Food vs. fuel no image

Published on December 3rd, 2008 | by Nick Chambers

13

Ethanol Made From Grasses Reduces Greenhouse Gases


If non-food cellulosic ethanol — “celluline” — is the future of sustainable biofuels, what are the best non-food crops to use to make it?

In a new study, researchers have shown that growing perennial grasses to make celluline rather than using corn stover or sugar cane is better for the environment because it increases soil health and stores much more carbon in the soil, thereby reducing greenhouse gases.

[social_buttons]

Current first generation ethanol is produced by fermenting the starch in corn kernels. This has become a controversial source of biofuel due to food vs. fuel concerns and the relatively low energy gain from the whole process.

But celluline represents a true departure from these concerns in that significantly more liquid fuel energy can be harvested from non-food portions of the plant — the stems and leaves. Celluline is still in the research and development stage, but many people have hung their hats on it as the holy grail that will replace corn ethanol and bypass concerns over food vs. fuel and energy gains (PDF).

Many researchers suggest that, as a source of celluline, we can still use corn, only we would use the whole corn plant instead of just the starch from the corn kernel. But researchers at the University of Illinois have found that even if we were to use the whole corn plant as a source of biofuel, it may be much better to use perennial grasses instead.

As a bit of a refresher: plants use the sun’s energy to convert carbon dioxide from the atmosphere into various plant parts such as leaves, stems, and roots. A large portion of the carbon in the leaves, stems and roots eventually ends up as organic carbon in the soil (roughly 5% of a healthy soil is organic carbon).

The organic carbon in soil is a major sink of carbon dioxide from the atmosphere. Whenever the soil is worked due to farming, construction, gardening or anything else, some of this carbon returns to the atmosphere in the form of carbon dioxide.

The problem with using corn, and other annual crops such as sugarcane, is that they need to be replanted every year. This repetitive working of the soil creates a carbon deficit that can take years to build back using the best management strategies available and in the meantime you’ve released more carbon dioxide into the atmosphere than you’re trying to save by using biofuels in the first place.

On the other hand, the researchers found that perennial grasses like miscanthus, switchgrass and native prairie grasses, have a small initial carbon release associated with planting, but after that they start acting as a carbon sink very quickly.

So, in terms of dealing with climate change, if we’re going to turn to biofuels as part of our energy mix in the future, it looks like perennial grasses are the hands-down winner.

Image Credit and Source: EurekAlert!

The findings from this study will appear next month in the journal Global Change Biology Bioenergy.



MAKE SOLAR WORK FOR YOU!





Next, use your Solar Report to get the best quote!

Tags: , , , , , , , , , , ,


About the Author

Not your traditional car guy.



  • Cameron

    Perennial grasses have the added benefit of holding the soil together, so that when the spring rains come the soil doesn’t wash away.

    Taking the entire corn plant is problematic. Preventing some loss of soil organic matter can be managed by plowing down residues. By taking the entire plant farmers would be even more dependent upon artificial fertilizers to maintain productivity.

    Despite the apparent advantage perennial grasses have over corn for ethanol production I am still quite skeptical. I hear a lot of lip service by ethanol producers and scientists about corn being a ‘gateway’ feed stock – but see very little tangible evidence of a developing alternative.

    Perhaps if congress got rid of any and all corn/ethanol related subsidies this industry would get serious about finding actual alternatives that make sense. I’m not holding my breath.

  • Cameron

    Perennial grasses have the added benefit of holding the soil together, so that when the spring rains come the soil doesn’t wash away.

    Taking the entire corn plant is problematic. Preventing some loss of soil organic matter can be managed by plowing down residues. By taking the entire plant farmers would be even more dependent upon artificial fertilizers to maintain productivity.

    Despite the apparent advantage perennial grasses have over corn for ethanol production I am still quite skeptical. I hear a lot of lip service by ethanol producers and scientists about corn being a ‘gateway’ feed stock – but see very little tangible evidence of a developing alternative.

    Perhaps if congress got rid of any and all corn/ethanol related subsidies this industry would get serious about finding actual alternatives that make sense. I’m not holding my breath.

  • http://globalpatriot Global Patriot

    Regardless of the “best” method of producing ethanol, the ultimate solution will be a mix of plants based on benefit to the environment – which will be different between regions.

    The big mistake is to assume that one solution is best for all places, then mandate that solution, only to deal with the negative consequences down the road.

  • jpm100

    A little off-topic, but the fate of ethanol as fuel is going to get a set back without the Big 3. And if they survive, doing anything outside of immediate product, like roadmapping the fleet to ethanol, probably will be pushed off the table.

    I’m not sure the Japanese have any E85 vehicles that are not big Truck/SUVs. Imho, they are being drug into ethanol. Without US competitors pushing for ethanol, the imports will be less likely to want to do anything that isn’t roadmapped in their home market. Is Japan going to ethanol?

    If they aren’t or are behind the US, I suspect instead having some vehicles and no infrastructure, we’ll move to a phase where we have the infrastructure and no vehicles.

  • jpm100

    A little off-topic, but the fate of ethanol as fuel is going to get a set back without the Big 3. And if they survive, doing anything outside of immediate product, like roadmapping the fleet to ethanol, probably will be pushed off the table.

    I’m not sure the Japanese have any E85 vehicles that are not big Truck/SUVs. Imho, they are being drug into ethanol. Without US competitors pushing for ethanol, the imports will be less likely to want to do anything that isn’t roadmapped in their home market. Is Japan going to ethanol?

    If they aren’t or are behind the US, I suspect instead having some vehicles and no infrastructure, we’ll move to a phase where we have the infrastructure and no vehicles.

  • Tom

    A very long time ago (the 1970’s), my father said that studies long before that, suggested that Kudzu vine (an invasive species that occurs widely in the US) could be used for cellulosic enthanol. Kudzu will grow in almost any soil and can grow a foot a day. It basically covers anything in the Southeast that can’t run away. It also restores the the Nitrogen content of the soil. Harvesting fast-growing invasive species would seem preferable to using either fertilized crop species or slow-growing native species.

  • Tom

    A very long time ago (the 1970’s), my father said that studies long before that, suggested that Kudzu vine (an invasive species that occurs widely in the US) could be used for cellulosic enthanol. Kudzu will grow in almost any soil and can grow a foot a day. It basically covers anything in the Southeast that can’t run away. It also restores the the Nitrogen content of the soil. Harvesting fast-growing invasive species would seem preferable to using either fertilized crop species or slow-growing native species.

  • Steve-O

    Yeah I say rule out nothing. I have heard that hemp is great as well for celluline and bio-D. Doesn’t deplete the soil.

  • Steve-O

    Yeah I say rule out nothing. I have heard that hemp is great as well for celluline and bio-D. Doesn’t deplete the soil.

  • Doug

    Yeah this stuff is pretty great; you can drive 200 miles then get stoned to the bejesus off of it.

  • Doug

    Yeah this stuff is pretty great; you can drive 200 miles then get stoned to the bejesus off of it.

  • LonnieB

    Ahhh! At last! A post about alternative palnts for the production of ethanol, or “celluline”, as Nick would have it.

    JERUSALEM ARTICHOKES!!!!

    It is a weed that grows all over central North America all by itself, and can be grown practically anywhere else, from the rich plains of Illinois to the poor soils of Wyoming. It can be grown on land most farmers would scoff at. Being native to this continent, it is immune to just about every bad bug and spore America has to offer.

    Properly (& extrememly easily) cultivated, it can produce as much as 15 tons of tubers per acre, yielding approximately 1,200 gallons of ethanol per acre (if my memory serves me, corn is around 400 g.p.a.).

    Even though it is a delicacy, especially in France (they eat anything), it is not a food commodity crop, so it doesn’t take porage away from the starving Ethernopians.

    In fact, it can be used as feedstock for cattle as well as ethanol distilation, both first and second generation processes.

    It contains carbohydrates called Inulins, and cannot be fermented using regular Brewer’s yeast. But suing other starins of yeast such as Kluyveromyces fragilis, Kluyveromyces marxianus, Torulopsis colliculosa or Saccharomyces fragilis it CAN be. That is na exceedingly small obstacle to overcome.

    There was a scandal back in the 80’s surrounding these native wonder plants. Some say that it was the seed sellers, other say it was the equipment sellers, but the most believable accussation centers around several midwestern State Attorney Generals who were in the pocket of (now, get this) Big Corn!

    For some reason, I tend to believe the latter….because it involves …ugh…”politicians”!

    The great spoilers of great ideas!

    That’s my story and I’m sticking to it.

    Oh, and…sawgrass is good, too!

  • LonnieB

    Ahhh! At last! A post about alternative palnts for the production of ethanol, or “celluline”, as Nick would have it.

    JERUSALEM ARTICHOKES!!!!

    It is a weed that grows all over central North America all by itself, and can be grown practically anywhere else, from the rich plains of Illinois to the poor soils of Wyoming. It can be grown on land most farmers would scoff at. Being native to this continent, it is immune to just about every bad bug and spore America has to offer.

    Properly (& extrememly easily) cultivated, it can produce as much as 15 tons of tubers per acre, yielding approximately 1,200 gallons of ethanol per acre (if my memory serves me, corn is around 400 g.p.a.).

    Even though it is a delicacy, especially in France (they eat anything), it is not a food commodity crop, so it doesn’t take porage away from the starving Ethernopians.

    In fact, it can be used as feedstock for cattle as well as ethanol distilation, both first and second generation processes.

    It contains carbohydrates called Inulins, and cannot be fermented using regular Brewer’s yeast. But suing other starins of yeast such as Kluyveromyces fragilis, Kluyveromyces marxianus, Torulopsis colliculosa or Saccharomyces fragilis it CAN be. That is na exceedingly small obstacle to overcome.

    There was a scandal back in the 80’s surrounding these native wonder plants. Some say that it was the seed sellers, other say it was the equipment sellers, but the most believable accussation centers around several midwestern State Attorney Generals who were in the pocket of (now, get this) Big Corn!

    For some reason, I tend to believe the latter….because it involves …ugh…”politicians”!

    The great spoilers of great ideas!

    That’s my story and I’m sticking to it.

    Oh, and…sawgrass is good, too!

Back to Top ↑