Another look at crop biofuels

[GliderGuider]

This doodling was prompted by a post on The Oil Drum.

That poster observed that every year we grow only 2 gigatonnes of grain but use 4 gigatonnes of oil. Given that grain carry-forward reserves are declining (to only 53 days' supply this year) and that we've eaten more grain than we've grown in 7 of the last 8 years, it's instantly obvious that every liter of crop-sourced biofuel that goes into a fuel tank comes directly out of someone's stomach. Ultimately it comes out of a poor brown someone's stomach.



Once I stopped retching, I wondered how much net biofuel that 2GT of grain would actually produce. Well, I know from previous research that the ethanol yield from grain averages around 400 liters per tonne. Correcting for the density of ethanol (0.789 kg/liter) we get about 0.32 tonnes of ethanol per tonne of grain. So we can produce a total of 631 million tonnes of ethanol.

Now, assuming all the process energy for the ethanol production comes from that same fuel stream (i.e. we use up some of the ethanol to make the portion we end up using), and assuming that the EROEI of crop ethanol is 1.3:1, the net ethanol production is (631,000,000*(1.3/2.3)) = 357 million tonnes of ethanol. In order to compare this to oil you need to factor in the lower energy content of ethanol, which is about 2/3 that of oil. So our net ethanol gives us 357*.66 = 235 million tonnes of oil equivalent.

Every year we use 4 billion tonnes of oil. If we turned all the world's grain into ethanol we would end up with 9% of that.

Do we really think that just because the corn shipped to an American ethanol plant was grown in Iowa, that it didn't come indirectly out of the diet of someone in a poor developing country?

[dipsydoodle]

1. I did read

that complete conversion to biofuel would require almost the entire conversion of the land mass of the USA over to appropriate crop production. The article did not mention WTF the population would eat.

[madrchsod]

3. let`s see....crop production depends on..

late or early spring,snow cover or lack of snow cover,not enough rain or to much rain,early frost late frost,corn moisture to high ,and of course the price of seed the next year.i`m not including the cost of employees,machinery,and transportation.then you have to go to the market and see what they are going to give you for your crops this year.that is the reason corporation's do not like to invest in farming..to many variables in cost of production

[GliderGuider]

4. Corporations don't like to invest in farming???

What happened to all the family farmers in the developed world in the last 50 years, then? It's virtually all corporate farming now.

[madrchsod]

2. you really do not need charts to understand

there is no way bio mass is going to even come close to replacing oil. bio fuel/oils should be used for the production of grains..

[XemaSab]

5. Here's to ethanol:

the cause of, and solution to, all life's problems! :toast:

[GliderGuider]

6. Another way of looking at it

Replacing just 1% of the world's oil by crop biofuels would rob 750 million people of all their food.

[razzleberry]

7. do you really expect farmers to sell to the non-highest bidder? nt

[losthills]

8. Ethanol is a fraud,

pure and simple.

It's already raising the price of both corn and milk, and production of palm oil for biodiesel is already causing deforestation.

Many are concerned that global warming is going to cause food shortages, but we have politicians telling us that we're going to "get our fuel from the mid-west instead of the middle-east."

It's pie in the sky...