Re: A hypothetical question

I'm not going to claim that the site I found is correct. I just came across it by searching with Google. But the total mass of coal isn't carbon, so the total carbon dioxide produced should be less than the 3.7 tons you calculated per ton of carbon. According to Wikipedia, the carbon content of bituminous coal is around 45–86%, while the 4,172 lbs of CO2 from the site is 2.1 tons, or about 57% of what you calculated based on a ton of coal being a ton of carbon. This puts the number well within the range of carbon content in coal. There also is probably some carbon that doesn't completely burn which may be left over in the ash and clinkers, which further reduces the CO2 produced per ton of coal.