Leveraging the benefits of ethanol in advanced engine-fuel systems

•Three engine-fuel systems that leverage hydrous and anhydrous ethanol were compared.•Synthetic and fermentation ethanol were both evaluated using the Octane-on-Demand concept.•A high octane E30 gasoline derived from corn ethanol served as the baseline case.•Well-to-wheel GHG emissions were comparable for the three different engine-fuel systems.•Synthetic ethanol could supplement bioethanol in the future transport energy mix.