[brutos]

I did the calculation myself due to multiple conflicting numbers in this thread: I get 2.6 dollar per gallon of gas (8.65kg CO2 produced by complete combustion of 1 gallon gas):

300$/ton * 8.65kg = 2.6$ per gallon (0.6$ per liter)

100$/ton * 8.65kg = 0.87$ (0.23$ per liter)

30$/ton * 8.65kg = 0.26$ (0.07$ per liter)

7 cent per liter seems quite acceptable. And people are reporting that some companies are targeting that price point for sequestration. Please correct my if I miscalculated something.

[philipkglass]

OP said "by burning a tonne of carbon" rather than "by emitting a tonne of CO2," which is the main reason your calculated per-gallon results are significantly higher than mine. Neither interpretation gets close to $6/gallon in added taxes, so I'm not quite sure what OP meant.