Researchers: Standard for life cycle analysis needed

Ethanol Producer Magazine
October 2008
By Susanne Retka Schill
Web exclusive posted Sept. 8, 2008 at 5:05 p.m. CST

Ethanol producers are well aware that some of the confusion in the debate surrounding ethanol and its performance in greenhouse gas (GHG) reduction and net energy yield is fueled by which numbers and study to use in making those claims.

Two Nebraska researchers call for a standardization of the life-cycle metrics in their paper, titled “Towards Standardization of Life-Cycle Metrics for Biofuels: Greenhouse Gas Emissions Mitigation and Net Energy Yield,” which is published in the current Journal of Biobased Materials and Bioenergy.

Adam Liska and Kenneth Cassman with the Nebraska Center for Energy Sciences Research take an in-depth look at the challenge of developing a life cycle analysis. One example from the paper demonstrates the complexity and importance of choosing the proper methodology. The authors explain that net energy can be expressed as a net energy ratio (NER) of the output divided by the energy input, or as a net energy value (NEV) of the output minus the input (generally expressed in megajoules per liter), or as the net energy yield (NEY) which is the output minus the input on a crop feedstock production area basis (usually expressed in gigajoules per hectare).
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