Difference in RenewabilityEthanol is a renewable fuel made from various plant material called “biomass”.1 It is renewable because the production and combustion of ethanol is a cycle. When ethanol is used, the carbon dioxide and water that the plants use are released back into the atmosphere.2 The water and carbon dioxide can then be used in other plants for there cycles.2 Octane is made with lead and lead is now renewable. So the modern to high octane that does contain lead is not a renewable source.3 How is ethanol produced?Ethanol is produced from biomass mostly by a fermentation process using glucose from sugars, starches and cellulose.4 Fermentation is the process of breaking down a substance using yeasts, bacteria or other microorganisms. Fermentation involves giving off heat to help break down the substance. This process uses mostly environmental factors to create ethanol and there is a large quantity of all these resources.Image 1: Fermentation of Ethanol4How is octane produced?When you take crude oil and break it down you get some hydrocarbons of different lengths. These different chain lengths can then be taken apart and then and put together to make different fuels.5 Methane, propane and butane are all examples of the different fuels that can be made along with octane. It is more work to create octane than it is to produce ethanol because ethanol is mostly all natural resources that are being used in the process.Performance in vehicles:Ethanol is more eco-friendly when it is compared to gasoline, because corn and other plants absorb carbon dioxide from the atmosphere as they grow.6 Then that CO2 can be used in the cycle that creates ethanol. Ethanol is best for vehicles because it cuts the car’s greenhouse gas emissions by a considerable amount, which is better for the earth.7 Gasoline with octane burns a lot of fossil fuels and produces a lot of greenhouse gases.7 A high compression ratio in the engine usually requires higher octane levels in the fuel to prevent premature combustion of the fuel, which is a condition that puts high levels of stress on an engine.8 Ethanol has a higher octane rating than regular gasoline, so it’s a good fit for these efficient, high-compression designed vehicles.8 The equation for combustion of ethanol is:C2H5OH + 3O2 —–> 2CO2 + 3H2OSo ethanol reacts with oxygen to produce carbon dioxide and water.8The equation for combustion of octane gasoline is: 2 C8H18 + 25 O2 —> 16 CO2 +18 H2OSo octane reacts with oxygen to produce carbon dioxide and water.9Cost of each fuel:Ethanol costs about 98 cents per gallon.10Octane Gasoline costs about $1.99 per gallon.10 It may vary depending on the octane level.Efficiency:The energy yield is all the energy produced by the biomass minus the energy used by the fossil fuels. The higher the energy yield is, the more efficient the product is.11The energy yield for ethanol is 1.34 and the energy yield for octane gas is .805. Meaning Ethanol is more efficient. Also, a study done at University of Michigan stated that there is 56% more energy in a gallon of ethanol than it takes to produce it. So using ethanol as a fuel would reduce the use of petroleum which would be good for the earth and is more efficient.12Ethanol Molecule:13Octane Molecule:14 Overall, I think ethanol is a good replacement for octane gas. From my research, ethanol is a renewable resource that cuts greenhouse gas emissions and is more efficient than octane gas. Also, ethanol is biodegradable so if there were ever a ethanol spill it would be degraded into the earth within 5 days.15 Ethanol also costs less per gallon and works very well in vehicles. Ethanol would be a good replacement for octane.