Assessing Ethanol as an Alternative Fuel

Ethanol has been used as a fuel extender as early as the 1950s, however with the rapid drop in oil prices it had been seeing a decline in its use. However, nowadays increasing interest in ethanol has prompted the reintroduction of ethanol. Being clean, carbon neutral and having many benefits makes it ideal as a fuel.

Advantages

  • Ethanol can be produced by the fermentation of glucose, making it a more desirable fuel source as it can be produced from renewable glucose.
  • The presence of oxygen in the molecule means that combustion is almost always complete, meaning a reduction in polluting forms such as CO and soot.
  • The presence of the oxygen also means that toxic additives such as MTBE (methyltertiarybutylether) that helps petrol burn evenly by providing oxygen do not need to be added to the fuel.
  • Ethanol also has the potential to be carbon neutral as the products of its use are exactly those required for its production by photosynthesis.
  • Ethanol has already been successfully applied as a fuel extender without engine damage.
  • Ethanol has a high flash point, meaning it is safer to use on camping stoves as it is less likely to accidentally ignite.
  • Ethanol has a higher RON or octane rating than petrol meaning it burns smoother in high compression performance engines.
  • Ethanol contains no impurities such as sulfur and so produces no polluting SO2.
  • Ethanol is easily transportable and can be easily incorporated into fuel blends.

Disadvantages

  • Ethanol is far more expensive to produce than hydrocarbons used for fuel such as octane.
  • Ethanol has a lower heat of combustion, so more ethanol would be required to travel the same distance as when using petrol.
  • Ethanol has a high affinity to water making it corrosive to fuel lines and engines. The process of distillation thus makes it quite expensive.
  • large areas of land would be needed to grow the biomass needed to produce the ethanol. This can cause environmental problems such as soil erosion, land clearing and deforestation as well as result in losses of large amounts of arable land.
  • Ethanol is corrosive to car engines and fuel lines, and using ethanol above 10% would require engine modifications.
  • The odorous waste products of fermentation are difficult to dispose of.
  • Ethanol has a higher flash point than that of normal petrol, meaning a greater temperature is required for combustion to occur.

Overall, ethanol is currently not viable as a stand-alone fuel source, and can currently only be used as a fuel additive/extender at concentrations of 10%. However with ever increasing need for renewable fuel sources as oil supplies dwindle, ethanol may become important as a fuel alternative in the future.