Biofuels provide less energy than their production requires.
#1
07-06-2005, 08:22 AM
Biofuels provide less energy than their production requires.
I expect this article to fuel the continuing controversy over bio-fuels, but it is an important contribution to this ongoing discussion.
A research article just published in a Springer Press research journal states that more fossil fuel energy is required to produce a given amount of bio-fuel than is contained in usable energy in said fuels.
The full reference is:
Ethanol Production Using Corn, Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower. D. Pimentel (Cornell University) and T.W.Patzek (UC Berkeley). Natural Resources Research, Vol. 14, No. 1, pp. 65-76, 2005.
I believe the article itself requires subscription, but the abstract is open to the general public:
Abstract:
Energy outputs from ethanol produced using corn, switchgrass, and wood biomass were each less than the respective fossil energy inputs. The same was true for producing biodiesel using soybeans and sunflower, however, the energy cost for producing soybean biodiesel was only slightly negative compared with ethanol production. Findings in terms of energy outputs compared with the energy inputs were: • Ethanol production using corn grain required 29% more fossil energy than the ethanol fuel produced. • Ethanol production using switchgrass required 50% more fossil energy than the ethanol fuel produced. • Ethanol production using wood biomass required 57% more fossil energy than the ethanol fuel produced. • Biodiesel production using soybean required 27% more fossil energy than the biodiesel fuel produced (Note, the energy yield from soy oil per hectare is far lower than the ethanol yield from corn). • Biodiesel production using sunflower required 118% more fossil energy than the biodiesel fuel produced.
(end abstract)
The article is very well written and provides an extremely intersting analysis, including a review of other recent reports and their divergent findings.
The authors clearly state that some recent reports have found negative energy return, while others have found positive return. The authors provide their own analysis, which is compiled from available and previously published data. They come to different conclusions from those reports stating positive energy return largely because they use a more comprehensive set of inputs (in other words, they consider a larger number of factors required for production that use energy).
For starters, the article refers to previous studies conducted by the US Dept of Energy, that suggest a negative energy return for bio-ethanol (ERAB 1980, 1981). Apparently, these reports were reviewed by a panel of independent experts, and the conclusions were found to be valid. A review conducted by one of the two authors here (Pimentel 2003) of those reports showing a positive energy return, indicated that in those reports many inputs (requiring energy for production process) were omitted.
Nevertheless, I feel that it is important to state that all of these reports and findings are based on estimates and have a range of errors in predicted outputs.
The authors also state that they did not consider all secondary environmental impacts in their evaluation.
The authors conclude that bio-fuel production results in a net negative energy return for a variety of reasons, and that photovoltaics are a more energy efficient way of converting energy from solar radiation.
Bottom line, this is very informative and important reading for those on this board who are interested in various alternatives to fossil fuel based energy production.
M
A research article just published in a Springer Press research journal states that more fossil fuel energy is required to produce a given amount of bio-fuel than is contained in usable energy in said fuels.
The full reference is:
Ethanol Production Using Corn, Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower. D. Pimentel (Cornell University) and T.W.Patzek (UC Berkeley). Natural Resources Research, Vol. 14, No. 1, pp. 65-76, 2005.
I believe the article itself requires subscription, but the abstract is open to the general public:
Abstract:
Energy outputs from ethanol produced using corn, switchgrass, and wood biomass were each less than the respective fossil energy inputs. The same was true for producing biodiesel using soybeans and sunflower, however, the energy cost for producing soybean biodiesel was only slightly negative compared with ethanol production. Findings in terms of energy outputs compared with the energy inputs were: • Ethanol production using corn grain required 29% more fossil energy than the ethanol fuel produced. • Ethanol production using switchgrass required 50% more fossil energy than the ethanol fuel produced. • Ethanol production using wood biomass required 57% more fossil energy than the ethanol fuel produced. • Biodiesel production using soybean required 27% more fossil energy than the biodiesel fuel produced (Note, the energy yield from soy oil per hectare is far lower than the ethanol yield from corn). • Biodiesel production using sunflower required 118% more fossil energy than the biodiesel fuel produced.
(end abstract)
The article is very well written and provides an extremely intersting analysis, including a review of other recent reports and their divergent findings.
The authors clearly state that some recent reports have found negative energy return, while others have found positive return. The authors provide their own analysis, which is compiled from available and previously published data. They come to different conclusions from those reports stating positive energy return largely because they use a more comprehensive set of inputs (in other words, they consider a larger number of factors required for production that use energy).
For starters, the article refers to previous studies conducted by the US Dept of Energy, that suggest a negative energy return for bio-ethanol (ERAB 1980, 1981). Apparently, these reports were reviewed by a panel of independent experts, and the conclusions were found to be valid. A review conducted by one of the two authors here (Pimentel 2003) of those reports showing a positive energy return, indicated that in those reports many inputs (requiring energy for production process) were omitted.
Nevertheless, I feel that it is important to state that all of these reports and findings are based on estimates and have a range of errors in predicted outputs.
The authors also state that they did not consider all secondary environmental impacts in their evaluation.
The authors conclude that bio-fuel production results in a net negative energy return for a variety of reasons, and that photovoltaics are a more energy efficient way of converting energy from solar radiation.
Bottom line, this is very informative and important reading for those on this board who are interested in various alternatives to fossil fuel based energy production.
M
#2
07-06-2005, 04:23 PM
Re: Biofuels provide less energy than their production requires.
Sad thing to hear, though i have recently read an article somewere that a new method of production that uses the entire plant produces a net gain. My assumtion is that they use the plant body in a compost pile to power a sterling engine and produce power and then use that compost as the fertalizer. Just an idea though. I'll be interested to hear more.
#3
07-06-2005, 06:38 PM
Re: Biofuels provide less energy than their production requires.
Biodiesel might have a valuable niche to replace sulfur as a lubricant in conventional diesel. Could we call this a "diesel hybrid fuel"? 
#4
07-07-2005, 12:01 AM
Re: Biofuels provide less energy than their production requires.
Hi Guys:
___I cannot prove it one way or the other but Ethanol via corn is energy positive by ~ 10% (1.1 to 1) according to the many articles written by the US research scientists that I have read. Ethanol via Switchgrass is energy positive to the tune of ~ 4 to 1 and Sugar Cane about 8 to 1. If you do not believe that the energy balance is positive, look up Brazil’s total fuel use vs. imported oil over the last 10 years. If Sugar Cane to Ethanol is not energy positive, Brazil has one heck of a neat perpetual motion - energy provider because they aren’t driving more automobiles using more fuel with less oil imports by magic?
___Good Luck
___Wayne R. Gerdes
___Waynegerdes@earthlink.net
___I cannot prove it one way or the other but Ethanol via corn is energy positive by ~ 10% (1.1 to 1) according to the many articles written by the US research scientists that I have read. Ethanol via Switchgrass is energy positive to the tune of ~ 4 to 1 and Sugar Cane about 8 to 1. If you do not believe that the energy balance is positive, look up Brazil’s total fuel use vs. imported oil over the last 10 years. If Sugar Cane to Ethanol is not energy positive, Brazil has one heck of a neat perpetual motion - energy provider because they aren’t driving more automobiles using more fuel with less oil imports by magic?
___Good Luck
___Wayne R. Gerdes
___Waynegerdes@earthlink.net
#5
07-07-2005, 12:38 AM
Re: Biofuels provide less energy than their production requires.
The question still remains about their use of fertilizer to grow the plants. That's not made from oil, but natural gas (methane) so if they are using it, then that needs to be calculated in. I don't know one way or another, but afik most industrial farming techniques use lots of chemical fertilizer as well as pesticides, herbicides etc that are made from oil, so any imports of those products should be counted as energy inputs too, but may not show up as oil importing.
I'm sure it's possible to produce a net energy gain using biofuels, but I think it would have to be done using natural / organic farming since a lot less energy is required as inputs. Industrial farming as it stands uses up 10 calories of energy for every one calorie of food produced, not including post-processing. Most of our food, and especially the stuff used to produce biofuels is made possible by the extensive use of oil and natural gas converted into various chemicals at an additional cost of energy in those processes. Many of the studies will not take these factors into account in order to come to the conclusion that the output is a net gain in energy. The details are very important when talking about net gains and losses.
I'm sure it's possible to produce a net energy gain using biofuels, but I think it would have to be done using natural / organic farming since a lot less energy is required as inputs. Industrial farming as it stands uses up 10 calories of energy for every one calorie of food produced, not including post-processing. Most of our food, and especially the stuff used to produce biofuels is made possible by the extensive use of oil and natural gas converted into various chemicals at an additional cost of energy in those processes. Many of the studies will not take these factors into account in order to come to the conclusion that the output is a net gain in energy. The details are very important when talking about net gains and losses.
#6
07-07-2005, 01:01 AM
Re: Biofuels provide less energy than their production requires.
Hi Schwa:
___I do not know all the details but Brazil plans on exporting ethanol in the very near future. What does that tell us?
___As far as Fertilizers and Herbicides, Switchgrass is one extremely hardy plant needing neither. Farmers plant it to separate their fields as well as prevent erosion at a fields edge/borders. I just do not know why ADM and Cargill are not taking that path instead of Corn based ethanol production given the energy balance? Something isn’t quite right about this situation unfortunately
___Good Luck
___Wayne R. Gerdes
___Waynegerdes@earthlink.net
___I do not know all the details but Brazil plans on exporting ethanol in the very near future. What does that tell us?
___As far as Fertilizers and Herbicides, Switchgrass is one extremely hardy plant needing neither. Farmers plant it to separate their fields as well as prevent erosion at a fields edge/borders. I just do not know why ADM and Cargill are not taking that path instead of Corn based ethanol production given the energy balance? Something isn’t quite right about this situation unfortunately
___Good Luck
___Wayne R. Gerdes
___Waynegerdes@earthlink.net
#7
07-07-2005, 04:24 PM
Pretty Darn Active Enthusiast
Join Date: Jan 2005
Location: Eastern Washington State
Posts: 443
Re: Biofuels provide less energy than their production requires.
Ok, here is the most simplistic comment of the afternoon, but with all this talk about hydrogen and how far off FCEV is, why aren't we seriously exploring alcohol powered internal combustion rather than chase after the moon? Sure, we will get to the moon, however in the meantime we have to have something reasonable to burn to move ourselves around and keep our lives intact.
#8
07-07-2005, 06:05 PM
Re: Biofuels provide less energy than their production requires.
There have been cars that run on alcohol (E85 specifically) for several years now. Because E85 is funded by government grants, it's in limited supply with very little motivation to really ramp up production. From what I've read, E85 won't be cost effective against gasoline with out government subsidies until gasoline reaches $3.50-$4/gallon. Even though many folks consider $2.50 gasoline expensive, in terms of real cost, it's still cheaper than all alternatives. Once gasoline hits $4/gal, then we'll see biofuels take off because they're finally financially viable without government assistance. The good news about E85 is that it burns imaculate compared to gasoline, so once we do make the switch, tailpipe emissions nearly vanish entirely.
#9
07-08-2005, 06:21 PM
Re: Biofuels provide less energy than their production requires.
Originally Posted by MGBGT
I expect this article to fuel the continuing controversy over bio-fuels, but it is an important contribution to this ongoing discussion.
A research article just published in a Springer Press research journal states that more fossil fuel energy is required to produce a given amount of bio-fuel than is contained in usable energy in said fuels.
The full reference is:
Ethanol Production Using Corn, Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower. D. Pimentel (Cornell University) and T.W.Patzek (UC Berkeley). Natural Resources Research, Vol. 14, No. 1, pp. 65-76, 2005.
A research article just published in a Springer Press research journal states that more fossil fuel energy is required to produce a given amount of bio-fuel than is contained in usable energy in said fuels.
The full reference is:
Ethanol Production Using Corn, Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower. D. Pimentel (Cornell University) and T.W.Patzek (UC Berkeley). Natural Resources Research, Vol. 14, No. 1, pp. 65-76, 2005.
Nevertheless ... there may be a bias by Dr. Pimentel and Patzek (heads the UC Oil Consortium at Berkeley) and there is also another side to their research and how it proceeds. Not being the science guru, I'll use someone else's discussion from a radio program (looking for the link) that had a 6 minute counter point and included a briefing on another site..
His (Dr. Pimentel) interview mainly focused on the ethanol side, but we focused on biodiesel of course and than we had 6 minutes to get our points across. Last night we were able to brief the host and provide him with both Pimentels full study and other objective materials. The host was thus able to ask some pointed questions.
One major flaw of Pimentels assertions, is that his studies assign all energy costs to components of the production cycle and do not discount those numbers for other materials produced in the process.
For example, in his soybean biodiesel chart, he stated that it takes 5,556 kg of soybeans to make 1,000 kg of oil. He assigns all of the energy cost of 7,800,000 keal (don't worry about this number it is a measurement like btu) for growing the soybeans to the soy oil. For an energy cost of $1,117.42 this is 92% of the final energy costs of $1,212.16.
Yet, 82% of those soybeans are reduced to soy meal, which he writes off as "soy byproduct waste". (Now we know better than that) This according to his numbers results in a net energy loss of 32% for the production of the soy biodiesel, because the "soy byproduct wastes" have no assigned energy cost. Yet in his text he allows that one can credit 2.2 million keal to the meal produced which will result in an energy loss for the final product of 8%. However, his posted table of energy inputs for soy do not include any energy credit for the meal.
Now if I were to use his same numbers, yet shift 82% of the energy costs to the soy meal. We would than have a net energy gain for the soy biodiesel of 40%.
This is just one example of how he is able to skew his studies conclusions by assigning energy costs as he sees fit.
In the studies conclusion, there is no mention of the numbers, just the statement that "...the oil extraction process for all oil crops is highly energy intensive as reported in this manuscript. Therefore, these crops are poor producers of biomass energy."
Hopefully a few of you can make some sense of this. I'm at a lost in determining why someone could actually justify bending reseach by factoring in 'soy meal' as waste or by product. In real life it is more than likely to be the opposite ... the soymeal (or whatever plant you use) is of more useful value than the oil being processed into fuel or cooking oil. That said, there are new techniques being used that grind the soy into flake and use far more of the plant to produce biodiesel ... not to mention the algae biodiesel under development.
One major flaw of Pimentels assertions, is that his studies assign all energy costs to components of the production cycle and do not discount those numbers for other materials produced in the process.
For example, in his soybean biodiesel chart, he stated that it takes 5,556 kg of soybeans to make 1,000 kg of oil. He assigns all of the energy cost of 7,800,000 keal (don't worry about this number it is a measurement like btu) for growing the soybeans to the soy oil. For an energy cost of $1,117.42 this is 92% of the final energy costs of $1,212.16.
Yet, 82% of those soybeans are reduced to soy meal, which he writes off as "soy byproduct waste". (Now we know better than that) This according to his numbers results in a net energy loss of 32% for the production of the soy biodiesel, because the "soy byproduct wastes" have no assigned energy cost. Yet in his text he allows that one can credit 2.2 million keal to the meal produced which will result in an energy loss for the final product of 8%. However, his posted table of energy inputs for soy do not include any energy credit for the meal.
Now if I were to use his same numbers, yet shift 82% of the energy costs to the soy meal. We would than have a net energy gain for the soy biodiesel of 40%.
This is just one example of how he is able to skew his studies conclusions by assigning energy costs as he sees fit.
In the studies conclusion, there is no mention of the numbers, just the statement that "...the oil extraction process for all oil crops is highly energy intensive as reported in this manuscript. Therefore, these crops are poor producers of biomass energy."
#10
07-09-2005, 04:46 AM
Re: Biofuels provide less energy than their production requires.
There may be some monetary value in soy meal, however I don't see how that can be included in the bio-diesel energy calculation since it isn't part of the product. If it's composted and used as fertilizer to reduce the input of chemical fertilizer to grow more soy, then that should be calculated, but that would have to be documented specifically, and if it were I don't see why they would ignore that factor since the amount of chemical fertilizer would be reduced, therefore it's included automatically in the cycle. If the energy content of the plant doesn't end up in the fuel, then it shouldn't be calculated as being part of the final product. If it's burned to heat the vats in the process, then it can be calculated, although the pollution caused by it's combustion should be noted as being part of the whole process too.
The problem with using soy is not so much the growing of it, as much as the processing of it. Extracting oil from soy beans is a mechanically intensive process that requires a lot of energy. The grinding and pressing machines are not running on wind or solar, yet...
There's a lot of room for improvement in the whole bio-fuels process, and I think that's what these studies should be highlighting rather than simply condenming the process completely. Organic farming uses far less petrochemical energy, and there are plants that produce much easier to extract oil than soy. But the real problem is scale. We are consuming so much oil (and the amount is still growing exponentially) that if it were to be replaced with bio-fuels we would need to have all the available farm land used to grow the fuel crops, never mind food crops. It's good to diversify in the fuel sector, I don't think any single source of energy is suitable for everything, as we are discovering with oil it's not good to put all the eggs in one basket, so it's good that r&d is being put into these processes, but I don't think it's wise to base the whole economy on it, but it makes an excellent transition tool as we move to more renewable energy.
The problem with using soy is not so much the growing of it, as much as the processing of it. Extracting oil from soy beans is a mechanically intensive process that requires a lot of energy. The grinding and pressing machines are not running on wind or solar, yet...
There's a lot of room for improvement in the whole bio-fuels process, and I think that's what these studies should be highlighting rather than simply condenming the process completely. Organic farming uses far less petrochemical energy, and there are plants that produce much easier to extract oil than soy. But the real problem is scale. We are consuming so much oil (and the amount is still growing exponentially) that if it were to be replaced with bio-fuels we would need to have all the available farm land used to grow the fuel crops, never mind food crops. It's good to diversify in the fuel sector, I don't think any single source of energy is suitable for everything, as we are discovering with oil it's not good to put all the eggs in one basket, so it's good that r&d is being put into these processes, but I don't think it's wise to base the whole economy on it, but it makes an excellent transition tool as we move to more renewable energy.
