet to produce enough
ethanol for a massive switch to E85, says Bob Dinneen, president of
the Renewable Fuels Association (RFA), a trade group that represents
Reaching the potential is limited by the production available. After
doubling in size, then doubling again the past few years, the ethanol
industry consists of 95 U.S. plants that produced 4 billion gallons
last year. That's only enough to replace 3% of the 140 billion gallons
of gasoline the USA burned last year. And it's almost ridiculously far
from the 119 billion gallons of ethanol necessary for a nationwide
switch to E85.
An additional 32 ethanol plants are under construction, and nine are
being expanded. That will add about 1.8 billion more gallons annually
but still leaves ethanol a bit player in the fuel game."
USA Today: Is ethanol the answer?
"[Michel-Marc] Delcommune and his team tried to assess the impact of
hybrid cars on the bio-fuels market, such as corn-based ethanol.
'By pushing the analysis on hybrid cars, what we discovered were the
limits of this phenomenon, because there is not enough land to grow
the raw material of ethanol,' Delcommune says."
CFO Europe: Covering all bets
"The team was looking not to the next two or five years-as their
competition did-but at the next 10 or 20 years, the next century. And
to them, the answer was clear: hydrogen. 'I don?t think in the long
run there?s an option for anything else,' says [Matt] Stevens.
'Ethanol and biodiesel are good short-term solutions. But they can?t
be the ultimate solution. There?s just not enough land to grow the
corn and soybeans'."
University of Waterloo: Challenge X
"However, there are many reasons why even environmentalists object to
biofuels as a large-scale solution for climate change and development.
Firstly, there is not enough land to provide for the world's current
level of oil need if it is to be met by biofuels. Developed countries
are likely to encourage developing countries to use their land for
biofuels for export. Oil prices are likely to rise in the next years,
as are biofuels. Governments and agribusinesses will find that they
can make more money by using land to grow fuel for western cars, than
they can to grow food for their citizens."
Organic Consumers: Biofuels
"According to the Cornell study, to create one gallon of ethanol, it
takes 21.6 pounds of corn, and one acre of land can yield a total of
7,100 pounds of corn. Corn is also grown on a yearly basis, so that
equals out to about 328 gallons of corn for every acre grown per year.
According to the Department of Energy, the United States currently
demands around 9.2 million barrels of oil per day (just for gasoline),
and a barrel holds about 42 gallons each, which means that the U.S.
demands close to 378 million gallons of gasoline per day. If all cars
ran on ethanol, which is not as efficient as gasoline, the U.S. would
need around 567 million gallons of ethanol per day. Doing the math,
the U.S. would have to grow close to 1.7 million acres of corn per
day, or over 630 million acres of corn per year, just to produce
enough ethanol to feed the yearly U.S consumption rate. For further
comparison, one acre of land is equal to 4.04 kmē, so the U.S. would
need to grow around 2.5 billion kmē of corn per year to fuel its
thirst. To put this in perspective, the Earth's surface area
(including oceans) is only 510 million kmē, so it would take the land
surface of five Earths to feed the U.S. demand for ethanol for one
Radford University: E85 Ethanol Grows in Popularity, but it's not the Answer
My Google search strategy:
Google Web Search: ethanol OR biofuel "enough land"
I hope this is helpful. If anything is unclear or incomplete, please
request clarification; I'll gladly offer further assistance before you
rate my answer.
Clarification of Answer by
11 May 2006 12:00 PDT
Hydrogen, like ethanol, is likely to serve as a meaningful piece of
the puzzle, but I don't think any reputable source would say that
hydrogen is currently viable as a sole replacement for gasoline.
"Setting up a hydrogen economy would require huge investments in the
infrastructure to store and distrubute hydrogen to vehicles, in
addition to the R+D cost of the vehicles themselves. In contrast,
electric battery vehicles which are currently at a similar stage of
technological maturity, don't require infrastructure investments.
Since hydrogen is likely to be produced with the same sources as
electricity (fossil, nuclear, solar, wind) it may less economical than
a pure electricity economy.
There is concern about the energy-consuming process of manufacturing
the hydrogen. Manufacturing hydrogen requires a hydrogen carrier such
as a fossil fuel or water. The former consumes the fossil resource and
produces carbon dioxide, while electrolyzing water requires
electricity, which is mostly generated at present using conventional
fuels (fossil fuel with lower but still some CO2 emission or nuclear
power). While alternative energy sources like wind and solar power
could also be used, they are still more expensive given current prices
of fossil fuels and nuclear energy. In this regard, hydrogen fuel
technology itself cannot be called truly independent of fossil fuel
dependence, unless a totally nuclear or renewable energy option were
Wikipedia: Hydrogen economy