Some have challenged the net energy balance of biofuels. Is there an energy gain in the production of ethanol or biodiesel?
Ethanol derived from corn delivered at the pump yields 1.0 unit of energy for 0.74 units of fossil energy. By contrast, energy used to process petroleum takes 1.23 units to deliver 1 unit of gasoline at the pump. Delivering one unit of cellulosic ethanol energy at the pump takes only 0.10 units of fossil energy (Michael Wang, An Update of Energy and Greenhouse Gas Impacts of Fuel Ethanol, Argonne National Laboratory, Feb. 2005). Ethanol has been criticized over the years for its net energy balance. Two recent independent high profile metastudies in the leading journals Science (Alexander E. Farrell, et al. “Ethanol Can Contribute to Energy and Environmental Goals,” Vol. 311, 27 January 2006, pgs 506-508) and Environmental Science and Technology (Roel Hammerschlag, “Ethanol’s Energy Return on Investment: A survey of the Literature 1990-Present,” February 2006) revealed that ethanol critics used some obsolete data and inadequate methods in their analyses. Cellulosic ethanol has a signifi