Assessment on net energy, external cost of carbon dioxide (CO,) emissions and cost of using cassava-based ethanol as an alternative automotive fuel has been conducted based on its holistic life-cycle, from feedstock production (source) to fuel combustion. And, a new indicator, figure of merit (FM), is proposed for grading conventional gasoline (CG) and cassava-based ethanol (CE): it links net energy yield, external cost of CO' emissions, and production cost (the higher the FM reading, the better the total performance). On the life-cycle basis, the net energy yield of CE is found to be 0.37 MJ/MJ, i.e. about 49% that of CG. The external cost to society of CO, emission of CE is about 83% of CG's, and the production cost of CE is 0.14 RMB/MJ, i.e. about 200% of CG's. The FM of CE is 0.37, i.e. 46% lower than that of CG. From the standpoint of these indicators, CE is currently not competitive with CG, but it has great potential to be improved in the future. (C) 2003 Elsevier Ltd. All rights reserved.