[Yardstick]

Plants can take solar energy and convert it to a storable medium very efficiently.

That's what I figured. It's easy to store corn energy. Just fill a silo with corn or fill a tanker with ethanol. No batteries required.

Here's another question for you (if you don't mind):

Since plants store energy as carbohydrates, why isn't it a simple process to convert them into hydrocarbons? After all, they're both just carbon and hydrogen bonded together. Why do we have to turn the carbohydrates into alcohol, which has the disadvantages of low btu's and being water soluble? Why not just turn the starch into oil (or gas)?

[P-40]

Since plants store energy as carbohydrates, why isn't it a simple process to convert them into hydrocarbons?

You can convert to hydrocarbons for biodiesel. I think for gasoline you have to create the alcohol because that is the only way it will work.

This is from biodiesel.com

Technically, biodiesel is Vegetable Oil Methyl Ester. It is formed by removing the glycerol molecule from vegetable oil in the form of glycerin (soap). Once the glycerin is removed from the oil, the remaining molecules are, to a diesel engine, similar to petroleum diesel fuel. There are some notable differences. The biodiesel molecules are very simple hydrocarbon chains, containing no sulfur, ring molecules or aromatics associated with fossil fuels. Biodiesel is made up of almost 10% oxygen, making it a naturally "oxygenated" fuel.

Biodiesel is the only product known to the State of California to not cause cancer. :)