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67 comments on Hard Look at Gov. Pataki Ethanol Proposal
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Ethanol is important for our energy future because it is the easiest fuel to substitute for gasoline for the 200 million existing gasoline-fueled vehicles in the USA. Existing autos built since 1995 can operate on ethanol concentrations of 20% or more without modification, and the first retrofit kits have appeared in the market to support operation on even higher concentrations of ethanol.
Biodiesel is especially important for support of diesel-powered agricultural equipment, in order to insulate farmers from petroleum price spikes.
But I'm game for more data on the subject. I just want to make sure we do the EROEI analysis before investing huge sums of money into that instead of electric plug-ins based on wind/solar/other. Or just simply investing in greater conservation.
What other studies would you recommend on the subject of ethanol EROEI using corn or cellulose based feedstock?
And I completely agree about ethanol powered farm equipment. We need a whole system that is fossil-fuel free, not just a system that uses lots of fossil fuels inputs and produces another type of liquid fuel output.
There is a 2004 paper by Lynd & Wang of Dartmoth published in the Journal of Industrial Ecology (an MIT and Yale publication)showing EROEI for corn and cellulosic biomass in different types of process configurations. To tie everybody in the paper was guest edited by an Iowa State University Engineering person. They were very thorough in identifying the energy inputs from fertilizing the crop all the way through crop handling, enzyme treatment and cogeneration in the ethanol plants. They show positive EROEI for most processes. Yes, corn can result in negative EROEI if set up indcorrectly and yes cellulosic can be better in some configurations. But corn and cellulosic are about equal if configuring ideally for the respective feedstock. The key is you can't set up one type of operation and then change feedstock or process parameters. No one size fits all. Physical plant construction is critical to positive EROEI. Sounds a lot like refineries and sour crude issues we discuss here all the time.
There have been enormous strides made in industrial enzymes for ethanol production. This has been led by Novo Nordisk but others are working hard in that area. The enzymes are required to lower the energy cost to breakdown the complex molecules into sugars that yeast can convert to ethanol. As I posted earlier today there are also growing markets for the edible waste from the ethanol processors, particularly distillers grain from corn. Not only have the EROEI been shown to be positive there are very strong economic incentives to cycle corn through ethanol plants before feeding animals.
The point of all this is that old data in the biofuels area is not to be trusted. People are figuring out how to get positive EROEI in a sustainable way. I sometimes wonder if the scrutiny applied to biofuels was used for petroleum from exploration to wells through refining to cleanup and waste disposal what the true EROEI would be. Those considerations are typical for evaluating ethanol.
Personally, I think biodiesel has a place - as fuel for planes, say - but cannot replace gasoline for cars. Post-peak, we are going to have trouble growing enough food for the current population of the U.S. Biofuel will be a luxury.
I agree that celluslosic ethanol has its place, as does sugar cane and a few of the biodiesels, but all of these solutions only go so far, and leave me with the following impressions:
1)The latent power in crude oil compared to alternatives is awesome. Until I really dug into this research and looked at the scale of alternatives, I didnt internalize how ginormous our energy subsidy really is...
Yes Pimentel has been discredited: by the Ethanol Lobby, but not yet by science.
The US gasoline consumption is 9.5 million barrels / day, 9.5 * 365 * 42 = about 145 billion gallons annually. The US annual corn crop harvest is 10 billion bushels. 10 * 2.5 = 25 billion gallons of ethanol. Ethanol yield is about 2.5 gallons per bushel. 25 / 145 = about 17% If we used the entire annual corn crop to produce ethanol, 10% could be used for gasohol while the other 7% would be consumed by increased demand before the new ethanol plants came on line.
In addition to corn I have been looking at some numbers on soybeans and potatoes.
The US harvests about 2.5 billion bushels of soybeans annually, and about 23 million tons of potatoes. Potatoes yield about 25-30 gallons of ethanol/ton or 688 million gallons of ethanol about .5% of our gas consumption.
There has been much talk about bio-diesel from soybeans. The only numbers I can find are that soybeans yield about 9.5 to 10 pounds of oil/bushel. How much bio-diesel will 10 pounds of soybean oil yield?? 1.5 Gallons max, that would make 3.75 billion gallons of bio-diesel. Our annual distillate consumption is 4.5*365*42=69 billion gallons. Soybean bio-diesel would only supply 5.4% of our distillate needs. 3.75/69=.0543.
There is another problem with bio-diesel. Currently an average to excellent soybean yield is about 50 bushels/acre. At $6.00 a bushel that is a $300 annual/acre crop, However at best it will yield about 75 gallons of oil and 60 gallons of bio-diesel. That means with zero capitol and processing expense, the bio-diesel has a crop cost alone of $5.00 per gallon.
I understand that Minnesota has enacted a 2% bio-diesel law that requires nearly all diesel fuel to be blended with 2% bio-diesel. Now I don't know how much nearly is, but here is a web-site to explain it further.
http://www.mda.state.mn.us/biodiesel/b2/default.htm
Here is a web-site of oil yield for oil-bearing crops.
http://journeytoforever.org/biodiesel_yield.html#ascend
Here is a more efficient method of consuming corn. 15% water in shell corn contains 7000 btu's of energy per pound, and 15% shell corn weighs 56 Lbs per bushel. That is 392,000 Btu's per Bushel. At $2.00 per bushel that is $5.10 per million Btu's. Then I checked kerosene it's about the same as distillate. 6.819 Lbs per gallon and 19,810 Btu's per pound or 135,000 Btu's per gallon, or 7.4 gallons per Million Btu's. At $1.76 per gallon that is $13.00 per million Btu's. NG spot today was about $10.00 per million Btu's. Now according to the USDA a bushel of 15% corn should yield 2.68 gallons of ethanol,and ethanol contains 14,000 Btu's per pound and weighs 6.59 Lbs per gallon. That means that a bushel of corn will yield 247,000 Btu's, so you see you lose 145,000 Btu's in the ethanol process, however the leftover mash is used for cattle feed. I don't know the efficiency of a corn burning stove versus a gas or fuel oil furnace, however it is certainly more efficient than using it to produce ethanol, as a significant amount of energy is used in the conversion process. Corn burner web sites.
http://www.bae.umn.edu/extens/ennotes/enaug01/burncorn.htm
http://energy.cas.psu.edu/shellcorn.html
http://www.breitbart.com/news/2005/12/09/051209141924.flu6l9pn.html
How much food value does ddg have after 65% of the energy has been removed?