Wednesday, June 29, 2022

Direct air carbon capture not a silver bullet for climate change

If anyone was banking on direct air carbon capture technology to save us from runaway climate change, here's a rather large slap in the face. Yes, direct air capture (DAC) works, but it is suspiciously similar to titling at windmills.

The world largest direct air carbon capture faculty, which is currently under construction by Swiss company Climeworks AG in Iceland, and nicknamed "Mammoth", will be capable of extracting 36,000 tons of carbon dioxide direct from the air each year, and deposit it safely underground (or mix it into cement, or use it to produce jet fuel or yoga mats or even fizzy drinks, as some other projects promise). 

That might sound like a lot, and it is nine times more than Climeworks' "Orca" plant, which is currently operational. But it actually represents just 0.0001% of the 36 billion tons of CO2 we as a planet spew into the atmosphere each year. Climeworks sells carbon credits to companies like Microsoft, Audi, Shopify and Boston Consulting Group, but, at €1,000 a ton, they are some of the world most expensive carbon credits (although they do look good on press releases and annual reports). I have not been able to ascertain the actual cost of the plant, other than news of a $627 million partial "funding round", but you have to know it is hugely expensive

At the scale of this (huge and extremely expensive) plant, we would need a million such plants to get us even close to net zero carbon, and that's before we start to reduce our currently unsustainable atmospheric carbon load of 420 parts per million down to a slightly more sustainable 350 ppm. A step in the right direction maybe, but such a small step as to be almost unnoticeable. Climeworks is nothing if not ambitious, and says it plans to build bigger and bigger plants, and to extract a million tons of CO2 from the air annually by 2030, and a billion by 2050.

DAC is currently having quite a cultural moment, exemplified by US President Joe Biden's recent announcement of $3.5 billion for several DAC hubs in the USA, and plans for the first truly large-scale American plant southwestern USA. The most recent Canadian federal budget announced a 60% tax credit for DAC projects. But challenges and problems still abound, including the fact that DAC plants themselves are notoriously power hungry, and not all new projects will be able to utilize Iceland's enviably prodigious geothermal resources, the way Mammoth and Orca do. 

Now, I don't like to dump all over positive news, and I understand that this would be just one plank of many in a climate change mitigation plan (no-one, other than detractors, is claiming that DAC is intended to single-handedly cure all our evils). But we do need to be practical about this, and question whether throwing this kind of money into direct air carbon capture is actually the right thing to do. It seems to me that, dollar for dollar, euro for euro, the money might be better spent on other greenhouse gas mitigation projects. 

I also worry that "negative emissions technologies" of this kind just give high-emitting companies an excuse to keep on polluting, especially given that the technology, while promising, is not guaranteed to become commercially successful. As even DAC companies admit, cutting emissions should always be our first, and overriding, priority.

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