hmmmm with this one, to summarise its use as a car fuel, u might want to do a case study or get some detail into brazil, where most cars there use a combination of both normal octane petrol and ethanol. might also want to research different blends of ethanols, and what vehicles use it (e.g. trucks, vans, sedans, etc...).
to EVALUATE its usage, u might want to consider the chemistry involved with combusting ethanol rather than petrol (seeing that ethanol overall is a 'cleaner' fuel), how it is used as an industrial solvent, and an important beverage.you would also have consider how its lack of more widespread use is attributed to its high production cost (need large areas of land to harvest crops for fermentation), it is inferior to petrol in some respects, and that most engines arent able to cater for ethanol, or risk engine damage.
IMPORTANT must weigh up the pros and cons of using ethanol and make judgement on it. extra, RECENT information (e.g. being able to add extra parts to engines so they can run on ethanol) will sway ur decision whether ethanol in future is bad, or good.
personally, it is a good thing, because it is a leading fuel alternative to petrol, and is becoming increasingly more economically viable considering the rise of petrol prices and the slow, steady decline of world oil supply to meet demands.
*phew* that was a mouthful...
