Assessing the greenhouse gas emissions from poultry fat biodiesel

This article attempts to answer the question: What will most likely happen in terms of emitted greenhouse gases if the use of poultry fat for making biodiesel used in transportation is increased? Through a well-to-wheel assessment, several different possible scenarios are assessed, showing that under average conditions, the use of poultry fat biodiesel instead of diesel leads to a slight reduction (6%) in greenhouse gas emissions. The analysis shows that poultry fat is already used for different purposes and using poultry fat for biodiesel will therefore remove the poultry fat from its original use. This implies that even though the use of biodiesel is assumed to displace petrochemical diesel, the 'original user' of the poultry fat will have to find a substitute, whose production leads to a greenhouse gas emissions comparable to what is saved through driving on poultry fat biodiesel rather than petrochemical diesel. Given that it is the production of the substitute for the poultry fat which mainly eliminates the benefit from using poultry fat for biodiesel, it is argued that whenever assessing the greenhouse gas emissions from biodiesel made from by-products (such as rendered animal fats, used cooking oil, etc.) it is very important to include the oil's alternative use in the assessment. (C) 2011 Elsevier Ltd. All rights reserved.