Study: better to burn biomass to power electric cars than to make ethanol
Corn ethanol promoters, get out your keyboards. You've got another dragon to slay. A new study has found that it is more efficient to straight-up burn plant material to generate electricity and then charge up electric vehicles than to make ethanol for those vehicles. Professor Elliot Campbell at the University of California Merced was lead author of a study that looked at the most efficient way to power transportation vehicles from biomass. The headline numbers: "biomass converted into electricity produced 81 percent more transportation miles and 108 percent more emissions offsets compared to ethanol."
"If you have a limited amount of land you're working with, and you want to squeeze the most transportation off that limited amount of land, then the electricity route makes the most sense," Campbell told NPR.
No one questions that an electric motor is way more efficient than an ICE for purposes of in-vehicle efficiency comparisons, but this study is not as cut and dried. Campbell and his co-authors did not look at the complete ecosystem (both natural and political) for ethanol and EVs; they simply tried to calculate "miles per area cropland" and greenhouse gas offsets when starting with both corn and switchgrass and ending with vehicles moving down the road. In this calculation, electric vehicles win.
Listen to a two-minute audio clip over on NPR and download the paper in PDF. Thanks to Bryant and Jason for the tips.
[Source: NPR, UC Merced]
Photo by net_efekt. Licensed under Creative Commons license 2.0.
Reader Comments (Page 1 of 2)
Prinn 1:06PM (5/08/2009)
DUH! im surprised there was a study necessary to figure this one out.
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Zeph 1:48PM (5/08/2009)
Common sense approach is to have both ethanol and electric options on the market, as electric is great for new cars, as batteries evolve, and ethanol is a simple conversion to internal combustion, environmentally sustainable (although some crops are better than others, hemp anyone?) and can use the existing fuel infrastructure as well as decentralize production to the family farms.
The real reasoning behind energy policy is corporations trying to build monopolies. In the interest of a prosperous middle class this has to be nullified and democratic energy policies need to be adopted at the local level. Electricity needs to be made from water, wind and solar and fuel needs to be made from ethanol, from whichever crop best fits the local ecosystem.
One study will never be definitive and chances are it will be corporately biased towards whoever, directly or not, paid for it.
Most people have learned not to give supposed "think tanks" more credit than they really deserve. Which is little to none.
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paulwesterberg 3:04PM (5/08/2009)
Plants are only about 6% efficient(max) at converting sunlight into sugars & cellulose. Modern solar panels are around 20% efficient(very expensive space panels are at 40%).
Ethanol must be distributed by truck or rail(there is no pipeline yet).
Electricity transmission loss is around 3%.
How you use the energy matters also. Internal combustion engines waste most of the energy as heat(75-80%) and use only 20-25% of the energy to move the car. Electric batteries and motors are around 85% efficient.
Corn yields 300-450 gallons of ethanol per acre. Sugarcane, about 550-850 gallons or so. Switch grass can theoretically yield over 1000 gallons per acre and algae 5000, although those numbers are likely to get way smacked down by reality (especially the algae numbers). But let's just go with them. CAFE average is ~24mpg, and you get way less mpg on ethanol, but hey, let's just say our flex fuel hybrid gets 40mpg. The average driver goes 12k miles per year, so corn can support 1.3 drivers/acre, sugarcane 2.3 drivers/acre, switch grass 3.3 drivers/acre, and algae a way-over-optimistic 16.7 drivers/acre.
A compact linear Fresnel reflector solar thermal generating station produces about 1MW nominal capacity for every 4 acres and has about a 20% capacity factor (in non-optimal sites). That's an actual MW per 20 acres, or 488,288,000Wh/acre-year. The Volt and Tesla Roadster both use about 200Wh/mi, so let's go with a more pessimistic 300Wh/mi after losses and with less efficient designs. That's 121.7 drivers per acre. I.e., it beats the pants off even the highly speculative numbers for algae. And it uses no water or fertilizer.
If you want land efficiency, converting the sun directly to electricity and using that electricity directly rather than having the intermediary stage of "plants" is the way to go.
Electricity wins.
Now if we can just get some affordable batteries and solar panels...
Zeph 3:07PM (5/08/2009)
No doubt... but the point is we can convert millions of cars to ethanol in one growing season, while the electricity, which could be better, still needs to get on the ground. One solution will lead to the other, what has to be done, asap, for any possible change, is to kill the energy monopolies, otherwise all you will have is plug in hybrids... if you're lucky.
required 1:18PM (5/08/2009)
You should really revise your headline so that it is more factual and not misleading. Perhaps something along the lines of, "Study: better to burn biomass to power electric cars than to make ethanol from corn". Reason being is that there are many very different ways of making ethanol.
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MT 2:03PM (5/08/2009)
Actually, from the study abstract...
"Here, we show that bioelectricity outperforms ethanol across a range of feedstocks, conversion technologies, and vehicle classes. Bioelectricity produces an average 81% more transportation kilometers and 108% more emissions offsets per unit area cropland than cellulosic ethanol."
It's not just corn ethanol they studied, but some of the "next generation" feedstocks as well.
required 2:24PM (5/08/2009)
Did you really bypass the term feedstocks? Again, the headline should be revised. Ethanol can be made many different ways from many different things. For example, it can be made from wood chips.
required 2:32PM (5/08/2009)
Another being the so called floating bioreactors that break down seaweed using enzymes. http://www.autobloggreen.com/2007/04/01/japanese-scientists-and-corporations-working-to-create-ethanol-f/
required 2:37PM (5/08/2009)
Wood is probably the best bet either way (burnt or ethanol) since the climate change has spurred so much timber devastation via the mountain pine beetle. There are literally thousands upon thousands of hectares of dead trees.
required 2:47PM (5/08/2009)
Oh and lets not forget or overlook ethanol from trash. This is often accomplished via solar power. Common trash, municipal waste into fuel. Ethanol fuel cells. What is not to love?
MT 2:53PM (5/08/2009)
The headline is fine because the study didn't look at just corn ethanol. They're
saying that REGARDLESS of feedstocks analyzed and used to make ethanol (corn,
switchgrass, etc), you're better off burning that to create electricity than turning it into ethanol. They use the term "celluslosic ethanol" in the abstract to indicate as such, as opposed to just corn ethanol. They also mention an average, meaning corn ethanol would have a worse showing than those average numbers, while something like switchgrass would be better than those average numbers. But that sentence quoted implies that in all the cases they looked at (corn, switchgrass, etc), bioelectricity outperforms ethanol. Otherwise "Here, we show that bioelectricity outperforms ethanol across a range of feedstocks, conversion technologies, and vehicle classes" would have to read something like "Here, we show
that bioelectricity outperforms ethanol across MOST feedstocks, conversion technologies, and vehicle classes."
So while the study may not have looked at EVERY possible ethanol feedstock, they apparently looked at more than just corn, and as such, it would be dumb for the title to specify "corn ethanol" when the study abstract clearly says "cellulosic ethanol".
required 3:10PM (5/08/2009)
No the headline in misleading. The fact remains that ethanol can be made from many things such as garbage via solar power.
required 3:19PM (5/08/2009)
Also, it appears that they just looked at ethanol combustion and overlooked ethanol fuel cells. So they are comparing burning corn to generate electricity (with a blind eye at the the injurious particulates involved) to power cars vs making ethanol to burn in combustion vehicles? That is daft from the get go and I would question the purpose of even putting the study on any pedestal. It's chock full of wacky bias.
required 3:39PM (5/08/2009)
Should I post more? Sure, why not.
The other important fact they gloss over is that society does not have a lot of electric cars. So they are suggesting that it is better to trash what we have and build new rather than retrofit or use existing vehicles. Question arises as to what or who exactly is the benefactor when they mention any level of betterment.
paulwesterberg 1:36PM (5/08/2009)
Breaking news - ethonol cars get really crappy gas mileage:
http://www.fueleconomy.gov/feg/compx2008f.jsp
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Zeph 1:48PM (5/08/2009)
After 911, mission accomplished, the economical figures, Obama's promises, I did not have sex with that woman, etc etc do you still believe what a .gov has to tell you?
If yes I have some prime Venusian real estate to sell you, with it's own water.
required 2:44PM (5/08/2009)
(even though it might look that way in this thread, I'm not a ethanol nut. I just want to cleanse some of the FUD) Bad mileage? How far you can go by introducing the least amount of Carbon into the environment. Biomass is a lot more carbon neutral than fossil fuels are.
paulwesterberg 2:49PM (5/08/2009)
Do you have a better source of standardized testing of fuel mileage? Ethanol contains less BTUs per volume than gasoline so it stands to reason that cars that burn it would get worse gas mileage.
Why would the epa fudge numbers on vehicle fuel mileage?
If anything I think they have gotten much more accurate at estimating real world mileage.
required 3:32PM (5/08/2009)
Paul, the EPA has a clear record (especially under the prior administration) of being highly devious, including their manipulative use of nomenclature, for example, they've used the term economy instead of efficiency. Now my comment to you was one of bringing this stat up a level by introducing how much carbon per mile. In other words, the comparison of fossil fuel mpg vs ethanol mpg is quite meaningless.
jcwinnie 2:16PM (5/08/2009)
Um, Seb, shouldn't the title read, Another study that shows bioelectricity is better than ethanol.
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