This analysis quantifies the economic feasibility of cellulosic biofuel pathways under fossil fuel price uncertainty. Eight pathway scenarios are developed on the basis of existing techno-economic analyses and projected fossil fuel commodity prices from the Energy Information Administration's (EIA) 2010 Annual Energy Outlook (AEO). A 20-year net present value (NPV) is then calculated for each pathway scenario. Uncertainty distributions are developed for each pathway scenario by fitting historical monthly price variance distribution curves for each fossil fuel commodity to their projected annual prices. Finally, a sensitivity analysis is completed by replacing the EIA's AEO 2010 projected prices with those from its AEO 2013, the latter incorporating recent exploitation of U. S. shale gas reserves into its projections. The results of this analysis indicate that fast pyrolysis scenarios see the greatest increase in estimated NPV value followed by gasification and acetic acid synthesis scenarios. Fischer-Tropsch synthesis scenarios remain largely unaffected by the updated EIA projections. Methanol-to-gasoline and enzymatic hydrolysis NPVs decrease as a result of lower projections for fossil fuel prices. (C) 2013 Elsevier Ltd. All rights reserved.