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Switchgrass is nothing less than amazing!

BBC News reports on a new study, Grass biofuels 'cut CO2 by 94%'.

Producing biofuels from a fast-growing grass delivers vast savings of carbon dioxide emissions compared with petrol, a large-scale study has suggested.

A team of US researchers also found that switchgrass-derived ethanol produced 540% more energy than was required to manufacture the fuel.

One acre (0.4 hectares) of the grassland could, on average, deliver 320 gallons of bioethanol, they added.

This is good news for the United States in so many ways:

  1. Fewer CO2 emissions - 94% is almost "carbon neutral"

  2. 540% EROEI - Growing "energy independence"

  3. Better than corn and soy - Less need for harmful herbicides and pesticides, such as Atrazine

  4. Native prairie grass - Improves local biodiversity

  5. Plant once - Reduces erosion and farm fuel consumption

The five-year study on switchgrass (Panicum virgatum) was led by Ken Vogel, a professor at the University of Nebraska-Lincoln and a geneticist for the U.S. Department of Agriculture. His findings are published this week by in the Proceedings of the National Academy of Sciences USA, Net energy of cellulosic ethanol from switchgrass (PDF) (Abstract).

According to Nature News, Prairie grass energy boost studied in the field. There is more energy potential in switchgrass than in other crops used in biofuels. Vogel estimated that annually a hectacre of switchgrass could produce an average of 60 gigajoules of energy if turned into bioethanol. Switchgrass had a net 540% Energy Returned on Energy Invested (EROEI). "Soya bean biodiesel, in contrast, returns 93% more energy than is used to produce it, whereas corn grain ethanol currently provides only 25% more energy. Greenhouse-gas emissions from the switchgrass would be 94% lower than emissions from petrol, they calculate — that's nearly, but not quite, carbon neutral."

The Reuters story on the study explains how the CO2 savings is made.

Switchgrass plants sequester carbon dioxide in the ground because they have extensive root systems that remain buried after the crop is harvested, Vogel said. Steep greenhouse gas emissions reductions, of about 94 percent compared to gasoline, are contingent on burning switchgrass waste to fire bio-refineries. Unlike waste left over from corn after it is made into ethanol, switchgrass waste cannot be made into the animal feed distillers' grain.


Corn and soybeans need to be planted every year. This causes increased risk of soil erosion and the non-native crops require using herbicides and pesticides that can be environmentally harmful to wildlife and people. Scientific America reports Grass makes better ethanol than corn does. Switchgrass only needs to be planted once and is a plant indigenous plant to the vast American prairie and "once established, the fields yielded from 5.2 to 11.1 metric tons of grass bales per hectare, depending on rainfall". But, there still is a large challenge blocking the adoption of switchgrass ethanol.

But yields from a grass that only needs to be planted once would deliver an average of 13.1 megajoules of energy as ethanol for every megajoule of petroleum consumed—in the form of nitrogen fertilizers or diesel for tractors—growing them. "It's a prediction because right now there are no biorefineries built that handle cellulosic material" like that which switchgrass provides, Vogel notes. "We're pretty confident the ethanol yield is pretty close." This means that switchgrass ethanol delivers 540 percent of the energy used to produce it, compared with just roughly 25 percent more energy returned by corn-based ethanol according to the most optimistic studies.

As noted, the catch is there presently are not any biorefineries that handle the switchgrass. The refineries are currently geared toward producing ethanol from corn and soybeans. However this may be about to change. In a story about the study, Associated Press reports on the effort underway to develop cellulosic ethanol:

Renewable Fuels Association spokesman Matt Hartwig said this latest study adds to the evidence supporting the development of cellulosic ethanol.

"It underscores that cellulosic ethanol production is not only feasible, it is essential," said Hartwig, whose group represents ethanol producers.

Nebraska Ethanol Board Projects Manager Steve Sorum said the industry is excited about the prospects for cellulosic ethanol because the feedstocks for it, such as switch grass, are cheaper to grow. Plus some of the byproducts created in the process can be burned to generate electricity.

Sorum said the key will be developing an economic way to break down the cell walls of cellulose-based fuel sources...

Last year, the Department of Energy announced plans to invest $385 million in six ethanol refineries across the country to jump-start ethanol production from cellulose-based sources, a process that has not yet been proven commercially viable.

When $385 million for cellulose ethanol production is compared to the opportunity costs due to the Bush administration's war in Iraq, our country's "jump start" is laughable. Kansas and Nebraska has spent $7.2 billion on the war and the entire country together has spent over $484.2 billion on it. To me, the nation's priorities are obviously wrong.

Changing to switchgrass-based ethanol would have additional environmental benefits. Growing native prairie grasses can help preserve our country's biodiversity and help reduce erosion and the use of pesticides and herbacides. According to Land of Biofuels? an article in this month's Minnesota Conservation, a journal published by the Minnesota Department of Natural Resources:

From tilling to fertilizing to irrigating to distilling, corn ethanol production consumes large amounts of fossil fuels and water -- offsetting some of the biofuel benefits of being local, renewable, and carbon neutral. And the increased demand for corn puts pressure on farmers to convert grasslands to cornfields. Soil erosion and water pollution increase when grassland is plowed and fertilized for corn. And few animals find cornfields to be as satisfactory for habitat as native grasslands and brushlands...

First, many plants -- particularly native perennial plants -- need far less fossil fuel input to grow, so production of ethanol from native plants would generate less CO2. Prairie grasses, such as switchgrass, big bluestem, prairie cordgrass, and Indiangrass (or better yet, a mixture including wildflowers), also provide superb wildlife habitat. Grasses help soil stay in place and filter polluted runoff. If plant species and genetic makeup, land, and harvest regimen were coordinated to maximize natural resource potential, native vegetation managed for cellulosic biofuels could provide far better homes for ducks, deer, songbirds, prairie chickens, and other native species than row crops.

"We think [biomass harvest] can have a positive benefit, particularly if it means something that's in row crop production now is converted to grass, or if it means we have lands that are decadent that we can then use biomass harvest as a management tool to increase the productivity of those lands for wildlife," says DNR farmland wildlife program leader Bill Penning. For instance, Penning says, DNR currently invests hundreds of thousands of dollars each year in brushland management for brushland-dependent wildlife species such as sharp-tailed grouse. If brush becomes a commodity, management could start to pay for itself.

"That's a win-win situation for us," Penning says. "We couldn't ask for anything more."

Neither could I. Switchgrass is amazing. Let's solve the challenges with cellulosic ethanol, start planting prairie grasses, and get those bio-refineries built. I cannot wait for this future for America and the heartland!

Originally posted to Magnifico on Wed Jan 09, 2008 at 01:48 PM PST.

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Comment Preferences

  •  Here's to wide open country! (32+ / 0-)

    Oh, give me land, lots of land under starry skies above,
    Don't fence me in.
    Let me ride through the wide open country that I love,
    Don't fence me in.
    Let me be by myself in the evenin' breeze,
    And listen to the murmur of the cottonwood trees,
    Send me off forever but I ask you please,
    Don't fence me in.

    •  Recommend some caution ... (9+ / 0-)

      we look to be awhile from large-scale cellulosic ethanol.

      And, this is unlikely to be a silver bullet.

      The EROEI is potentially greatly improved over other ethanol, with improved CO2 implications, but we have (again) awhile to get there.

      BY the way, the EROEI in fossil terms can be improved by using renewable power (wind) for processing the crop into fuel.

      •  No "silver bullets" (5+ / 0-)
        Recommended by:
        SarahLee, Janus, A Siegel, dotcommodity, oxon

        Indeed, the cellulosic ethanol refineries are the catch, a big one. You always have great ideas — using renewable wind power for biofuel crop processing is just another one of them.

        Even with the problems, a switchgrass powered future looks to me a lot better than a corn or soy powered future.

        •  Absolutely better ... (5+ / 0-)

          My concern, here, is the high pressure for massive biofuels.

          Much better, IMHO, to be driving toward electrification of transportation as much as possible, and then a less aggressive biofuels program could actually take a larger percentage of that far smaller remaining liquid fuel requirement.

          And, in terms of "biofuels", algae is something that is too underemphasized, imho, compared to corn, soy, switchgress/cellulosic ethanol.

          In any event, the biofuel craze is, imho, not looking at the systems of systems challenges with water, pollution (into the Gulf of Mexico), food prices, etc ... and switchgrass ameliorates, but does not solve, these problem areas.

          By the way, re cellulosic ethanol, my 'dream' concept is that it would be developed to be able to handle (industrial) hemp and bamboo, both of which are plants that grow like weeds, grow well with no fertilizer imputs, and could be grown as border plants in suburban yards around the country. Imagine high school science classes responsible for running the cellulosic ethanol plant that is using material cut from the yards in the local community.  

        •  A very big catch (2+ / 0-)
          Recommended by:
          Magnifico, oxon

          But most of the experts I've talked to don't think it's insurmountable. Government has a role to play, and it starts with Mark Udall's renewable electricity standard. Nothing spurs innovation like a good old-fashioned deadline.

        •  we need strict standards for biofuels (7+ / 0-)

          My colleagues prepared a report about ethanol and water resources. It's a good overview of some of the issues we need to consider when expanding biofuels production.

          Lisa Moore, Ph.D., Environmental Defense

          by ClimateLurker on Wed Jan 09, 2008 at 02:43:26 PM PST

          [ Parent ]

      •  Does anyone know whether calculations (1+ / 0-)
        Recommended by:

        have been made on how well switchgrass will grow when temperatures have risen a couple of degrees more? My understanding is that the IPCC regional prediction for the interior of the continental US foresees higher than average temperature increases and reduced rainfall. I know switchgrass is supposed to be drought resistant, but was just wondering if anyone is thinking about this.

        When we make calculations that depend on growing things we have to remember that our ability to grow crops in traditional areas is likely to be severely altered or curtailed by climate change.

        "My True Religion Is Kindness" -- The Dalai Lama

        by JohnnyRook on Wed Jan 09, 2008 at 03:28:30 PM PST

        [ Parent ]

        •  Where switchgrass grows best will shift ... (1+ / 0-)
          Recommended by:

          ... but switchgrass is not going to get squeezed out. A water-intensive, fertilizer-intensive crop like monocrop corn is going to have its range squeezed by increasing drought frequency over a wider area ... but a perennial like switchgrass will gain range on one margin as it loses range on the other.

          And, indeed, cellulosic ethanol is not sensitive to feedstock ... it could be coppiced wood in areas where forest is the natural climax state and elephant grass in areas that climax to tallgrass rather than shortgrass prairie.

 and Energize America

          by BruceMcF on Thu Jan 10, 2008 at 06:38:30 PM PST

          [ Parent ]

      •  A Siegel (1+ / 0-)
        Recommended by:
        A Siegel


        happy new year too!

        "Well we don't rent pigs and I figure it's better to say it right out front because a man that does like to rent pigs is... he's hard to stop" Gus McCrae

        by pfiore8 on Wed Jan 09, 2008 at 03:37:27 PM PST

        [ Parent ]

  •  Conservation of energy (3+ / 0-)
    Recommended by:
    greenskeeper, Rex Manning, nleseul

    means that 540% more energy than inputs is impossible. I don't know about you but i believe in the laws of thermodynamics.

    My guess is that the Clinton campaign will come up with a plan to deal with spontaneity. -Charlie Cook

    by waitingforvizzini on Wed Jan 09, 2008 at 01:52:21 PM PST

    •  I am guessing (9+ / 0-)

      that the input is the fuel energy used to till and harvest the switchgrass, and the output (ethanol derived from cellulose), as compared to the fuel energy used to till, fertilize, water and harvest corn or soy and the output (ethanol derived from sugar).

      In both cases, sunlight is an energy input when plants convert that energy through photosynthesis, but it is not a fuel input that a farmer directly contributes.

      Less fuel is needed on an annual basis once the switchgrass is planted, as switchgrass is a perennial rather than an annual, like corn or soy.

      January 20. 2009 cannot come soon enough.

      by Crisis Corps Volunteer on Wed Jan 09, 2008 at 01:59:14 PM PST

      [ Parent ]

    •  I think what he means (5+ / 0-)

      is that for every liter of petroleum you consume in processing switchgrass into fuel, you produce 54 liters of switchgrass-derived fuel.

      I don't think the diarist was intending to count sunlight or environmental heat in that accounting.

      Oh, my friend, how have we come / to trade the fiddle for the drum?

      by Shaviv on Wed Jan 09, 2008 at 02:00:23 PM PST

      [ Parent ]

    •  He's Not Counting the Solar (6+ / 0-)

      ...and biodynamic inputs.

      Some people still think that neo-classical economics can trump thermodynamics, so they simply don't value any input that can be accessed without paying cash on the barrelhead.

      This is the big lie at the root of the Chicago School, and it's no better when it's reinforced for ostensibly "progressive" ends.

      •  wow (4+ / 0-)

        Some people still think that neo-classical economics can trump thermodynamics, so they simply don't value any input that can be accessed without paying cash on the barrelhead.

        if i'd written that sentence, i'd be terribly pleased with myself.

        Time for Miles to soothe me again, because jazz is the antibush. --zic

        by homo neurotic on Wed Jan 09, 2008 at 02:02:50 PM PST

        [ Parent ]

      •  Nobody Counts the Solar (5+ / 0-)

        I did a back of the envelope calculation a decade or more ago.  According to the annual energy budget then, agriculture accounted for 3% of all energy used.  I estimated that the solar input to grow the crops themselves was on the order of at least 100x of that figure.  Later, I had the chance to confirm that estimate with David Pimentel of Cornell, a great (and controversial) agronomist.  So if we are still using about 3% of the energy we count for agriculture, about 3 quadrilion btu's, then the solar input for agriculture is 300 quads, 3 times the annual energy budget of 100 quads.

        Now, let's start adding all the sunlight on south-facing windows.....

        We've always been a solar-powered society.  We will always be a solar-powered society.  Without sunlight we simply cannot exist.  Too bad nobody in the public sphere will admit that obvious truth and act on it.

        Solar is civil defense. Video of my small scale solar experiments at

        by gmoke on Wed Jan 09, 2008 at 02:07:18 PM PST

        [ Parent ]

      •  well, if it's free (2+ / 0-)
        Recommended by:
        waitingforvizzini, Magnifico

        Then the value is $0, though maybe "priceless" would be more apt in this case.

        Quick! Man the Blogs!

        by HiBob on Wed Jan 09, 2008 at 02:09:11 PM PST

        [ Parent ]

      •  Could you explain what you mean? (0+ / 0-)

        I honestly don't understand, and would like to.

        Just trying to get a better grasp of the evolving knowledge on all of these new technologies and myriad developments; corn ethanol seemed like a great idea and now we know it's not. I'm late to the game and trying to catch up.

        Thanks in advance for any (simple English for non-science majors) to understand.

        •  I'm Talking About Green Capital (1+ / 0-)
          Recommended by:

          I'm talking about the value of the services provided by natural systems.

          I'm also suggesting that while we think that "capturing unused solar energy" is free, we need to be very careful.

          Natural systems operate inside tolerances that are often narrower than we imagine and all of that "uncaptured energy" is currently contributing in ways we can't currently understand.

          Ultimately, we need to accept that the total amount of energy available for annual human use is a small percentage of the total annual solar gain on the planet's surface.

          Every other form of energy use is what a banker would call "dipping into the principal rather than living on the interest."

      •  EROEI (2+ / 0-)
        Recommended by:
        waitingforvizzini, Magnifico

        Energy Return On Energy Invested.

        That's what the diarist is trying to get at.

        Positive EROEI = nature supplies the difference, humans must spend less energy to access it.  Solar, wind, uranium, and of course fossil fuels until they peak and decline.

    •  the surplus enjoyed is deferred solar (4+ / 0-)
      Recommended by:
      waitingforvizzini, cfk, Magnifico, Shaviv

      the plant is basically a savings account for the solar inputs.the necessary anthropogenic energy inputs needed to access them are less than the total available energy derived from the plant once you get to make that withdrawl.

      Time for Miles to soothe me again, because jazz is the antibush. --zic

      by homo neurotic on Wed Jan 09, 2008 at 02:00:46 PM PST

      [ Parent ]

    •  Dh! (2+ / 0-)
      Recommended by:
      waitingforvizzini, Magnifico

      They only count the energy human producers put into the system, they don't count the energy captured from the sun in making their calculations.

      eschew obfuscation

      by jimG on Wed Jan 09, 2008 at 02:03:45 PM PST

      [ Parent ]

    •  No ... (4+ / 0-)

      what this is being discussed is the EROEI.

      Easy, cheap oil is something like 500-to-1.  1 barrel of oil (or equivalent) required to get out 500 new barrels.

      Now, that does not count the solar radiation, plant growth, and millions of years of cooking the mix as part of the equation.

      Corn ethanol has been rated at somewhere between .7 and 1.7 EROEI in terms of fossil fuel imputs. That, in best case with current practices, it returns less than twice the energy as that (other than sun) required to grow / process it.

      The new study suggests a potential for getting somewhere in the range of a 6-1 EROEI, that the processes might return six times the energy output (other than solar radiation, which is not part of the equation here) as the input required to be able to grow the crop and process it into fuel.

    •  Title changed (1+ / 0-)
      Recommended by:

      I modified the title to make it less magical.

    •  Net energy return on input ... (1+ / 0-)
      Recommended by:

      ... of course its not a perpetual motion machine.

      Its like the NEROI on the production of gasoline ... of course the final energy all came from the energy already contained in the crude oil ... the NEROI is about the energy input required in order to harvest the energy resource ... to turn the raw resource into a useable commodity.

      If it is 0% or less (that is, EROI of 100% or less), then clearly the process is not acquiring energy for the economic system but is just transporting energy that has already been acquired. And under some characteristics, corn ethanol NEROI can be under 0% ... the NEROI of +25 is based on ongoing improvements in corn production energy efficiency ... and, indeed, it could go backwards again if there were external shocks that undermined corn productivity. and Energize America

      by BruceMcF on Thu Jan 10, 2008 at 06:44:04 PM PST

      [ Parent ]

  •  Can't tell you how much I want this to work (8+ / 0-)

    God, I hope it does. And fast.

    Thank you for a fascinating diary.

    You can tell you have created God in your own image when it turns out that he or she hates all the same people you do. - Anne Lamott

    by javelina on Wed Jan 09, 2008 at 01:56:26 PM PST

  •  Put it in residential areas (5+ / 0-)

    like on my lawn.  Have the yard waste infrastructure collect it, like they do with leaves and sticks now.

    I would gladly grow prairie grass, I would even mow it and give it to the refineries for free.  If 10% of residences that have wasted tons of fertilizer and weed killer did that, you would have a huge suppy.  Even if it were only in back yard gardens.

    This world is broken, I want a new one.

    by jimraff on Wed Jan 09, 2008 at 02:00:19 PM PST

    •  IIRC, the kinds of grass you use for this (2+ / 0-)
      Recommended by:
      jimraff, Magnifico

      are not the kind of grass most people want on their lawn, because it's tougher than most shade grass. I think.

      Then again, I'm someone who's partially destroyed his lawn mower by pushing it over a patch of thick crabgrass, so maybe it'd fit right in, over here.

      Oh, my friend, how have we come / to trade the fiddle for the drum?

      by Shaviv on Wed Jan 09, 2008 at 02:06:32 PM PST

      [ Parent ]

      •  Yes, it is not the type of grass most (0+ / 0-)

        people are used to as a lawn.  I would gladly not have to mow my lawn for several months as a trade.  I would make my kids deal with 3-4 foot high grass as well.

        Plus the amount of lawn space is huge, and would provide ample amount of produce.

        It would take a lot of change in peoples minds to do it though.

        This world is broken, I want a new one.

        by jimraff on Wed Jan 09, 2008 at 02:29:45 PM PST

        [ Parent ]

    •  I like that a lot! nt (1+ / 0-)
      Recommended by:
  •  yo Magnifico... (5+ / 0-)

    I see what you're trying to get at with your diary title; but an error in the BBC report propagated to your title and made it appear that you're talking about what many of us know well as an "energy scam."

    What you're trying to get at is called EROEI:  Energy Return On Energy Invested: how much energy humans have to expend to turn a resource into a usable form of energy.  

    EROEI is high when an energy source is highly accessible, for example a stored fuel such as fossil fuels or uranium; or a highly productive wind site or solar site.  

    If it takes more oil to get a given quantity of oil out of a well and refine it into usable products, than the amount of energy that the quantity of oil can provide, then we say that the EROEI has gone negative, and the oil is no longer useful as an energy source (though it will still be useful as an industrial feedstock, at much higher prices).  

    What the BBC and you were trying to say about switchgrass is that it has a very high EROEI.  But the way BBC put it, it looked as if they were talking about violating the laws of thermodynamics.  In a thermodynamic sense, you can never get more energy out than you put in, otherwise perpetual motion machines would be possible.  People involved in the renewable energy scene know well the large number of crackpots and innocent but mis-informed or mistaken inventors who claim to have built miraculous energy devices that produce "over-unity" output: more energy out than in.  

    To complicate matters further, there are some reasonably respectable theories in physics that imply the existence of virtually unlimited energy if a means could be found to tap it (e.g. the "zero-point field").  And those theories become the starting point for a lot of the crackpottery and innocent mistakes.  

    So what I would do is change your title to something like "Switchgrass: a better source of ethanol" or some such.  Your present title is probably scaring away otherwise-interested readers who think you might be "promoting a crackpot scheme."   You might want to just re-run the diary tomorrow under a new title because it may have rolled off the screen today.

    Does this make sense?  

  •  i find this incredibly exciting (2+ / 0-)
    Recommended by:
    javelina, Magnifico

    and/but i suspect the exxon-mobil's and adm's alike will do what they can to thwart progress here.

    Time for Miles to soothe me again, because jazz is the antibush. --zic

    by homo neurotic on Wed Jan 09, 2008 at 02:08:33 PM PST

  •  A simple matter of money, priorities and water (2+ / 0-)
    Recommended by:
    sc kitty, 4Freedom

    A Manhattan Project like focus on renewable biological energy sources could produce commercially viable ethanol in a few years.

    We can do it if our government promotes it with sufficient funding.

    A tax on fossil fuels could easily provide the funding needed - but passing legislation will be difficult without control of the Congress and Presidency.

    That's why we need representatives and a President who are not beholden to entrenched interests like the petroleum producers.

  •  So what's the overall efficiency (0+ / 0-)

    compared with current solar power possibilities?

    Let's see, 320 gal/0.4 ha ~ 800 gal/ha ~ 3000 l/ha ~ 0.3 l/m2. Ethanol energy content is 21.1 megjoules/l, so we get 6.4 MJ/m2 from the crop, which is about 1.76 kwh/m2, before subtracting whatever power is needed for harvesting or conversion.

    According to Wiki, photovoltaic solar cells in the US (at 15% energy efficiency) deliver roughly 0.9 kwh/m2/day. Even assuming only 100 days of sunlight per year, that's 90 kwh/m2--roughly 20 times as much power as available from switchgrass C2H5OH.

    Put another way, this BOTE calculation suggests that the overall efficiency of solar energy conversion is something under 1%.

    (That's if the 320 gal/A number is for a whole season of switchgrass. If it's for a single harvest you'd have to multiply by the number of harvests per year. It's not clear in the BBC story which. Anyone have some insight here?)

    Now admittedly, it's more or less free energy--you're not gonna cover the prairies with solar cells, & the stuff grows on its own pretty much anywhere in the Midwest--& it seems to be a great first step, but it does look as if there's some room for improvement here.

    May I bow to Necessity not/ To her hirelings (W. S. Merwin)

    by Uncle Cosmo on Wed Jan 09, 2008 at 02:36:03 PM PST

    •  Looks like 2 cuttings per growing season (0+ / 0-)


      Now if we diddle the DNA to fix nitrogen & grow faster...

      (Yeah, I know, no Frankengrass allowed...)

      May I bow to Necessity not/ To her hirelings (W. S. Merwin)

      by Uncle Cosmo on Wed Jan 09, 2008 at 02:52:46 PM PST

      [ Parent ]

    •  Couple of issues (0+ / 0-)

      There remains a need for liquid fuels, though hopefully in nowhere near the quantities currently used (and I suspect ethanol will not be the preferred form). Battery energy density is nowhere near that of liquid fuels with no prospects in the foreseeable future to match them.

      Secondly, I keep seeing comparisons of PV to biomass. One produces electrical power, the other chemical energy. To convert the former to energy, the power generated is simply integrated over time. Of course in reality you need the infrastructure to store that energy. The energy cost associated with that is all too often left out. It also assumes that electrical energy and chemical energy are functionally equivalent. They're not.

      Personally, I see the need for widespread electrification of transport (second only to reduction of VMT), and my take on cellulosic is "Show me that it really works". But let's compare apples to apples here.

  •  nice to explore options - but a word of caution (2+ / 0-)
    Recommended by:
    Magnifico, Uncle Cosmo

    The paper does not account for nitrous oxide emissions.  

    Nitrous oxide (N2O) is a very powerful greenhouse gas -- ton for ton, it has a global warming potential 298 times higher than CO2.  Fertilized soils can emit large amounts of N2O, so any full cycle accounting of the climate impacts of a biofuel crop should include N2O.

    Still, as the study's authors say, it's a "baseline study". Hopefully a follow-up paper will present data (or at least estimates) of N2O emissions.

    Lisa Moore, Ph.D., Environmental Defense

    by ClimateLurker on Wed Jan 09, 2008 at 02:36:19 PM PST

    •  Not entirely clear (1+ / 0-)
      Recommended by:

      This is a frustrating paper, since there is no "Experimental methods" section or equivalent. But in the Supplemental Information they do note that the GHG CO2 equivalent emissions include that from nitrogen application. But they don't specify how they estimate that (or even if N2O is part of CO2eq, though I can't imagine that they'd omit it), or what conditions they use in the modeling. But the lack of measured data was disappointing.

  •  Well (1+ / 0-)
    Recommended by:

    The first thing we need to do is stop using corn ethanol, which is an environmental disaster.  If you look at the energy bill, there is a huge focus on increasing corn ethanol production with a little money thrown at cellulostic research.  Corn ethanol is being called a transitional fuel, but there are too many people making money off of corn ethanol that won't make money off of cellulostic ethanol.  

    John Edwards for President

    by Mia Dolan on Wed Jan 09, 2008 at 02:40:26 PM PST

  •  Wow! Great catch! (3+ / 0-)
    Recommended by:
    melo, Janus, Magnifico

    This makes me all tingly.

    The only question is how it would affect the cost of food, if land were to be diverted from food to fuel production.  It looks to me, though, that combining the two would help with moisture and soil retention, and could actually boost production of food crops in consequence.  At least in some instances.

    Let's go further.  One can see using derelict spaces to plant switchgrass, even on urban rooftops, given the ability to pull CO2 out of the atmosphere and lock it in the soil.  A Greenroof then becomes a carbon sequestering roof.  Might help a little.

    •  And a building that uses less energy to cool (1+ / 0-)
      Recommended by:

      Switchgrass and the soil you plant it in would reflect a lot more light than a black tar roof...

    •  See my comment upthread re efficiency (1+ / 0-)
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      Unless I'm off by a factor of 10 or more, you'd do better roofing with photovoltaic systems (or using the incident radiation for hot water or heating). Switchgrass ethanol looks interesting as a means of harvesting energy from the humongous acreage that's not doing anything constructive at the moment (e.g., highway or railbed rights-of-way).

      May I bow to Necessity not/ To her hirelings (W. S. Merwin)

      by Uncle Cosmo on Wed Jan 09, 2008 at 02:50:39 PM PST

      [ Parent ]

  •  Are you crazy? There are no (1+ / 0-)
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    subsidies on switchgrass. Won't work.
    Is this one of the "changes" that all the candidates talking hinting about? Be nice to hear somebody say "change our focus from food crops to switchgrass".

    The separation of art and science is impossible. Wendell Berry

    by emmasnacker on Wed Jan 09, 2008 at 02:48:20 PM PST

  •  btw, here's the study itself (1+ / 0-)
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    The summary and the PDF (one of those rare public access articles!)

    Lisa Moore, Ph.D., Environmental Defense

    by ClimateLurker on Wed Jan 09, 2008 at 02:56:49 PM PST

  •  Promising, with caveats (1+ / 0-)
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    From the PNAS paper:

    Caution should be made in making direct ethanol yield comparisons with cellulosic sources and corn grain, because corn grain conversion technology is mature, whereas cellulosic conversion efficiency technology is based on an estimated value

    Nobody knows what the actual EROEI of commercial cellulosic ethanol is, because no one has done it.

    GHG emissions are also estimated and not actually measured.

    Also, a caveat on the quote from the MDNR:

    If plant species and genetic makeup, land, and harvest regimen were coordinated to maximize natural resource potential, native vegetation managed for cellulosic biofuels could provide far better homes for ducks, deer, songbirds, prairie chickens, and other native species than row crops.

    The managed switchgrass fields in this study used herbicides as part of their energy inputs (though not much after planting). The management is important to this study, as the ethanol yields of managed fields were significantly higher than those of "low-input high-diversity" fields. No doubt the herbicides used don't affect ducks and deer much, certainly much less than row-crops would. But it's important to keep in mind that these fields are not toxin-free.

    Still and all, could be a useful silver BB. And while we're waiting, there's always conservation.

  •  Sounds promising (1+ / 0-)
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    I seem to remember reading somewhere that switchgrass grows in places where conventional food crops do not. If my memory is correct, this is significant, because the areas where switchgrass is grown would not take away from the ability to grow crops. My big qualm with using corn for fuel is that corn is a staple food in many people's diets. As fuel prices increase, the price of food then increases (as has happened in Mexico).

    May all your pickles be bright

    by Light Emitting Pickle on Wed Jan 09, 2008 at 03:24:04 PM PST

  •  Gratuitous comment in order to... (1+ / 0-)
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    regain my TU status. < /snark

    Seriously, great diary, Magnifico.

  •  sorta off topic (0+ / 0-)

    I ran into this link

    what do you think of it?

    myself I have no knowledge in this stuff. That why I read the diaries posted here on it.

    •  Questionable source? (0+ / 0-)

      If sun changes enough, it certainly will require revisions to our climate model. Ultimately, the sun will expand and then die... but that is going to be a while.

      The group that put out the press release purpose seems to be cloud the scientific consensus on climate change, but that's just a hunch on my part.

  •  I added the 'teaching' tag (0+ / 0-)

    and will include this diary in my weekly roundup "What have you got to learn?".  A link will appear in my sig when it goes up, about 9AM Eastern

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