how can we use alcohol as fuel? & its advantages

we can use ethanol as fuel by mixing with petrol to become power alcohol. Advantages  

• Unlike petroleum, ethanol is a renewable resource
• Ethanol burns more cleanly in air than petroleum, producing less carbon (soot) and carbon monoxide
• The use of ethanol as opposed to petroleum could reduce carbon dioxide emissions, provided that a renewable energy resource was used to produce crops required to obtain ethanol and to distil fermented ethanol

The first four aliphatic alcohols (methanol, ethanol, propanol, and butanol) are of interest as fuelsbecause they can be synthesized chemically or biologically, and they have characteristics which allow them to be used in internal combustion engines. The general chemical formula for alcohol fuel is C_nH_2n+1OH.

There are both great advantages and great disadvantages associated with the use of ethanol as an alternative fuel to petroleum.
  Advantages Disadvantages

• Unlike petroleum, ethanol is a renewable resource
• Ethanol burns more cleanly in air than petroleum, producing less carbon (soot) and carbon monoxide
• The use of ethanol as opposed to petroleum could reduce carbon dioxide emissions, provided that a renewable energy resource was used to produce crops required to obtain ethanol and to distil fermented ethanol

• Ethanol has a lower heat of combustion (per mole, per unit of volume, and per unit of mass) that petroleum
• Large amounts of arable land are required to produce the crops required to obtain ethanol, leading to problems such as soil erosion, deforestation, fertiliser run-off and salinity
• Major environmental problems would arise out of the disposal of waste fermentation liquors.
• Typical current engines would require modification to use high concentrations of ethanol.