ETHANOL produced by Project Liberty, US biofuel company Poet's first planned commercial cellulosic ethanol plant, will reduce carbon emissions by 111 per cent over gasoline, an independent lifecycle analysis shows.
The analysis, compiled in the US by Air Improvement Resource, Inc. out of Novi, Mich., highlighted a number of characteristics of Poet’s process that led to this large emissions reduction.
Specifically, Project Liberty produced ethanol from agricultural waste.
Because it uses a waste product from an existing crop, there were no additional inputs for planting and growing the feedstock.
Although often disputed, the theory of indirect land use change has not impacted on the cellulosic ethanol.
In addition, the waste stream from Poet’s process was fed into two anaerobic digesters to create biogas.
Enough biogas is produced to completely power both Project Liberty and the adjacent grain-based ethanol plant.
The natural gas that is displaced in this process is credited to the cellulosic ethanol plant.
“The production of biogas as a co-product is an exciting aspect of this process,” POET chief executive Jeff Broin said.
“We will use renewable energy to produce renewable energy.”
The analysis found all the inputs into Project Liberty would emit 41.8 grams of carbon dioxide equivalent units per megajoule of energy produced.
The biogas exported as a co-product will offset 49.8 gCO2eq/MJ.
EPA estimates for land use and agriculture changes offset an additional 1.7 gCO2eq/MJ, bringing Project Liberty's total emissions to -9.7 gCO2eq/MJ.
EPA’s standard for gasoline emissions is 92.9 gCO2eq/MJ.
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