re: #473 jaunte

I was wondering yesterday while reading some of the arguments about
Keystone, how much of an impact it would have. Some estimates show that the Keystone XL oil pipeline may bring another 830,000 barrels a day to U.S. refineries.
Not all of the refined product will be staying in the country.

In 2009 U.S. consumption was 18,690,000 barrels a day.

What’s the efficiency of bitumen refinement? I know it takes a lot of tar sand to make a barrel of oil, but how much energy goes into the process prior to refinement into fuel?