November 03, 2009

Ethanol has up to 2.2 to 1 Energy Return and Half of the Green House Gases of Gasoline

New Energy And Fuel reports on a new study which says that previous studies that tarred ethanol as an environmental villain were flawed because they looked at outdated corn and ethanol production techniques. The more modern ethanol plants – which account for about 60% of U.S. production and will account for 75% by the end of 2009 – have become a lot more efficient at growing and harvesting corn and turning it into alternative fuel.

(H/T Al fin)

(17 page pdf, for the new study) Improvements in Life Cycle Energy Efficiency and Greenhouse Gas Emissions of Corn-Ethanol

Directeffect GHG emissions were estimated to be equivalent to a 48% to 59% reduction compared to gasoline, a twofold to threefold greater reduction than reported in previous studies. Ethanol-to-petroleum output/input ratios ranged from 10:1 to 13:1 but could be increased to 19:1 if farmers adopted high-yield progressive crop and soil management practices. An advanced closed-loop biorefinery with anaerobic digestion reduced GHG emissions by 67% and increased the net energy ratio to 2.2, from 1.5 to 1.8 for the most common systems. Such improved technologies have the potential to move corn-ethanol closer to the hypothetical performance of cellulosic biofuels. Likewise, the larger GHG reductions estimated in this study allow a greater buffer for inclusion of indirect-effect land-use change emissions while still meeting regulatory GHG reduction targets. These results suggest that corn-ethanol systems have substantially greater potential to mitigate GHG emissions and reduce dependence on imported petroleum for transportation fuels than reported previously.


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