Alternative Fuels

Impact of Weather on Ethanol Energy Value

Ethanol from corn and other crops is regarded as an important alternative to fossil fuel while it is also considered to have a positive impact on the environment through a reduction in carbon dioxide emissions. However, many questions have been raised about the actual net energy value (NEV), i.e., the output energy in the ethanol and co-products minus input energy requirements in the production chain of ethanol produced from corn. UGA agricultural and biological engineers wanted to determine the impact of irrigation and nitrogen fertilizer practices, planting date, and the temporal and spatial variation in weather and climate on the NEV of ethanol produced from corn grain in the Georgia and other southeastern states. The study is performed by predicting corn yield with a computer model using a range of crop management scenarios and local weather and soil conditions as input. Initial results show that the NEV of ethanol from corn grain produced under southeastern U.S. conditions was less than 25 percent of the energy input needed, or negative, depending on farm management practices and climate conditions. Irrigation had a positive impact on the ethanol NEV as a result of an increase in yield. High nitrogen application rates had a negative impact on ethanol NEV for rainfed conditions. For irrigated conditions, planting in late March resulted in higher ethanol NEV than planting in early March. (2007)

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