I have been corrected by numerous people who have studied this subject for amny years and in great depth. I have been informed that I was underestimating. The 7.5 kwh is for a US gallon, in the UK it is 9 kwh and all the figures I have seen estimate the total amount of electricity used by the refining industry is very close to 20% of our total consumption.
That said, I am very impressed by your breakdown and what ever the actual figure, we do use a lot of electricity to refine petrol. Is the carbon output of this figure included in the 'tailpipe emissions' of a 'super, eco, econobox diesel' No, of course not. My argument has always been that the C02 output figures are pure fiction, in just the same way as 'zero emissions' are fiction. My argument is, if we charge an electric car off the UK grid today, there is a carbon element in that power, but no where near as much as a rattle old internal combustion engine.
Finally again, I like your thorough take on this subject, I think we could get along. if you're on twitter I'm @bobbyllew