Bio Diesel Prices

I have a question that I hope someone out there has a good answer to.

I was driving through Phoenix, and passed the Phoenix Organic Biodiesel store. Their price per gallon was $5.40.

Now a year ago, the price was about $2 less per gallon.

Now to the best of my knowledge, biodiesel is not made from oil. Oil prices rise, according to the media, beause the price of a barrel of oil rises.

Why then does the price of a gallon of biodiesel always seem to be set about $1 a gallon more than regular diesel?

It looks to me like a tax on doing the right thing.

Somewhere in this town there must be a budding investigative reporter who wants to get to the bottom of this, and report it in the locals guide. Someone to prove that it is, or is not a conspiracy.

Someone could be the reporter to bring the first pulitzer prize for jounalism to the locals guide.