Also, I've looked for the past week at the effects and up/downsides of
Ethanol vs. Butanol. This thread was one of the last things I did
searching for my answers.

I am still seeking downsides to butanol, but again, aside from the odor
during production and the possible hard starts in cold wheather with a
95 degree flashpoint, and the toxicity (not more toxic than gasoline,
however), the only other con I can find was it's high cost of
production. The new processes using fibrous fermentation beds have
changed the cost of production ($1.05 - $1.25/gallon using corn
feedstock) AND yeilds per bushel of feedstock to the same as ethanol,
only with higher energy yeild per gallon of fuel.

Using a feedstock such as dairy waste from cheese manufacturing reduces
the production cost per gallon of butanol to approximately $0.50 per
gallon.

Again, if you know of links to more downside information on butanol,
please let me know. I'm considering forming a co-op to investigate
butanol production for the personal use of co-op members in my area.

Till