In article ,
Duane Bozarth wrote:
Robert Bonomi wrote:

In article ,
Duane Bozarth wrote:
Robert Bonomi wrote:
...

Have you ever run the numbers on how much biodiesel one can produce from
an acre of farmland in a year?

Ethanol is better deal to date, but biodiesel is coming on...net
positive energy ratios are improving every year w/ better hybrids and
improved processes...neither will ever be 100%, but are both net
positives.

Which relates to the question I posed, how?

How many acres of farmland does it take to produce say, 1,000 barrels of
either ethanol or biodiesel?

I'm not arguing about the efficiency of the conversion from 'raw' biomass to
'useable' fuel, Rather, I'm commenting on the ability, or lack thereof, to
supplant any significant amount of petroleum imports.

OK, I did find a reference...for ethanol, 2.65 gal(anhydrous)/bu corn.
At 200 bu/A (easy) that's 530 gal/A == ~17 bbl/A. So a 1000 bbl == 60
A.

Except those numbers don't add up.

200 bu/a is *really* optimistic. 140-160 is more the 'typical' range for
serious corn growing states -- e.g. Iowa, Nebr, Missouri, etc.
non-corn-belt states will be significantly lower yields. USDA figures
for the 2001 crop put the nation-wide yield at 131+ bu/acre -- the _third_
_highest_ number on record.

And a bbl of oil is 42 gallons.

Combined, you get a more realistic number of 9.46 bbl/acre.

Now, here's what I was leading up to ---

A car, driven 15,000 miles/year, and getting 25mpg, will need 14.285 bbl
of fuel/year. That's the output from 1.5 acres.

The entire corn crop for the state of Iowa, last year, was 1.2 million acres.
100% conversion to fuel, would be about 800,000 cars worth. Somewhat over
_half_ the cars registered in the state. Not counting any bus/truck/etc.
demand.

Automobile usage is a small part of total fuel consumption. like 1/5 or less.
of vehicular use. well under 10% of all petroleum consumption, when you
include oil-fired heating, farm implement, and marine use.

Iowa's _entire_ corn crop, used for fuel, might make a 2-3% reduction in
petroleum fuel usage in Iowa. With a realistic level of diversion to fuel,
you might get a 0.5% reduction _in_Iowa_. On a national basis, probably
an order of magnitude (at least) lower.