[permaculture] [Fwd: [SANET-MG] The False Hope of Biofuels]
Lawrence F. London, Jr.
lfl at intrex.net
Thu Jul 20 10:56:45 EDT 2006
The Washington Post
The False Hope of Biofuels
For Energy and Environmental Reasons, Ethanol Will Never Replace
By James Jordan and James Powell
Sunday, July 2, 2006
Biofuels such as ethanol made from corn, sugar cane, switchgrass and
other crops are being touted as a "green" solution for a large part of
America's transportation problem. Auto manufacturers, Midwest corn
farmers and politicians are excited about ethanol. Initially, we, too,
were excited about biofuels: no net carbon dioxide emissions, reduction
of oil imports. Who wouldn't be enthusiastic?
But as we've looked at biofuels more closely, we've concluded that
they're not a practical long-term solution to our need for transport
fuels. Even if all of the 300 million acres (500,000 square miles) of
currently harvested U.S. cropland produced ethanol, it wouldn't supply
all of the gasoline and diesel fuel we now burn for transport, and it
would supply only about half of the needs for the year 2025. And the
effects on land and agriculture would be devastating.
It's difficult to understand how advocates of biofuels can believe they
are a real solution to kicking our oil addiction. Agriculture Department
studies of ethanol production from corn -- the present U.S. process for
ethanol fuel -- find that an acre of corn yields about 139 bushels. At
an average of about 2.5 gallons per bushel, the acre then will yield
about 350 gallons of ethanol. But the fuel value of ethanol is only
about two-thirds that of gasoline -- 1.5 gallons of ethanol in the tank
equals 1 gallon of gasoline in terms of energy output.
Moreover, it takes a lot of input energy to produce ethanol: for
fertilizer, harvesting, transport, corn processing, etc. After
subtracting this input, the net positive energy available is less than
half of the figure cited above. Some researchers even claim that the net
energy of ethanol is actually negative when all inputs are included --
it takes more energy to make ethanol than one gets out of it.
But allowing a net positive energy output of 30,000 British thermal
units (Btu) per gallon, it would still take four gallons of ethanol from
corn to equal one gallon of gasoline. The United States has 73 million
acres of corn cropland. At 350 gallons per acre, the entire U.S. corn
crop would make 25.5 billion gallons, equivalent to about 6.3 billion
gallons of gasoline. The United States consumes 170 billion gallons of
gasoline and diesel fuel annually. Thus the entire U.S. corn crop would
supply only 3.7 percent of our auto and truck transport demands. Using
the entire 300 million acres of U.S. cropland for corn-based ethanol
production would meet about 15 percent of the demand.
It is argued that rather than using corn to make ethanol, we can use
agricultural wastes. But the amounts are still a drop in the bucket.
Using the crop residues (called corn stover) from corn production could
provide about 10 billion gallons per year of ethanol, according to a
recent study by the U.S. Energy Information Administration. The net
energy available would be greater than with ethanol from corn -- about
60,000 Btu per gallon, equivalent to a half-gallon of gasoline. Still,
all of the U.S. corn wastes would produce only the equivalent of 5
billion gallons of gasoline. Another factor to be considered: Not
plowing wastes back into the land hurts soil fertility.
Similar limitations and problems apply to growing any crop for biofuels,
whether switchgrass, hybrid willow, hybrid poplar or whatever.
Optimistically, assuming that switchgrass or some other crop could
produce 1,000 gallons of ethanol per acre, over twice as much as we can
get from corn plus stover, and that its net energy was 60,000 Btu per
gallon, ethanol from 300 million acres of switchgrass still could not
supply our present gasoline and diesel consumption, which is projected
to double by 2025. The ethanol would meet less than half of our needs by
Perhaps more important: The agricultural effects of such a large-scale
program would be devastating.
Recently, there has been lots of excitement and media coverage about how
Brazil produces ethanol for its automobile fuel and talk that America
should follow its lead. But Brazil consumes only 10 billion gallons of
gasoline and diesel fuel annually, compared with America's 170 billion.
There are almost 4 million miles of paved roads in America -- Brazil has
60,000. And Brazil is the leading producer of sugar cane -- more than
300 million tons annually -- so it has lots of agricultural waste to
Finally, considering projected population growth in the United States
and the world, the humanitarian policy would be to maintain cropland for
growing food -- not fuel. Every day more than 16,000 children die from
hunger-related causes -- one child every five seconds. The situation
will only get worse. It would be morally wrong to divert cropland needed
for human food supply to powering automobiles. It would also deplete
soil fertility and the long-term capability to maintain food production.
We would destroy the farmland that our grandchildren and their
grandchildren will need to live.
/The writers are research professors in Maglev Research Center at
Polytechnic University of New York. /
The False Hope of Biofuels
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