The proper measurement of Energy Density is Joules per kilogram. Not the BTU. This is where physics comes in.<quoted text>
First, gasoline is a mixture of many products. For example, butane is added to gasoline to make it more volatile in winter months so engines start better. Butane has an energy density of 102,00 BTU per gal. Ethanol has an energy density of 76,100 while gasoline has about 112,500 BTU per gal. So we see that ethanol has much more than the 1/5 energy density that you quote.
Would you not add butane because it is an additive? While I do not believe that ethanol from corn is a good alternative to gasoline, it does have some properties that are positive. First, it helps raise the octane number of gasoline. When added to gasoline, it prevents gas line freeze in winter. It helps clean the fuel system, especially dissolving varnishes that plug injectors. Because it absorbs water, it prevents water from collecting in the gas tank.
The main reason that butanol (110,000) has not been more prevalent is because of the low yields from the fermentation process. There are new processes that may promise much better results.
For example, I shall list the energy densities of common fuels used for vehicular propulsion:
Methane 55 MJ/Kg
Aviation Fuel 50 MJ/Kg
Gas 44 MJ/Kg
Natural Gas 38 MJ/Kg
Butane 27 MJ/Kg
and our envirnmental hero Ethanol 26.8 MJ/Kg
What is surprising is the lack of pushing Hydrogen with an energy desity of 142 MJ/Kg!! Over 2-1/2 times that of gasoline.
Anything added to gas with a lower energy density dilutes it and thus reduces its efficiency.(This may be too complicated for professor to understand, however.)
My 12 year old son won a Physics award in the regional Science Fair last year based on this information while showing off his simple water fuel cell. There were judges from NASA present and were highly impressed and thus the award.
I know he can't hold a candle to professor since the professor claims to be the brightest bulb ever created. We can only hope...