Biofuels not as "green" as many think

Discussion in 'Earth Science' started by Plazma Inferno!, Aug 29, 2016.

  1. Plazma Inferno! Ding Ding Ding Ding Administrator

    Statements about biofuels being carbon neutral should be taken with a grain of salt. This is according to a study of researchers at the University of Michigan Energy Institute after completing a retrospective, national-scale evaluation of the environmental effect of substituting petroleum fuels with biofuels in the US. America’s biofuel use to date has in fact led to a net increase in carbon dioxide emissions.
    The use of liquid biofuels in the transport sector has expanded over the past decade in response to policies such as the US Renewable Fuel Standard (RFS) and California’s Low-Carbon Fuel Standard (LCFS). These policies are based on the belief that biofuels are inherently carbon neutral, meaning that only production-related greenhouse gas emissions need to be tallied when comparing them to fossil fuels.
    This assumption is embedded in the lifecycle analysis modelling approach used to justify and administer such policies. Simply put, because plants absorb carbon dioxide as they grow, crops grown for biofuels should absorb the carbon dioxide that comes from burning the fuels they produce. Using this approach, it is often found that crop-based biofuels such as corn ethanol and biodiesel offer at least modest net greenhouse gas reductions relative to petroleum fuels.
    Using the Annual Basis Carbon (ABC) method, team of reserachers found that the gains in carbon dioxide uptake by feedstock, such as corn, were enough to offset biofuel-related biogenic emissions by only 37 percent, rather than 100 percent, during the period 2005 to 2013.
    In this regard, the researchers concluded that rising US biofuel use has led to a net increase rather than a net decrease in CO2 emissions. This finding contrasts with those of lifecycle analysis models which indicate that crop-based biofuels such as corn ethanol and soy biodiesel lead to a modest reduction in greenhouse gas emissions.

    ajanta and sculptor like this.
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  3. sculptor Valued Senior Member

    Add in the long term cost of draining the ogallala aquifer to plant all that extra corn.
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  5. exchemist Valued Senior Member

    ......And sadly, we will not now have Billy T wading in, to put the counterargument in favour of biofuels.

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  7. billvon Valued Senior Member

    Yes, that's sad; he sometimes had a one track mind but his heart was in the right place.

    Let me carry on in my own way here - yes, there are biofuels that are better than others. Perhaps the most important factor is EROEI, or energy in vs energy out. Some biofuels (most biodiesel, some kinds of ethanol) have a fairly high EROEI. Corn ethanol, as the OP points out, is considerably lower.
  8. iceaura Valued Senior Member

    Billy pushed sugar cane ethanol from tropical plantings, which is much different from maize ethanol via temperate zone industrial agriculture.

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