Many studies have been conducted world-wide to examine the environmental impact of biofuels for transportation and estimate their cost and quantity potential. These studies have shown considerable differences in the findings and conclusions at times. In order to obtain an overview which identifies the strengths and weaknesses of the available studies and to determine further research needs, IFEU Institute Heidelberg conducted the present study.
This study analyses and compares all international, publicly accessible publications about all biofuels for transportation currently being used (e.g. biodiesel and bioethanol as well as those potential future biofuels like BTL). More than 800 studies were taken into account. From these, 63 studies satisfied the criteria for detailed analyses, leading to the evaluation of 109 balances of energy and greenhouse gases of various biofuels, which were compared either to conventional fuels or other biofuels. In most cases the complete life cycles of the fuels, from production to consumption, were considered.