kaliber said:
don't know this for sure, but like most combustion of fuel Co2 and H2O is produced, which are exactly the reactants required for photosynthesis (growing sugar canes). Therefore ethanol is renewable
sometimes ethical issues are related to such topics, eg. the ethics behind using a foodsource to convert to fuel when there are millions of people starving
If you consider any fuel that is capable of producing H
2O and CO
2 on combustion as renewable, then that will make octane renewable then (which isn't ... =\ ).
The ethanol's main source of production is energy throughout the process is light energy from the sun, which is renewable as it is more readily available over a long period of time in large amounts (Well, for 5 billion years ...).
Octane's main source of production is crude oil, which takes a long time to produce (millions of years) in small amounts, hence it isn't considered renewable.
xiao1985 said:
^I cannot put it better myself.
A friend of mine did biofuel as a honour project and one of the fiercely debated issue is the fact that huge proportion of land will be dedicated to "grow" the fuel....
and cost wise, it's not cheaper than crude oil yet. and when it is, the supply might not be able to meet the demand.
To be specific (which I'm sure you don't have to), Brazil abandoned the primary use of ethanol as fuel in the 1970's due to the large amount of land clearing.