Reply #14: Thanks, Paul. I will look over your numbers.

[phildo]

The 30% was from numbers I ran with a couple of RE (renewable energy) groups two years ago when I wandered into the RE field from the electrical side (I R an EE).

I do see a couple differences on the modeling assumptions -- we were looking at US v. US (US max production v. US consumption) and also see that you are using the (older) assumptions that Ethanol production methods must be based on traditional (very energy intensive) methods.

My interest into it all was as an application of the large amounts of waste heat the solar electric (boiler not PV) designs I am working on. Turns out the output waste temperatures are optimal for Ethanol production -- about 200 to 190 F. Is useful for both distilling and cooking.

One last difference I see off-hand is the assumption that Ethanol engines produce less energy than gasoline -- that is true for conventional gasoline engines, which are relatively low compression. Engines that are optimized for Ethanol (much higher compression) get comparable outputs.

It also does not consider algae produced ethanol, but as that is still experimental as an industrial CO2 scrubbing method, I do not tend to include it yet, either.

But in all that, please understand I am in no way advocating any attempt near that 15 or even 30% replacement. It is just a way of declaring an upper bound and awareness that even the upper limits of production is WAY below consumption.

My present future fantasy would be a near total electric conversion of ground transportation. How an EE would see the world, huh? :) Trains, trucks, autos -- all pulling their power source from a grid based system -- but that is a whole other topic -- with a whole lot more other numbers. :)

In some post-petroleum future and barring some radical technology breakthrough, the only applications I have seen that liquid biofuels are optimal for are:

Aircraft (depending on overall demand)
Emergency vehicles,
Extreme offroad and some military vehicles, and
Backup and emergency electrical generation.

With biofuels of:

Ethanol, Bio-diesel, and Butanol (a 4 carbon alcohol that behave much like gasoline)