Educate Yourself seruzawa
Before posting you might want to educate yourself a little bit on alternative fuels. The man in the story is not using biodiesel, he is using straight-vegetable-oil (SVO).
Biodiesel is a refined product that takes vegetable oil and removes the glycerin so that you can burn it in a diesel engine without modification or risk of gelling. Most biodiesel is made by companies or co-ops and is taxed just like regular fuel though you can by kits to home-brew biodiesel from SVO. I use biodiesel in my VW TDI when it is available and have no problems with the government because I pump it at a gas station just like everyone else and pay road taxes.
SVO is just what it sounds like, vegetable oil that has not be refined. If used in a diesel vehicle without modification it will solidify or gel causing the engine to stop running. To avoid this, people install dual tank systems in their cars that allow the vehicle to start and stop on regular diesel and then switch to SVO for cruising once the SVO has been heated to a temperature that allows it to flow freely. This is what the man in the story was doing and was fined because he didnt follow proper channels.