According to the feds, almost 60% of the cost of diesel fuel is the cost of crude oil; when crude costs go up, diesel costs go up. Crude's pushing $100 per barrel again, so yeah it's getting expensive again! Almost 30% goes to refining, distribution and marketing. Federal, state & local taxes are about 12% of the cost.
Government-mandated ultra-low sulphur diesel fuel, production of heating oil in the winter, and the demand for overseas exports (yeah, we sell off a lot of our diesel fuel) keep the cost of diesel high, especially in the winter as we're seeing now.
Exxon (for example) made about two cents profit per gallon of fuel (gas or diesel) sold in 2010. Compared to that, grocery store profits of 2-3 PERCENT seem pretty excessive, eh? Why are we complaining about Exxon and not Piggly Wiggly?
Sorry, p*ss & moan about the oil companies all you want. But between our "friends" overseas from whom we buy crude oil, and our government that (a) restricts exploration & development of our own oil resources, (b) creates restrictions and regulations that increase the cost of fuel production, and (c) adds 12% to the cost of fuel by taxation, we are pretty well screwed here. Few of us want to find another lifestyle, so we grit our teeth, buy the diesel fuel and spend less at the tables in Vegas... Jim....