Brown's article overlooks the fact, that not all farming systems
are as energy dependant as those in North America. Australia's clover-ley farming rotations for instance, replace much oil based nitrogen with legume based nitrogen. Wheat for instance does not need irrigation either.

Roger Crook, one of our scholars here in the West, claims that a tonne of wheat can create 400l of ethanol. I haven't checked his figures, but if he is correct, then clearly Brown is wrong, or his farming model to create ethanol is wrong.

Where do they come from. In Australia today a wheat farmer, farming less than 1000 acres, single handed, is heading for bankruptcy. This takes lots of energy, as in the USA, or any where else. 30 years ago, one good crop in three was viable. Now its two in three, & many of our wheat farmers are going out backwards. Then we get clover-ley farming. In fact it takes more oil to plant clover than it takes to make the fertaliser the clover can produce. Ethanol will never be a viable replacement for petrol, the imputes are just too great for it to work. Bio diesel has some prospect, but where do we find an extra 20 million acres of productive farm land. Hydrogen has to be the answer, but unless it is produced by electrolyses it uses more oil than it saves, & the electrolyses will have to be with solar or nuclear generated power. As another fossil nuclear has a limited life so its solar, & it will probably take less than 20 million acres to produce. All the airy fairy rubish about wind, co generation etc has to stop, It just takes our eye off the main game. Brisbanes co generation plant is a huge flop, as expected. Trying to run a plant on 2 or 3 different fuels is just not viable. Then we get the myth of public transport. All our cities grew up with the car. We are not europe. It can not work while we live & work where we currently chose, & transport will have to be prohibitively expensive before we will change. Besides, any number of studies tell us that public transport uses 15% more energy, per passenger mile, than private cars. If we could just get the greens, the academics & the planners off the pipe dreams of what they would like to have work, & on to what has a chance of working we will be a lot cloesr to a moving in the right direction.
Hasbeen

"In fact it takes more oil to plant clover than it takes to make the fertaliser the clover can produce. Ethanol will never be a viable replacement for petrol, the imputes are just too great for it to work. Bio diesel has some prospect, but where do we find an extra 20 million acres of productive farm land"

Hasbeen, you clearly havent the foggiest about farming :) Clover takes just a few litres of biodiesel to sow, can add nitrogen to the soil for years and years in quite large amounts. Hardseed ensures that it won't need resowing during the crop cycle. Yes, 1000 acre wheat farms are too small, today they are 5000 acres. A small % of their land is all it takes to grow enough biodiesel to grow all the wheat you want, or other energy crops. As nobody wants wool anymore, no reason the sheep flock can't be halved to make space for energy crops, thats alot of land.

The energy solution will come from many sources, all playing a role. Ethanol, biodiesel, gas, (convert your car tomorrow if you wish), efficiency, solar, wind. After all its not as if any oil tap is being shut off tomorrow, that stuff will be around too for the next 100 years or so.

The points made about Brazilian ethanol being a clearcut net energy producer are documented in
http://www.bbibiofuels.com/worldsummit/files/Carvalho-WSET.pdf
with Energy returns now being about 8 to 11 FOLD (eg 800% plus). Potential energy return from any cellulose biomass in the feedstock will be much higher than presently achieved too, as the new economic cellulose hydrolysis method developed by NREL-Genencor-Novozymes comes on stream. Currently this is being trialled in Spain at Abengoa's ethanol plant, to be commissioned 2006. This Spanish plant will convert wheat straw to ethanol in first instance.
Current conversion of starch feedstocks to liquid fuel should be regarded as a loss leader option to enable rapid introduction of cellulose (straw) plus starch conversion processes using Novozyme or similar enzyme catalysts by about the year 2010. These offer approx. double the energy return of current starch based feedstocks.
Bear in mind that energy efficiency in the Brazilial biofuel industry underwent a steady improvement over the past 30 years learning curve, and cereal based biofuel will do this also in the future. For example synthetic N fertilizer input fossil fuel energy can be reduced by innovation in genetics and chemistry.
gmopundit.blogspot.com

Spin doctor Jeremy Brown can not escape the fact that at some point in the future there will not be any oil.

The problem with analysis like Brown's and most of the rebuttal is that it is very difficult to account for inputs accurately and universally. The solution is to have a market in carbon emissions, then the price mechanism will determine what technological answer is the most appropriate in which circumstances and there will be no need to account at all.