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July 12, 2005

What is Biodiesel's Energy Balance?

[RenewableEnergyAccess.com] Independent third-party, peer-reviewed studies show biodiesel has the highest energy balance of ANY fuel. A prominent USDA/DOE study shows for every unit of fossil fuel used to make biodiesel, 3.2 units of energy are gained in energy output. That's a 320% increase and includes soybean planting, harvesting, fuel production and transportation. For the full report, see the following link to download the report (.PDF).
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Reader Comments (7)
 
No image available
July 13, 2005
I'm not sure what this means from an environmental perspective.

Has anyone studied the emissions balance of burning enough fossil fuel to generate one unit of energy, plus enough biodiesel to generate 3.2 units of energy vs. simply burning enough fossil fuel to generate 3.2 units of energy?
Comment 1 of 7
No image available
July 21, 2005
You can consult our 2004 report on questions about the emissions of renewable fuels. Although the energy balance of biodiesel is OK, we think that it should only be made from waste oil and fat, as soy oil yields per hectare are so small that other options would yield far higher amounts of biofuels per ha. See
http://www.cec.org/pubs_docs/documents/index.cfm?varlan=english&ID=1561
Comment 2 of 7
No image available
July 23, 2005
In my humble opinion the best quality biofuel comes from virgin plant oils.

Biodiesel.org comments on the recent study regarding energy unit balance for biodiesel.

The recent study is apparently propaganda, not a peer reviewed study. It does not stand up to scientific scrutiny, as is generally the case with most propaganda.

I guess that means that biodiesel is seen as a potential threat by someone. I guess that's progress....
Comment 3 of 7
No image available
September 13, 2005
Looking into this further I have become quite confused. In any case I take back my previous comment.

I cannot rectify the statement on page 13 of the study: "One MJ of biodiesel requires an input of 1.2414 MJ of primary energy, resulting in a life cycle energy efficiency of 80.55%" with the summary's statement that "for every unit of fossil fuel used to make biodiesel, 3.2 units of energy are gained in energy output."

What am I missing?
Comment 4 of 7
No image available
September 13, 2005
Cornell scientists have come to a very different conclusion: "producing ethanol and biodiesel from corn and other crops is not worth the energy". Their findings are truly peer-reviewed (where peers are scientists) as opposed to this bit of propaganda (where peers apparently are other propagandists). See http://www.news.cornell.edu/stories/July05/ethanol.toocostly.ssl.html
Comment 5 of 7
No image available
January 31, 2006
A recent series of article in the journal Science makes it clear that Pimentel and co-workers are underestimating the energy balance for bioethanol by leaving out energy credits for animal feed. But to be really useful, cellulose needs to be part of the biofuel energy process

http://gmopundit.blogspot.com/2006/01/new-study-shows-biofuel-is-useful-and.html
GMO Pundit
Comment 6 of 7
No image available
October 3, 2006
Scott,
If you'll read on down to the next page in the report, you'll find this: "Table 125 and Figure 95 summarize the fossil energy requirements for the biodiesel life cycle. Because
90% of its feedstock requirements are renewable (that is, soybean oil), biodiesel's fossil energy ratio is
favorable. Biodiesel uses 0.3110 MJ of fossil energy to produce one MJ of fuel product; this equates to a
fossil energy ratio of 3.215. In other words, the biodiesel life cycle produces more than three times as
much energy in its final fuel product as it uses in fossil energy."

So your quote, the 1.2414 MJ number, includes the 90% renewable portion, which comes from the sun's energy input into the balance through photosynthesis.

Hope that helps anyone who may be confused.
Comment 7 of 7
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