Re: How much CO2 is associated with the use of a barrel of oil

Hi Tom:

There are a few estimates I found by searching the web, and they are around 400 kg or 1000 lbs per barrel (the exact amount probably varies a bit depending on where the oil is from).

In this answer from our archives I tried to calculate about how much CO₂ would come from a barrel of oil, and we can do the backward calculation to see if it matches up (for the sake of brevity, I’ll leave out the math this time). Assuming 1000 lbs of CO₂ per barrel (~450 kg), that is equivalent to 10225 moles of CO₂ per barrel. 10225 moles of C is equivalent to 123 kg of carbon per barrel. In my previous answer I came up with 88.7 kg per barrel, but I assumed a 120 litre barrel of oil. It appears, however, that a barrel of oil is actually just shy of 160 litres (e.g. see here, here, or this answer from our archives). It turns out that 120 litres is the standard size for a beer barrel, I guess that must have been wishful thinking on my part. Scaling up my old answer to account for the larger barrel, I get just a bit over 118 kilograms carbon per barrel. Pretty darned close, especially for a back-of-the-envelope type calculation! So in short, it looks like 450 kg (or 1000 lbs, if you’re not a SI kind of guy) of CO₂ per barrel looks like a pretty fair estimate.

I hope that helps!
Rob Campbell, MAD Scientist (and all around oily character)