That seems pragmatic enough to me, and also quite effective. I live in France and, unless I'm wrong, the highest of the oil-related taxes here apply to the consumers, when you're getting gas at the gas station. Instead, your proposition - to apply a $10 tax on the barrel - would apply the same taxation on any fossil fuel usage, be it plastic fabrication, air transportation, electricity generation, etc... That makes a lot more sense environmentally-speaking.