By all accounts, biofuels deliver startlingly modest reductions in greenhouse gases. In a relatively generous assessment of the environmental benefits of ethanol and biodiesel released last year, University of Minnesota researchers credited corn-based ethanol with 12 percent less net greenhouse-gas emissions than gasoline, while finding that soy-based biodiesel emits 41 percent less.
But here's the catch: It takes so much corn to produce a gallon of ethanol, and so much soy to produce a gallon of biodiesel, that the net GHG advantages are likely to be almost nil. The U of Minn researchers write [emphasis mine]:
[I]f one replaced a total of 5 percent of gasoline energy with ethanol energy, greenhouse gas emissions from driving cars would be a bit more than a half percent lower (5 percent times 12 percent).
Whoa. In 2006, U.S. ethanol producers burned through 18 percent of the corn harvest to offset 3 percent of gasoline use. What the Minnesota study is telling us is that we could increase corn ethanol production by two-thirds (to achieve a 5 percent offset) -- burning through 40 percent of the corn crop -- and still only reduce greenhouse gas emissions by just a bit more than a half percent.
By my calculations -- based on 2006 output of 4.8 billion gallons of corn ethanol -- it would take about 8 billion gallons to achieve that 0.5 percent drop in GHG emissions. Ethanol production is subsidized by a dizzying array of public programs; the most direct one is the $0.51 per gallon blender's tax credit for using the stuff.
To gain that razor-thin GHG advantage, the Treasury would be out some $4 billion ($0.51 times 8 billion) per year, just from that one form of public support. This is sound public policy? In a rapidly warming world, dropping $4 billion on corn ethanol seems clinically insane as a strategic use of the public purse.
And -- finally coming to the point of this post -- a new study [PDF] has emerged declaring that even that comically paltry GHG benefit may be spectral. Biofuel use may actually increase GHG emissions.
The study, published in the journal Atmospheric Chemistry and Physics, was performed by American, German, and British researchers, and included the Nobel laureate Paul Crutzen. I have no information on funding.
It claims that biofuel production emits far more nitrous oxide, a greenhouse gas some 296 times more potent than carbon dioxide, than has normally been assumed.
The source is artificial fertilizer, a potent source of nitrogen. When farmers apply it to soil, a certain amount of it -- between 3 percent and 5 percent, according to the study -- enters the atmosphere as nitrous oxide.
In our email exchange, the University of Edinburgh's Keith Smith, one of the study's authors wrote that, "if you increase the inputs of [fertilizer] through expanding biofuel production, you can expect more N2O [nitrous oxide] pro rata."
As a result, corn-based ethanol releases, at worst, 50 percent more GHGs than conventional gasoline, the study concludes. At best, corn ethanol emits 10 percent less GHGs than gasoline, or less than half of the advantage (22 percent) calculated by the U of Minn researchers.
Biodiesel from rapeseed -- the preferred feedstock in Europe -- is even worse, the study says. It releases as much as 70 percent more GHGs than conventional fuel. Ouch.
I asked Smith precisely how his study's methodology differ from that of the U of Minn researchers. He replied:
Assessments like this one you mention are calculating the net gain when the fossil fuel energy needed to produce a biofuel is subtracted from the energy value of the fuel -- as your figures show, 78% (i.e. 100-22%) or 59% (100-41) of the "gain" is cancelled out by these energy costs. Our assessment of the global warming implications is largely additional to these considerations, becasue most assessments hitherto have ignored the N2O emission issue, or only allowed for PART of it -- we have caclculated a bigger percentage conversion of fertiliser N to N2O than previously accepted.
Smith's study claims that cellulosic ethanol made from agricultural "wastes" -- e.g., Archer Daniels Midland's big plan to use "corn stover" -- would "cause unfavourable or low-gain impacts on climate." Cellulosic ethanol from switchgrass and other perennial grasses would be much better, though, the report states.
Even so, as I reported a couple of weeks ago, the USDA -- cellulosic ethanol's research great sponsor -- is becoming increasingly dubious about the viability of cellulosic technology.
Ask Umbra on green moving companies
Et tu, Al? Franken gulps the ethanol-spiked Kool-Aid
Comments
View as Flat
GreyFlcn Posted 6:56 am
25 Sep 2007
You think thats scary
You think thats scary.
I'd look more towards these studies which focus on the N2O aspect (Which the Federal Studies practically ignore)
http://greyfalcon.net/lcarough7.png
http://greyfalcon.net/n2o.png
http://greyfalcon.net/n2ostudy.png
_
Then you get in to the indirect emissions caused by palm oil, and soybeans. (And corn)
http://greyfalcon.net/soy
http://greyfalcon.net/palmoil
http://greyfalcon.net/soy2
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GreyFlcn Posted 6:57 am
25 Sep 2007
Whups
You got into the n2ostudy.png thing later in your comments :P
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Erik Hoffner Posted 7:06 am
25 Sep 2007
biodiesel from waste
I know that you're talking about crops to fuel here, but using waste vegetable oil for biodiesel is a fine idea, and is a greenhouse gas saver. I know, we can't collect enough used oil to make enough fuel to make a big enough dent, but we can make something of a dent, and we should. Every town and city can have its own biodiesel reactor.
The Orion Grassroots Network: 1,100+ grassroots groups working for conservation & more
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GreyFlcn Posted 7:47 am
25 Sep 2007
Lets put it this way
We can only meet less than 1% of our needs with waste vegetable oils and waste animal fats.
Considering the DAMAGE causes by all the other biofuels, I'd prefer we swear off it entirely, rather than quible over the merit of a few drops.
_
That said, this particular study does let elephant grass (mithcansus) off the hook.
Catch being, as Tom mentioned, Cellulosic stuff is pretty unlikely any time soon.
_
That said, another scary thing about Algae.
ONLY if it is grown in an enclosed area, with intensive water recycling, would it not be a problem.
If it was open pond growth, not only would the algae strains get infected with other varieties of algae. But it would require tons of water due to evaporation, and it would result in tons of N2O emissions.
Catch there being that scaling up enclosed algae in a cost competative manner is also highly unlikely.
http://greyfalcon.net/algae
http://greyfalcon.net/algae2
_
When it all comes down to it, Photosynthesis is a very inefficient way to harvest sunlight as energy.
http://greyfalcon.net/sugarsolar
http://greyfalcon.net/ethanol.png
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justlou Posted 8:23 am
25 Sep 2007
Show Me the Mileage
Any actual petroleum offset gained by ethanol may be zeroed out by the lower mileage in vehicles burning it. So after all this what have we actually gained?
We are pulling our collective paddle through the water without actually moving the boat forward. The evidence is showing that we are moving backwards and drifting downstream toward the falls. But proponents will tell us the scenery is still looking good.
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Erik Hoffner Posted 9:28 am
25 Sep 2007
less than 1%
Grey, hey, even so, around 1% is a lot of energy, when you're talking about the world's gas hog, the US. Still sounds good to me, and if it gives towns and cities, who run their fleets on the diesel engine, a measure of locally produced fuel, there's no harm.
The Orion Grassroots Network: 1,100+ grassroots groups working for conservation & more
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Biodiversivist Posted 9:36 am
25 Sep 2007
I'm with, Erik
People who have found a source of biodiesel made from waste oil are about as carbon neutral as you can get, assuming of course that the waste oil was not going to be recycled by another user for another purpose who must now turn to virgin oil(leakage). Sigh... no easy answers.
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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Biodiversivist Posted 10:56 am
25 Sep 2007
When you add the Science article
which also shows that these fuels are worse than fossil fuels, but for different reasons, you start to get the impression that humanity really may not be smart enough to get out of this one.
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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GreyFlcn Posted 11:19 am
25 Sep 2007
Quibling over drops
Perhaps, but you have to take in the "aggregate effect" of it.
We would have less greenhouse emissions total if we swore off biofuels entirely.
_
That said, thats not entirely going to happen anyways.
But consider this, we could save 3% of our fuel use merely by inflating our tires better.
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GreyFlcn Posted 11:24 am
25 Sep 2007
That said
Imagine for instance that that waste grease was used for other purposes.
For instance as lubrication grease.
http://www.soynewuses.org/ProductsGuide/Industrial_Indust ...
Or better yet, having it run an electricity turbine at more than double the energy efficiency.
http://greyfalcon.net/biodiesel.png
http://media.cleantech.com/376/chevron-turning-california ...
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Erik Hoffner Posted 11:38 am
25 Sep 2007
grease
Sure, you can use grease in different ways than making it into biodiesel like burning it straight in a cogen/turbine. But the diesel engine isn't going away any time soon, and the emissions profile of biodiesel is better than diesel on almost every account but NOx, so I'd rather have that in my kid's school bus, wouldn't you?
And just in this area, it's common knowledge that restaurants flush their fryer fat down the drain rather than pay to have it collected. It's a huge problem for wastewater treatment plants, as oil is tough to deal with. So I think we could do a much better job of collecting what's out there.
The Orion Grassroots Network: 1,100+ grassroots groups working for conservation & more
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GreyFlcn Posted 11:52 am
25 Sep 2007
Depends
Diesel fuel no longer contains sulfur.
It's becoming manditory for new diesel vehicles to have particulate filters. And there's a retrofit program which offers free federal funding for particulate filters on school buses.
That said, that NOx you are talking about, creates Ozone. Which is a primary component of Smog formation. And a greenhouse gas itself.
_
Frankly if we're talking school bus fleet vehicles. The best thing they could do is to convert them to run on natural gas.
It's cheaper, cleaner, and has the lowest greenhouse emissions.
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Erik Hoffner Posted 12:57 pm
25 Sep 2007
sulfur
Grey, there's nothing on that page about sulfur: is that the link you meant?
But you can't say that diesel has no sulfur in it. Right now Low Sulfur Diesel is on the market, and there are regs coming down mandating Ultra Low Sulfur Diesel for most engines by 2010. But some of the biggest end-users won't even be required to sell it:
By contrast, biodiesel contains no sulfur at all. It's cleaner in every category but NOx.
Erik
The Orion Grassroots Network: 1,100+ grassroots groups working for conservation & more
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Rural Populist Posted 2:39 pm
25 Sep 2007
Fossil fuels have externalities too
This entire debate is immensely complex, and I don't mean to take one side or the other by saying this, but if we are going to search high and low for all the possible external greenhouse gas contributors associated with biofuels (a fair thing to do), it seems like we ought to do the same for fossil fuel before making comparisons.
I wonder just how much the U.S. military contributes to global warming with all of their antics designed to make the world safe for oil exploration.
Also, Tom, your headline (Biofuel: Is it a greenhouse gas, gas, gas?) is a bit sweeping. Perhaps "Corn Ethanol: Is it a greenhouse gas, gas, gas?" would be more appropriate.
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GreyFlcn Posted 2:50 pm
25 Sep 2007
Heh. Not broad enough.
It's not that un-sweeping though.
Practically the only biofuels which survive are:
- Cellulosic High Growth Grass
- Cellulosic High Growth Trees
- Theoretically, enclosed Algae production
- Waste vegetable oil, etc
- Waste paper mill pulp, etc
_So something along the lines of 99% of all biofuels produced today are bad.
So I guess thats not "all biofuels".
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Biodiversivist Posted 2:51 pm
25 Sep 2007
Actually,
according to the two recent studies, corn, sugarcane, soybeans, rapeseed and a whole host of other biofuel feed stocks are worse than fossil fuels as far as GHG is concerned. Palm oil, the worst of them all, interestingly enough isn't mentioned in either study.
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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GreyFlcn Posted 2:59 pm
25 Sep 2007
Actually
Actually palm oil is mentioned in the study.
The study gives it a slight net positive.
Although thats only in direct emissions.
If you factor in INDIRECT emissions then it's absolutely horrible.
http://greyfalcon.net/palmoil
_____
As for the ULSD aspect, it's a bit more complex than that.
Over 80% of diesel fuel must be ULSD.
http://www.clean-diesel.org/highway.html
And it's a federal crime to sell the old type of diesel to cars with a model year 2007 or newer.
http://www.clean-diesel.org/images/DPLabelFacts121406.pdf ...
It's a bit more than "completely optional"
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biofuelsimon Posted 11:56 pm
25 Sep 2007
Its a gas gas gas
Thirsty autos. The more I write about biofuels the more I am convinced that there is an elephant in the room that no one is acknowledging. The elephant is automotive fuel economy. There is no point using expensive grain to make a gasoline extender if its just going to poured into inefficient autos and burnt. Robert Rapier said at the end of last year fuel ethanol is linked boondoggle.
That doesn't apply to all biofuels, but when the volume of corn needed to produce a tank of gas could feed a man for a year, you have to wonder where people's priorities are...
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Biodiversivist Posted 1:22 am
26 Sep 2007
I'm with biofuelsimon
Using an acre of land to grow a months worth of biodiesel for an SUV or pickup truck that has an engine that converts maybe 18% of the fuel's energy into work is insane. We should be promoting efficiency.
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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bryankwalton Posted 1:33 am
26 Sep 2007
And we should be taxing the hell out of fuel.
And we should be taxing the hell out of fuel. Until we make fuel more expensive so that we have a disincentive to drive more, we will never fix the problem. We need a steep gas tax.
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wyrick Posted 1:42 am
26 Sep 2007
Missing the Point
I'm not going to argue against the fact that the current state of biofuel production in this country gives us marginal environmental gains at best. As a biofuels advocate myself I am fully honest that it is NOT a solution to our problems in any respect.
The hardest part of changing to renewable fuels is not technology, but mindsets of the public at large. Technology and research will keep advancing even in the extremely complex topic of life cycle GHG emission analysis. The use of any alternative to petroleum at this point is as much about changing status quo as it is the new technology.
The elephant in every room regarding energy use is efficiency. It's not the most glamorous solution but it is the cheapest, cleanest, and most immediately available option we have.
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Jon Rynn Posted 2:00 am
26 Sep 2007
On elephants...
...if vehicle-miles-travelled-per-year keeps going up, and greater efficiency would probably send those miles up even more, the growth in miles-travelled will cancel out the efficiency. Ultimately, people will have to deal with the elephant, and the unicorn too -- by which, if I'm not mangling my metaphors, I mean public transportation. It's the only way to avoid a rush to biofuels, coal-to-liquids, etc.
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GreyFlcn Posted 2:00 am
26 Sep 2007
Obvious losses.
No. It's not "marginal gains".
It's "significant losses" in the best case.
It's "HUGE losses" in the worst case.
_
And yes, if you take coal-to-liquids, hydrogen, and biofuels out of the equation, then it's ALL about energy efficiency.
_
Switching fuel types at that point is merely for compatibility purposes.
Conventional Engine, 20% energy efficiency
Diesel Engine, 40% energy efficiency
Gasoline-Hybrid Engine, ~50% energy efficiency
HCCI Engine, ~55% energy efficiency
Electric Engine, 80-90% energy efficiency
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Jon Rynn Posted 2:39 am
26 Sep 2007
So electric vehicles...
...are the only kind of automobile that makes any kind of sense, because the increase in miles-travelled will eat up efficiencies in any other engine type
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GreyFlcn Posted 3:34 am
27 Sep 2007
Well more than that
Not just per capita vehicles miles traveled, but total vehicle miles traveled are expected to double by 2025.
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Meagan Posted 10:24 pm
01 Oct 2007
Stop screwing around.
We need to stop messing around with biofuels etc., and get the hydrogen cell out there.
You mut be the change you wish to see in the world. -Mahatma Gandhi
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vortex Posted 11:51 pm
01 Oct 2007
Social Problems of Biofuel
I think it's also very important to realize that if we're talking corn biofuel, that corn is coming from Mexico. Now, when there is a surplus on corn there, the price goes up. I forget all of the places I have read about this problem, but currently many in South America who have less money are unable to purchase their staple food due to America's use for fuel as well as those plastic silverware that are made of corn.
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Philip S Wenz Posted 8:51 am
19 Nov 2007
Cars Drive Themselves Around!
Something to keep in mind about cars is that they are the LEAST efficient mode of transportation, and that will never be fixed no matter what kind of fuel they use. The reason is simple -- cars spend most of their energy driving themselves around.
Say you weigh 125 pounds and your two kids combined weigh 75 pounds, so your car's human cargo is 200 pounds. But the car weighs, say, 4,000 pounds. When you're going down the road, 5% of the fuel burned is moving your family, 95% is moving the car!
The ratio can get a little better, but I doubt that any people-to-car weight ratio could get better than 25/75. What we need is public transportation -- more people, less vehicle.
Philip S. Wenz, Editor, Ecotecture.com
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