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Thread: Leaves as bio-fuel

  1. #1
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    Leaves as bio-fuel

    We've had a great crop of leaves falling into our yard this fall. While raking them, I wondered if they would serve as a bio-fuel that wouldn't take up crop land used for food or feed production. I checked it out on my computer and found that a number of people have talked about it. I'm wondering if it has ever been attempted on acommercial scale?

  2. #2
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    I suppose there have been numerous small scale attempts. I can burn ten percent tree leaves in my wood stove, but I get little heat at 20% and lots of smoke unless the leaves are uniformly mixed with the other fuel. If the leaves are cut into one centimeter squares or smaller they burn better. Less moisture content than newly fallen leaves also helps. Partially composted helps little or none, Glazed paper bits are much like leaves = poor fuel. Unglazed paper torn into narrow strips burns good, but wider strips block the air flow to the fire. I suspect blocking air flow is the major reason leaves burn poorly.
    I've also heard that more than 10% tree leaves slows the action of composting.
    Algae can likely covert tree leaves to oil or alcohol, but my guess is too slow to be competitive with fossil fuel. Time is money in most endeavors. Neil

  3. #3
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    why would you want to burn up all that free lawn fertilizer?
    just chop it up with the lawn mower and let nature do it's thing to make your grass grow green and luxurious next year.
    besides, it's not like leaves are available year round, so it wouldn't be a steady source of fuel.

  4. #4
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    I was thinking about subsituting leaves for the corn in the production of alcohol. Corn isnt available the year around unless it is stored. Maybe leaves could be stored so as to provide continuous alcohol production. Most urban leaves end up in land fills.

  5. #5
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    Cellulosic ethanol

    http://en.wikipedia.org/wiki/Cellulosic_ethanol provides information on cellulosic ethanol. Can this come from deciduous leaves too?

    Cellulosic ethanol is a biofuel produced from wood, grasses, or the non-edible parts of plants.

    It is a type of biofuel produced from lignocellulose, a structural material that comprises much of the mass of plants. Lignocellulose is composed mainly of cellulose, hemicellulose and lignin. Corn stover, switchgrass, miscanthus, woodchips and the byproducts of lawn and tree maintenance are some of the more popular cellulosic materials for ethanol production. Production of ethanol from lignocellulose has the advantage of abundant and diverse raw material compared to sources like corn and cane sugars, but requires a greater amount of processing to make the sugar monomers available to the microorganisms that are typically used to produce ethanol by fermentation.

    Switchgrass and Miscanthus are the major biomass materials being studied today, due to their high productivity per acre. Cellulose, however, is contained in nearly every natural, free-growing plant, tree, and bush, in meadows, forests, and fields all over the world without agricultural effort or cost needed to make it grow.

    According to U.S. Department of Energy studies[1] conducted by Argonne National Laboratory of the University of Chicago, one of the benefits of cellulosic ethanol is that it reduces greenhouse gas emissions (GHG) by 85% over reformulated gasoline. By contrast, starch ethanol (e.g., from corn), which most frequently uses natural gas to provide energy for the process, may not reduce GHG emissions at all depending on how the starch-based feedstock is produced.[2] A study by Nobel Prize winner Paul Crutzen found ethanol produced from corn, and sugarcane had a "net climate warming" effect when compared to oil.[3]

  6. #6
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    Quote Originally Posted by JESMKS View Post
    I was thinking about subsituting leaves for the corn in the production of alcohol. Corn isnt available the year around unless it is stored. Maybe leaves could be stored so as to provide continuous alcohol production. Most urban leaves end up in land fills.
    Not a lot of sugar in most leaves, it is the plant sugars that are converted to alcohols in the fermentation process. With leaves, you're looking at cellulose conversion, which is possible, just not real efficient with most of the current processes, of course, if you're not real concerned about a highly efficient process there are lots of biological processes but they are a lot more complicated than making mountain dew:

    http://www.journeytoforever.org/biof...rth/meCh5.html

    http://www.oregon.gov/ENERGY/RENEW/B...CES/OCES_B.PDF

    http://www.archive.org/stream/biolog...trich_djvu.txt

    http://www.wilsoncenter.org/news/doc...0cellulose.pdf

    All of the above contain essentially the same information with a few little differences in explanation and details, but they are interesting introductory references for those who are interested in this type of process.

  7. #7
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    Poor choice for biofuel!

    As novaderrik says, fertilizer!

  8. #8
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    Oils, such as soybean oil, are much better biofuels than any alcohol.
    I'm a cynical optimist. I think the only way out is through, but once we get through it'll be better. Very different, but better. Howard Tayler

    It is not the most intellectual of the species that survives; it is not the strongest that survives; but the species that survives is the one that is able best to adapt and adjust. Charles Darwin

    Power, Lord Acton says, corrupts. Not always. What power always does is reveal. Robert A. Caro

  9. #9
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    Leaves much better for your garden if you put them into their own compost heap, and let the worms deal with them for a year or two. As Tracar says above, autumn leaves have been stripped by the tree of all nutrients. What is left is almost pure cellulose.
    What you dig out of a two year old leaf pile will be a large mass of bacteria and worm droppings, much more nitrogen than you put in, with some cellulose broken down and the rest broken up into small particles. Food for plants, food for invertebrates, and in fact 'food' for the soil that needs organic particles to maintin its structure.
    JOhn

  10. #10
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    Most city people don't have gardens or compost heap, but they do have lots of leaves from trees. If a Pennsylvania Company using wood chips and employing a plasma gasifier and a "proprietary" owned bacteria to convert synthesis gas into ethanol and make a profit; maybe the same process could successfully utilize other wood products such as leaves.

  11. #11
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    Quote Originally Posted by JESMKS View Post
    Most city people don't have gardens or compost heap, but they do have lots of leaves from trees. If a Pennsylvania Company using wood chips and employing a plasma gasifier and a "proprietary" owned bacteria to convert synthesis gas into ethanol and make a profit; maybe the same process could successfully utilize other wood products such as leaves.
    or people could just chop up the leaves and leave them spread out over the lawn to help it grow green an lush next spring without using any store bought fertilizer products.
    seems to be the "greenest" thing to do with the leaves.

  12. #12
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    How do you keep them from blowing away?

  13. #13
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    I run a mulching lawn mower over them, and the little tiny pieces don't blow away.

    However, I can imagine that people who have lots and lots of deciduous trees would need to rake up some of the leaves as they might smother the lawn even after they were mulched.

    Even someone with a fairly small yard could probably make a bin to hold shredded leaves -- in a hidden corner of the yard, ideally.

    I wish I had more leaves, I have to put other stuff in my compost bin.

  14. #14
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    My small yard has way too many tall trees, and thus too many leaves, mixed with small sticks. In some spots the mulched leaves have killed not only the grass but the weeds even though we rake about 80% of the leaves for the city to take away. This is further aggravated by the lawn not getting enough sun due to too many shade trees. Here in Jacksonville, Florida about half of the trees do not shed their leaves in the fall, but drop a few leaves every month of the year, so we do have a continuing supply. Two years seems like forever to make compost now that I am age 77. I've heard much faster composting is possible, but the minimum size is about a one meter cube. Worse the pile needs air and the correct amount of water, and other stuff besides leaves, of which we have very little. A slow compost pile can stink, and attract rats, flies and roaches if you put garbage and dog poop in it. Neil

  15. #15
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    I have a series of three compost bins, but then I live in the country. I put yard waste as well as vegetable scraps in mine, and no problems with critters to speak of. And i do have lots of critters in the woods nearby.

    I go out and poke holes in a bin once in awhile to let in air, and every few months turn it when I get around to it. If I was more active in turning it, I would get a finished product in a month or two. But I'm too lazy so I generally get a new batch done every summer.

    If it stinks, then it is either too wet or has too much nitrogen, causing anerobic activity.

    I remember watching a gardening show on TV, and they were interviewing the owner of a recycling center. It went something like this:

    "So they pay you to haul away their yard waste?"
    "Yes."
    "And then they pay you for compost you make from it?"
    "Yes." (pause) "Is this a great country or what?"

  16. #16
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    If sometime in the future, leaves become important in the production of ethanol, the Horse Chestnut tree will be high on the list of trees listed by leaf production per tree.

  17. #17
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    If you want that compost pile to work well, give it a can of beer. Really.
    Cheap beer is a good compost starter.

  18. #18
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    Quote Originally Posted by danscope View Post
    If you want that compost pile to work well, give it a can of beer. Really.
    Cheap beer is a good compost starter.

    I'll try that.

    Next time I have a can of cheap beer. Or leftover beer.

    Might be a few years before one of those conditions is met.

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