Bioethanol is an alcohol made by fermenting carbohydrates from plants like corn or sugarcane. It can be used as a gasoline substitute. Bioethanol has lower energy content than gasoline but has higher octane numbers. It is produced through processes like sugar or starch fermentation. While bioethanol reduces greenhouse gases, there are concerns about food prices and land use. Future development focuses on using non-food feedstocks like cellulosic biomass.