I want to make a project on bio-ethanol fuel for automobiles?

Question

Bioethanol gives a 70% carbon dioxide reduction versus petrol. This means that a 5% blend produces 3.5% less carbon emissions, whilst an 85% blend (like E85) would achieve a 50% reduction.

Answer 1

No, bioethanol does not.  It's actually quite bad for the environment.  You have it confused with biodiesel, which is good.  

Here's what the government says

http://www.mda.state.mn.us/renewable/ren...

As you can see, they burn 1 joule of fossil fuel to make 1.34 joules of ethanol.  (a "joule" is a unit of energy - what actually makes your car move.  It's hard to compare by gallons, because ethanol has less energy per gallon.  But a joule is a joule.)  

Biodiesel is worlds better - burn a joule's worth of fossil, get 3.2 joules of useful fuel.

Don't laugh, they're actually building coal power plants in the midwest to power all the ethanol plants... it makes no sense for the environment, but it's American coal making American jobs and reducing dependence on foreign oil.