Again the disclaimer on not being legal counsel applies, but...

Excise Tax

There is a fascinating implication of operating a motor vehicle on an alternate fuel. If the excise or fuel taxes have not been paid by the energy provider (including you if you made it, blended it, etc.) then you are liable for the excise taxes on the portion of the fuel that is blended with already taxed fuel (more).

There is some help understanding the implications but you need to consider this landscape is constantly changing.

• DOE info here

• IRS info here

Tax Credits

• Hybrid Cars and Alternative Fuel Vehicles

• Excise Tax Filing Instructions

• Alternative Fuels Excluding Ethanol and Bio Diesel

• Alcohol Fuel Mixture Credit

• Bio Diesel Credit