Answer: Biofuels #Octane
Replacing fossil fuels with biofuels—fuels produced from renewable organic material—has the potential to reduce some undesirable aspects of fossil fuel production and use, including conventional and greenhouse gas (GHG) pollutant emissions, exhaustible resource depletion, and dependence on unstable foreign suppliers. (EPA.gov)
First generation biofuels are made from sugar crops (sugarcane, sugarbeet), starch crops (corn, sorghum), oilseed crops (soybean, canola), and animal fats. Sugar and starch crops are converted through a fermentation process to form bioalcohols, including ethanol, butanol, and propanol. Oils and animal fats can be processed into biodiesel. Ethanol is the most widely used bioalcohol fuel. Most vehicles can use gasoline-ethanol blends containing up to 10 percent ethanol (by volume). Flexible fuel vehicles can use E85, a gasoline-ethanol blend containing up to 85 percent ethanol. There were more than 2300 E85 fueling stations located throughout the US in 2013 (US Department of Energy).
Second generation biofuels, or cellulosic biofuels, are made from cellulose, which is available from non-food crops and waste biomass such as corn stover, corncobs, straw, wood, and wood byproducts. Third generation biofuels use algae as a feedstock. Commercial cellulosic biofuel production began in the US in 2013, while algae biofuels are not yet produced commercially.