That true if the gasoline will cost $0.50. You forgetting that ethanol is heavily subsidize by government. That might be true in Brazil, not in US.. and we are not Brazil.
That not mistake that just build refineries for ethanol closing up because of price of corn and production cost is higher then the profit.
All the fertilizer that they used to improve harvest is base on natural gas or oil.
If you thinking about cellulose base, that only cream on the pie.
With continuous exploration of the land on that scale (you cutting everything and just living the roots) the land will be eroded in not time and then what?
It is already proven that there is not enough land on the world to produce fuel.
And what about food for the people. We already seeing very serious spike in food prices, and what about the 800 million people that face right now starvation in the world.
Do not think the this country is immune to hard ship or even starvation, because you driving SUV and you have good job that pay well right now.
Just let me remind you that grate depression was not just bad dream.
In Europe they preparing for high gas prices for at list 15-20 years that why they do not see such a shock with gas prices at $8-10.
In this country we see $4.5 and we feel like it is end of the world. So what will happen at $7?
People have to understand the faster they adjust the better chance to survival. The adjustment that you have to do not only apply to the car you drive, but also to the home that you own and live (is the home energy efficient), and how far you live from your job.
We also have to reconsider if we really need to buy every three years new car for $30000. My be it will be better if we spend that money to buy solar collectors and wind turbine, so our annual cost for hatting, cooling and in general electricity will go down, even if it pay off in 20 years. You have to remember that 3 years old car loosing like 50% of the value. So what we gaining on that?
Investing in home renewal energy source might also prepare your house for re fueling your future electric car. Just an idea.

The cost for energy going higher and higher every year and do not expect any changes in that trend. Here in NYC the electricity cost is more then $0.3 per kw (including all costs) . In this year they “conveniently” split the used electricity and delivery and rise the prices for both. Same thing happen with natural gas few years back.

As a renewal liquid fuel the only possibility is alga.
It look good , but nobody is really certain if the promises are real – we will see in 2-5 years.
Then there is electric power. We are still behind with that, however there is so much new development in that area that I tend to believe we will start some real revolution in that matter around 2010.
The problem right now is price per KW (right now is like $4000/KW). I believe that it should sharply go down in next two years.
Lithium batteries and other type look more and more promising.
All of that might not be nothing if we not have any force from government. Statement that the market will solve the problem is ridiculous. It will solve in 50 years, do we have 50 years?
As some body said that we need the scale of development that was in WWII in order to get us out from that hole. This country is in mortal danger (not from imaging terrorist) and require wore time approach.
I just hope that we will have smart enough president in January (not the idiot that we have right now) that will go for it.