It is an alternative energy, but not a long term solution to energy needs

Implications: Ethanol as an energy source is not as cost efficient as we think.
Cost of water, fertilizer, transportation, blending and subsidies detract from its attractiveness.
In the long term we cannot produce enough renewable energy to make a signifigant dent in our energy demand.
Corn and rape seed as feed stock are not likely sustainable as biofuel inputs.

Analysis:

Farm production is already subsidized.  The ethanol subsidies just add another layer of inefficiency.

When you consider the cost of water in irrigated fields, fertilizer, fuel for farming, fuel for harvesting and transporting the biomass, and then the energy for production of ethanol it is not cost efficient.  To that you will have to add the cost of ethanol product transportation, distribution, storage and blending.

Already other users of corn and crop land are feeling the pinch from expanded use of corn as an ethanol feed stock.  Chicken and beef prices will be affected.

When US fuel consumption increases, what are we going to do to keep pace?   Will we plow up forests or prairies and recreate the dust bowl?  Will we lower ethanol import tariffs and cause others to plow up rain forests?  Can we maintain the subsidies for ethanol producers in the long run?  Economic theory says no.