Bob Teixeira decided it was time to take a stand against U.S. dependence on foreign oil.

So last fall the Charlotte musician and guitar instructor spent $1,200 to convert his 1981 diesel Mercedes to run on vegetable oil. He bought soybean oil in 5-gallon jugs at Costco, spending about 30 percent more than diesel would cost.

His reward, from a state that heavily promotes alternative fuels: a $1,000 fine last month for not paying motor fuel taxes.

This is stupid! If I made my own beer or wine, do I have to pay tax on that? How about if I have solar cells... do I need to pay the energy tax on it? I already run my own telecommunications in the house... I don't pay excise tax on it. Hell, I even made my own dinner. Does the government expect an automatic 18% tip?