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Not so green: corn ethanol reduces the soil carbon, increasing emissions and possibly contributing to warming. This effect is worsened if the leaves are removed for biofuel production, as some have suggested.  (Source: Don Hamerman)

Professor DeLucia of the University of Illinois and his colleagues have completed a massive new study, showing just how bad for the environment corn, and especially sugarcane, ethanol may be. It also shows grass ethanol can be very beneficial to cutting carbon, on the other hand.  (Source: Don Hamerman)

Replanting corn and sugarcane land with biofuel grass can help undo the damage done by these crops, the study suggests.  (Source: Don Hamerman)
A new study shows that switching from corn ethanol to grass may have great benefits

The ethanol business is a booming market, buoyed by several years of high gas prices.  While hampered somewhat by falling petrol costs, the market is seeing support from big investors like GM and is producing millions of gallons fuel yearly, with pumps expanding across the country.

However, while most agree that moving away from reliance on insecure, depletable oil is a good thing, there are also significant downsides to corn ethanol production, the current primary form of ethanol produced.  As discussed previously at DailyTech, corn ethanol is cited for higher food costs.  Additionally, it may not be as green from a carbon perspective as people think.

Companies like Coskata are looking to use alternatives such as quick growing grasses or wood waste to fuel their ethanol production.  Now a new study shows that not only does such production help to normalize food prices, it also helps cut down on excess atmospheric carbon.

A study from the University of Illinois confirms that some sources of biofuels can actually increase emissions of carbon dioxide, while others can decrease them.  The key is what you grow and where you grow it. 

The study compiled soil carbon information from dozens of other studies in order to get the big picture.  What it observes is that the amount of carbon that exists in the soil is increased by letting decomposing plant matter sit and eventually be absorbed into the earth, while tilling and plowing decreases the carbon in the soil, releasing it into the atmosphere.

Explains Evan DeLucia, a professor of plant biology at Illinois, "From the time that John Deere invented the steel plow, which made it possible to break the prairie sod and begin farming this part of the world, the application of row crop agriculture to the Midwest has caused a reduction of soil carbon of about 50 percent  The biggest terrestrial pool of carbon is in the soil. The top meter of soil holds more than three times the amount of carbon stored in either vegetation or the atmosphere, so if you do little things to change the amount of carbon in the soil it has a huge impact on the atmosphere and thus global warming."

Corn ethanol increases emissions, according to the study, because corn must be constantly replanted, and replanting requires tilling the fields.  Switchgrass, Miscanthus, and other fast-growing grasses, however, require no tilling and can grow wild, greatly increasing the soil's carbon and decreasing emissions.

Furthermore, these sources have more carbon density than corn, so once cost-efficient ways are created to process them, cellulosic ethanol should require much less land to produce than corn ethanol.

The study is significant, says Professor DeLucia as currently 20 percent of the U.S.'s corn crop goes to ethanol.  He describes "so we began with the hypothesis that it might be good for soil carbon to put a perennial biofuel crop on the landscape instead of corn."

From there they delved into massive amounts of information on soil carbon levels on land growing corn, sugar cane, Miscanthus, switchgrass and native prairie grasses, taking into consideration many factors.

They found that sugarcane, used greatly by Brazil's ethanol industry, is the worst offender when it comes to biofuels.  Sugarcane planted on native land slashes the carbon content, releasing vast amounts of carbon into the air.  Whereas perennial grasses add to soil carbon's base level each year, sugarcane land would require a century just to recover to the base level.

Corn showed similar, but lesser problems.  These problems could be alleviated somewhat by leaving more of the corn stover (plant waste) on the field, but the carbon was still cut significantly.

Losses from the initial planting of Miscanthus, switchgrass or native perennial grasses by on converted corn or sugarcane land took very little time to be neutralized thanks to great yearly gains in soil carbon.  Professor DeLucia states, "Consistent with our hypothesis, the perennial feedstocks like Miscanthus and switchgrass start building soil carbon very, very early on.  From a purely carbon perspective, our research indicates that putting perennial biofuel crops on landscapes that are dominated by annual row crops will have a positive effect on soil carbon."

These conclusions, he says, walk the study unintentionally "seems to walk you right into the food for fuel debate".  But he says that it just makes sense to plant grasses as biofuel feedstocks, even from a purely carbon-conscious perspective.

The research will be featured in the journal Global Change Biology Bioenergy next month.

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RE: Ethanol sucks
By Screwballl on 12/8/2008 1:36:28 PM , Rating: 2
Lets see, on several 2000+ mile road trips (yes 2000 miles, from Florida to South Dakota and back):

We had a 2001 Nissan Frontier which was gutless to begin with (2.5L V6) but at 20 mpg highway was not too bad... until we used E10 at which point it dropped to 14-15.5 mpg highway.

Or our 2001 Nissan Pathfinder with 3.1L V6 that saw 22-24 mpg highway dropped to 16mpg highway (and 12mpg city) when E10 was used.

With our current 2004 Durango with 4.7L V8 usually sees 15mpg (city) drops to 12-13.4 mpg when E10 is used. At 78K miles it runs fine as long as Ethanol is not used, but when we do, it stutters and feels like a gutless V6 in a heavy truck.

Oh and my 91 Suburban with 7.4L 454 V8 with TBI (work truck) usually sees ~12mpg city but with E10 it drops to 8.6-9.4 mpg. Also had to replace the TBI injectors and intank fuel pump a few thousand miles after using the E10 TWICE. Here it is at 164K miles and as long as I do not use Ethanol in any form in any of my vehicles, they run well, do not need unnecessary part replacements and get proper gas mileage.

TBI = Toilet Bowl Injection. TBI F-bodies sucked.

Only if they were not maintained properly.

And my parents 04 Hemi Durango has done over 80,000 miles using E10.

congratulate them... but also warn them that they will need some heavy engine work to be done around 100K miles, partly because these hemis are not known for reliability, but also because the ethanol is eating away at key components inside the engine, sensors and injectors. Chrysler did not start selling proper flex-fuel vehicles until the 2006 model year (which can handle the Ethanol properly).

As for other vehicles, remember that they may run fine for 50,000 miles or more. Someday take apart that Camaros TBI/Carb and just see how bad off it looks. The injectors/jets will be tarnished and partially gummed up. My neighbor and his 90 Camaro needed a total engine rebuild at 90,000 because everything was gummed up and oxidized from E10 usage in Alaska and North Dakota. He treats his car like his baby and takes very good care of it so maintenance is not an issue in most cases.

RE: Ethanol sucks
By FITCamaro on 12/8/2008 3:26:02 PM , Rating: 2
I'm not advocating E10. I'm just saying that personally, my vehicles haven't seen really any loss of mileage vs. EPA(in many cases I've gotten better but that's from how I drive). Or just over the years in general. I'd obviously prefer it to be gone but just haven't seen a problem.

TBI F-bodies sucked because they were dogs. The intake didn't flow at all. Putting a carb on a TBI engine gave a nice bump in horsepower and torque because of how restrictive the intake was. It was even worse than TPI in terms of flow. At least with TPI you got massive low end torque. TBI sucked across the entire rpm range. Not sure which was worse, TBI or CFI.

"So if you want to save the planet, feel free to drive your Hummer. Just avoid the drive thru line at McDonalds." -- Michael Asher

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