The impact of ethanol and ETBE blending on refinery operations and GHG-emissions

The sustainability of biofuels, including the greenhouse gas (GHG) reduction that they achieve, is getting increased attention. Life cycle analyses (LCAs) of biofuels production routes show that the GHG savings may vary significantly for different biofuels. An increasing number of governments are therefore looking for options to differentiate between biofuels according to their actual GHG savings. Accurate calculations of GHG savings thus become increasingly important. This paper deals with an omission of current LCAs for ethanol and ETBE blends, which leads to an underestimation of their calculated GHG savings. Current studies do not take into account that refiners will adjust their refinery operation when bioethanol or ETBE is added, because of the different characteristics of these products. The analysis indicates that the net effect of these refinery modifications on the GHG savings is positive, i.e. GHG-emissions reduce in both cases. The emission reduction is highest in the case of ETBE. We recommend to include this effect in future LCA calculations for ethanol and ETBE. As the calculation model used for this study is only a simplified representation of the EU refinery sector, we also advise to perform a more detailed analysis of these effects using more elaborate refinery models. (C) 2009 Elsevier Ltd. All rights reserved.