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Biofuels versus Gasoline: The Emissions Gap Is Widening
(Environmental and Energy Study Institute) ... Many respected laboratories, agencies, and researchers have used a lifecycle analysis to show that biofuels, particularly advanced biofuels, provide significant carbon benefits compared to gasoline. These benefits have increased in recent years, as biofuels have become less energy-intensive to produce while oil/gasoline has become more energy-intensive to extract and produce.
The Department of Energy’s Argonne National Lab has developed the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) Model, the most comprehensive, up-to-date lifecycle assessment model for various fuels (including biofuels and petroleum-based fuels). A 2012 paper from researchers at Argonne shows that ethanol provides emissions reductions of between 19 and 48 percent compared to gasoline. This range can be attributed in part to different farming practices—more sustainable agricultural practices will lead to larger emissions reductions.
For example, according to Argonne’s GREET model, an energy crop like miscanthus can have negative GHG emissions, meaning that over the crop’s life cycle, carbon sequestration outweighs emissions. Argonne researchers show that compared to gasoline, biofuel from energy crops can reduce emissions by 101 to 115 percent. Corn stover, a residue from corn, can reduce emissions by 90 to 103 percent.
The oft-cited increase in GHGs from biofuels is based on EPA’s Regulatory Impact Analysis for the RFS from 2010. Since 2010, better data, continual improvements in lifecycle analysis modeling, and a richer understanding of the role of co-products produced in conjunction with biofuels have significantly reduced emission estimates for corn-based biofuels, and this updated data is reflected in the GREET model. The GREET model has demonstrated that the carbon intensity for ethanol has been steadily falling in the past decade.
On the other hand, more and more energy-intensive practices are being used to extract oil and produce gasoline. Oil from tar sands, for example, produces significantly more greenhouse gases than traditional petroleum, and is becoming a larger percentage of the fuel supply. Therefore, as biofuels replace more carbon-intensive gasoline, they provide even greater emissions reductions. READ MORE