Oil Companies and Climate Change Redux
A while ago I received an email from a friend asking whether or not I had a number for the amount of CO2 emitted by a barrel of oil. I searched for a while but couldn’t turn up anything definitive. So, given I know a little bit about the subject, I decided to work it out myself. The calculations can be found here: Oil Companies and Climate Change. After a few conversions, it turns out that the amount of CO2 produced by the liquid fuel products of an average barrel of crude oil is 317kg.
That’s simple enough and is pretty uncontroversial, I believe. The calculations themselves are not difficult, and anyone who paid attention in high-school chemistry should be more than capable of them. The only thing that made my calculations in any way noteworthy is the fact that I appear to be the first person to have published them in an easily accessible (via google) place. Nothing more.
I then took that 317kg (which was the primary goal of my work, as it’s a useful reference figure) and applied it to a specific real-world project. In this case, the Peterhead / Miller Field carbon capture scheme proposed by BP. According to the BP press release:
Injecting the carbon dioxide into the Miller Field reservoir more than three kilometers under the seabed could extend the life of the field by about 20 years and enable additional production of about 40 million barrels of oil that are not currently recoverable.
And in the following paragraph:
The project would also permanently store 1.3 million tonnes of carbon dioxide, the equivalent of removing 300,000 cars from the roads.
Based upon these figures, provided by BP, it is clear that the 40 million barrels of oil will generate (multiply by 317kg) approximately 12.68 million tonnes of CO2. Which clearly dwarfs the 1.3 million tonnes that BP claims will be stored.
My calculations were cited by George Monbiot in a recent Guardian article, as a demonstration that the claims being made for carbon capture are somewhat dubious.
However, in a response to Monbiot’s piece (via Tim Worstall) comes this:
In 2005 BP proposed to build a new gas-fired power station at Peterhead, capture the carbon dioxide produced and use it for enhanced oil recovery in the Miller field below the North Sea; this innovative project could have been up and running in 2009. Monbiot is wrong to suggest that the plan would have led to more carbon emissions than savings: between 1.8m and 2m tonnes of carbon dioxide would be injected each year over 20 years, producing an additional 40m-60m barrels of oil. Taking the higher numbers, 40m tonnes of carbon dioxide remains underground, while burning the oil produces approximately 20m tonnes; twice as much carbon dioxide is stored than emitted.
The abandonment of the Miller scheme due to lack of government support means a loss of $6bn in oil revenues and a missed opportunity to take a lead in reducing carbon emissions.
Professor Martin Blunt
Department of earth science and engineering,
Imperial College London
The important piece to note here is: “between 1.8m and 2m tonnes of carbon dioxide would be injected each year over 20 years”. While this doesn’t affect my “carbon-per-barrel” number, if true, then clearly it radically alters the figures for the BP project under discussion.
I’ve spent the morning on the phone to various people in BP (you would not believe how difficult it is to track down someone who knows what they’re talking about, let alone someone who has even heard of the project in question) and was eventually informed that contrary to the statement in their press release, the 1.3 million tonnes is indeed a per annum figure (they don’t know where the 1.8 to 2 million figure came from, but they do claim 1.3 million per annum).
This — if true — invalidates my claim that the project would produce far more CO2 than is captured. Worse, far worse, it undercuts Mr. Monbiot’s article and I feel completely sick about that. In my defence, I was carrying out my calculations based upon figures published by BP, and I’m not sure I should have expected them to grossly underestimate the amount of CO2 being captured by their own scheme. But all the same, I’m afraid I must apologise to all concerned, particularly George Monbiot. There’s few things worse than being responsible for errors in someone else’s work. Really makes you feel like crap.
http://www.bp.com/genericarticle.do?categoryId=2012968&contentId=7006999
First Google result relevant to a search for “BP Peterhead”.
” When fully operational, the project would be expected to capture and store around 1.3 million tonnes of carbon dioxide each year and provide ‘carbon-free’ electricity to the equivalent of a quarter of a million UK homes. ”
But well done on the correction. Would that all writers (myself included) were as willing to be up front about errors.
March 20th, 2008 | 1:53pm
by Tim Worstall
Tim, I went directly to the BP site and drilled down into their hydrogen section to discover the numbers. I do accept that the calculation was incorrect based upon the revised numbers, but I also believe that BPs publication of the incorrect data (albeit as well as the correct stuff) is a mitigating factor.
I carried out the work in good faith and using data published by BP. Obviously if I had any reason, at the time, to suspect they were under-estimating their own claims, then I would have sought further confirmation.
March 20th, 2008 | 2:07pm
by Jim Bliss
My magic fag packet says 1 barrel = 159 litres, oil is 20% lighter than water, call it 127 kg in weight. Oil is nearly entirely carbon (atomic mass 12) and it combines with two oxygens (atomic mass 16) to form CO2, so the C02 produced by burning one kg carbon = 3.66r kg. 127 times 3.66r = 466 kg.
March 20th, 2008 | 3:44pm
by Mark Wadsworth
That’s inaccurate, Mark. First of all, less than 80% of the average barrel of oil is refined into liquid fuel. Of the rest, much of it becomes road-asphalt, plastics, lubricants, etc. etc. These (generally) do not end up as atmospheric CO2.
Furthermore, a barrel of crude will generate a range of different liquid fuels of different specific gravities. For the sake of greater accuracy, it’s worthwhile performing the calculation separately for each of these fuels and then combining the totals.
EDIT: It’s also worth pointing out that your figure of 3.66 is higher than the 3.15 provided by this Oxford University study (pdf file). Though given my luck today, it won’t surprise me to discover that they’ve got it wrong too.
March 20th, 2008 | 3:49pm
by Jim Bliss
The figure of 1.3 million tonnes a year for 20 years means 26 million tonnes would be stored.
The 40-60 million barrels of oil would release between 9.51 million tonnes (your lowest number for 40 million) and 20.93 million tonnes (your potential maximum per barrel x 60 million).
Add to that the 10% of the emissions that were never going to be captured in the first place, and the project would be responsible for between 47% and just over 90% of the emissions of a conventional gas-fired power station.
Whilst not as shocking as your original incorrect figures, it is still a serious amount of emission and gives the lie to BP’s claims of it being ‘carbon free’.
The idea of carbon capture has some serious potential, but the corporations doing it will always do it in the most profitable way they can. Their carbon accounting will be done with the same attitude as their financial accounting. Any loophole will be exploited. There would need to be complete-project emission figures for it.
March 20th, 2008 | 4:04pm
by merrick
Tim Worstall, incidentally, left a comment on Monbiot’s piece saying ‘There’s nothing immediate nor catastrophic about climate change. We’ve time for the technologies in development to mature.’
The threshold of ‘tipping point’ is very widely accepted as a global temperature increase of 2 degrees above pre-industrial levels. That means keeping atmospheric CO2 levels at around 400parts per million or below. We’re already at 380ppm, and rising at about 2ppm annually.
we need reductions in global emissions within ten years, then. which means any technology must be developed and widely deployed by then. Pretty fucking immediate, I’d say.
He’s right that climate change isn’t catastrophic. Yet. but by the time it starts to get really bad, it’ll be too late for effective remedial action.
If you drive off a cliff you don’t sustain injury until you hit the rocks below. but it’s no use deciding to turn around when you’re over the edge.
March 20th, 2008 | 4:07pm
by merrick
[…] Miller Field CCS project). For details of this error, please read the correction / apology: Oil companies and Climate Change Redux. For the calculation estimating the quantity of CO2 emitted by a single barrel of oil, please see: […]
March 20th, 2008 | 5:16pm
by The Quiet Road » Blog Archive » Oil companies and Climate Change
“The threshold of ‘tipping point’ is very widely accepted as a global temperature increase of 2 degrees above pre-industrial levels. That means keeping atmospheric CO2 levels at around 400parts per million or below. We’re already at 380ppm, and rising at about 2ppm annually.”
I agree it’s widely accepted. I don’t agree that it’s true. There’s nothing in the IPCC reports (which, I assume, we’re all using as our baseline) to say that it is.
More importantly, above about Jim’s defensiveness about his calculation. Please, don’t be so: I like and admire lots of your writing, I disagree with other parts of it. But I’m not counting coup in having shown you to be “wrong”. “You”, “We”, “I” “Us” will get to the truth about such matters: as I was rightly corrected on my response to that Lancet report. Jim was righteously corrected here.
And thus do we find truth.
I assume that is what we’re all after?
March 20th, 2008 | 9:25pm
by Tim Worstall
Tim, I’m not sure I’m being overly “defensive” about my calculations (though it’s impossible to say that without sounding overly defensive). Within a couple of hours of discovering my error (long enough to confirm that it was in fact an error), I posted an immediate retraction.
However, I genuinely felt it important not only to explain that my work contained an error, but also to explain what that error was and why it occurred.
I was absolutely mortified by the thought that someone might think I deliberately “cooked the numbers” given my history of criticising the oil industry. There are certain less-than-fair-minded individuals who would be more than willing to imbue my “error” with an agenda. That’s the kind of thing that sinks careers (and rightly so if such an agenda did exist and resulted in deliberate falsification).
That’s the only reason I’m bending over backwards to make it clear where and why the mistake happened. Seriously, you’ve no idea how sick I feel about this mess.
March 20th, 2008 | 9:35pm
by Jim Bliss
“Seriously, you’ve no idea how sick I feel about this mess.”
My point exactly. You shouldn’t feel “sick” about this. A mistake was made, a mistake was pointed out, a mistake was acknowledged.
Excellent, knowledge moves forward, we all know more than we did before. What’s not to like here?
Sure, all of us (and I’ve made similar mistakes) would prefer that the mistake was never made, but being infallible is given to no man except that bloke in Rome.
Seriously, buck up! That you were in error shows that you are human. That you agreed that you were in error, that you corrected it, shows that you are, well, given your political views, perhaps you don’t think that “gentleman” is quite the compliment that I think it is. Would “mensch” be an acceptable substitute?
I do, of course, as you know, disagree with you on many matters. This one though? It’s not a matter of disagreement, it’s an error, and neither you nor I, nor anyone else, is going to progress from here to the grave without making some of those.
What matters is how one deals with them and, for what little my opinion is worth, you’ve done exactly the right thing.
Good man, well done.
March 20th, 2008 | 10:34pm
by Tim Worstall
OK, knock off 20% from 466 kg and we get 373 kg, let’s not split hairs, maybe the figure you used of 315 kg is correct (bearing in mind that some of oil is hydrogen and other stuff, it’s not pure carbon.
However, another daft mistake you made was 40 million barrels x 317 kg = 12.7 million tonnes.
Don’t forget that 1 barrel = 127 kg.
So that should be 40 million x 127 kg x 3.17 = 16.1 million tonnes. Which is close to the prof’s figure of 20 million (which is presumably a mid figure between CO2 caused by 40 million and by 60 million barrels)
That said, I don’t believe for one second that you can compress CO2 to such a degree that it displaces more than 3.17 times its own weight in oil. But happily, I don’t believe in MMGW any more either.
March 20th, 2008 | 10:40pm
by Mark Wadsworth
Thanks for that, Tim. As I say though, it’s not so much the error that got to me as it is (a) the possibility that it might be misinterpreted (maliciously or otherwise), and (b) the fact that someone I respect (George Monbiot) cited the calculations to support a position.
You’re absolutely right though; to err is indeed human.
You’ve confused me there Mark (it’s been a long day). That “40 million x 127 kg x 3.17 = 16.1 million tonnes” thing; I don’t see what you’re getting at.
Assuming the 3.15 multiplier is correct (and I’ve double-checked it and believe that it is), then, having established that a barrel of crude oil contains 100.73kg of liquid fuel (see http://numero57.net/?p=255), it stands to reason that one barrel will emit 317kg of CO2 when consumed.
To get the total emissions from X barrels, then, seems to be a simple multiplication.
I was wrong about the amount of CO2 being captured, but I’m pretty sure I’m right on this.
March 20th, 2008 | 10:51pm
by Jim Bliss
You are right, one litre petrol = 2.4 kg of CO2, one litre weighs 750g, so one kg petrol = 3.2 kg C02. A bit less than 3.66r, but hey!
One barrel = 159 litres, weighs 127 kg, 20% lost in processing (or not burnt) = 100kg (which agrees to your figure).
So, yes, 40 million barrels = 13 million tonnes CO2.
Anyway, what’s 40 million barrels between friends? Global oil usage is 80 million barrels per day, so whether it runs out on 17 May 2083 at 3 in the morning or 3 in the afternoon is neither here nor there.
March 21st, 2008 | 1:27am
by Mark Wadsworth
A friend of mine based his whole PhD thesis on a paper of some other (highly distinguished) scientists. In the final months while he was polishing it up for submission, they publicly admitted to a crucial mistake in their work, which in turn brought his entire thesis crashing to the ground.
It sucks hole, but it happens. I know the profs felt shitty screwing over a student like that. But he got an extension, and got on with redoing his research – which turned out well (if a year or two late) – and bore no grudges. He’s now a very successful researcher in his own right.
March 25th, 2008 | 7:17pm
by Larry Teabag
Hi guys, good work in your astute calculations and checking of calculations which appears to be being pursued on an entirely voluntary basis.
I am currently trying to find out if there is any information available with respect to the carbon emissions generated from the capture, transport and storage of carbon.
Im looking for info such as the CO2 produced (or energy used) from:
– processing the raw emissions,
– pumping the refined carbon through an overground pipeline (ie. energy used/kilometre of pipeline)
– shipping the carbon out to an offshore depleted oil well
– pumping the CO2 into the oil well
I suspect theres no easy answer or reference point but its worth asking.
Thanks
Brendan
May 12th, 2008 | 3:27pm
by Brendan Tapley
Hi Brendan, thanks for your comment. I’m afraid though, that I’m unaware of any data on the energy consumed (and/or the carbon dioxide produced) by Carbon Capture schemes. But it’s probably worth pointing out that no two schemes will produce the same numbers. For instance…
– processing the raw emissions
Processing the emissions from coal burning will require more energy than processing natural gas emissions (thanks to the high quantities of other gasses, specifically sulphur dioxide, which need to be dealt with when coal is burnt). Oil will probably fall somewhere in between. Though obviously, that’s just a best guess.
– pumping the refined carbon through an overground pipeline (ie. energy used/kilometre of pipeline)
That’ll vary wildly depending upon the diameter of the pipeline and the gas pressure employed.
– shipping the carbon out to an offshore depleted oil well
Depends upon how far out the well is. Also, chances are it’ll be transported by pipeline rather than ship. And in the case of onshore oil wells, no shipping or offshore pipework will be required.
– pumping the CO2 into the oil well
Will depend upon a variety of factors such as local geology, well depth, injection pressure, and more.
All in all, it’s a very complicated can of worms you’re opening here. But one that certainly needs to be opened. Individual CCS schemes are ripe for this kind of analysis, but I doubt there’s going to be a “typical” figure for CCS schemes in general, and any average or mean value derived from comparing several schemes may well be meaningless if applied to any specific scheme.
Having said that, the place I’d advise you to check out for further research would be the [energyresources] mailing list.
http://tech.groups.yahoo.com/group/energyresources/
You can search the archives without joining the group. I can’t guarantee what you’re looking for is in there, but it might point you in the right direction.
May 12th, 2008 | 4:04pm
by Jim Bliss