Critique of the Week

Don’t let the post title fool you – I’m not intending on doing a weekly pull-apart of someone else’s ideas or writing.  But…maybe…  Nah, let’s see how this one goes first, shall we?

Now, this gives me no particular pleasure, but I have to get some strong thoughts off my chest with regard to Jeff Tollefson’s article Pilot projects bury carbon dioxide in basalt, published on the Nature website about a week ago.  This isn’t particularly a critique of the work carried out by researchers at the US Department of Energy’s Pacific Northwest National Laboratory (PNNL), although in Scottish parlance, Ah hae ma doots, as you’ll see later.

No, primarily my beef is with the quality of the journalism in the article.  I know one shouldn’t criticise something without having tried it first, and science journalism in particular is fraught with balancing the need to convey complex concepts to lay folk and getting the science right.  So maybe I’m being harsh, and I know I couldn’t easily do his job, but let’s get the gloves off for a minute and give the article a good going over.

The article, in case you haven’t clicked through to read it, is about the sub-surface storage of carbon dioxide in igneous (basaltic) rock, as a means to prevent man-made CO2 emissions from entering the atmosphere.  The first clanger is:

“Until the gas is locked away, the porous basalt layers are capped by solid rock that will prevent leaking.”

Now call me Pedantic, but unless we’re talking about a lava flow or magma, rock is considered solid by default.  Maybe Jeff’s confusing rock with holes in it (porous rock) with foam?  A porous rock is still solid, I would think by anyone’s definition.  I’m assuming then that ‘solid rock’ to Jeff is actually ‘impermeable rock’ to the rest of us, that is, rock which effectively does not allow fluids or gasses to pass through (although not always strictly true, but it’ll do for the purposes of this blog).  In which case, great!  Because that’s exactly the type of rock we need to prevent CO2 stored in the basalt from migrating upwards through buoyancy and back to the surface again!

However, the next mistake immediately follows the previous one:

“That should eliminate concerns about leakage that have dogged other proposals to store CO2 deep underground, often in sandstone reservoirs.”

Um, sorry old bean but the proposed ‘solid rock’ method is exactly the same as that proposed for sandstone reservoirs.  It’s a fundamental requirement of a good CO2 storage reservoir to have a cap of impermeable rock, or ‘caprock’ in the lingo.  Therefore PNNL’s proposal is no more or less risky than other projects, as far as this is concerned.

Next, aside from not explaining why mineralisation is important for reducing risk with regard to CO2 storage – you convert CO2 from something which could leak into immobile minerals – the article seems to confuse the deep mineralisation of CO2 for storage with the mooted commercial mineralisation of CO2 into sellable product:

“And even if a carbon-mineralization industry took off, establishing it on a global level would require an undertaking on the scale of rebuilding the oil industry.”

A carbon mineralisation industry is not what the folks at PNNL or Iceland are looking at (or so I believe).

And the final confusion (sorry, Jeff) seems to be about the storage of CO2 in sandstone reservoirs offshore (i.e. under the sea) versus storage on the sea floor:

“…many are also looking offshore, where the sea floor could accommodate CO2 emissions for centuries to come.”

Technically, you could store CO2 on the sea floor provided it was deep enough for it to remain in dense-phase and so wouldn’t rise back to the surface, but this idea has largely been shelved due, I think, to uncertainties of how you control where the CO2 goes/stays and whether it will dissolve in the ocean to acidify large volumes of seawater.  There is certainly a public acceptance issue with this method and I don’t agree that many are looking at it.  Offshore sandstone reservoirs under the sea, however, is another story and is indeed my broad area of research.

Like I said, I didn’t want to criticise the researchers who were quoted in the article, but some of the claims made are a little difficult to take on board e.g. Juerg Matter:

“you reduce the risk of leakage, and you can pretty much walk away from your storage reservoirs”

I don’t think so, as there would be many regulatory requirements for long-term monitoring, unless you can demonstrate with confidence that you have successfully mineralised or dissolved all your CO2.

Anyway, if Jeff Tollefson reads this, I hope he doesn’t take it personally.  As I said, science journalism is a tough gig, but when you’re writing for one of the foremost science journals you have to get it right and I think his article falls well below the standard I would expect of Nature.  I hope I’ve been constructive though, in my own sarcastic way, and I look forward to having my own science writing pulled apart when I finally get some of it posted on here.

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One thought on “Critique of the Week

  1. Pingback: What’s my PhD all about? (Part 1) | Vitamin CCS

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