Carbon Capture. Getting behind the hysteria.

Carbon capture is in the news again, as the new Labour government announces a substantial new programme for the development of the technology. This has attracted a barrage of criticism from both Left and Right, in spite of the fact that carbon capture is widely regarded as an essential component of any mitigation strategy. So it’s worth exploring a bit further.

 

Some technical background.

 

We should get the terminology clear. There are many approaches to carbon capture, including the use of natural processes in the carbon cycle, for example by improved land use, planting trees or through various “geo-engineering” schemes to increase the “fixing” of the carbon in the oceans.  Greens and others, unsurprisingly, tend to favour the most “natural” and least environmentally intrusive of these. 

 

Second, when CO₂ is captured, it can either find a useful purpose, or it can be sent to a safe permanent store. Use in the soft drinks industry will be trivially small, but it can also be used in the production of synthetic fuels. Most recently there has been a lot of interest in synthetic aviation fuel (SAF) for the hard-to-decarbonise aviation industry.

 

Trees are one form of direct atmospheric carbon capture (DACC). But there are also industrial process approaches to direct capture, sometimes referred to as mechanical trees, which rely on established chemical techniques to separate CO₂  from the atmosphere. It’s claimed that the cost of DACC and subsequent storage (DACC+S) could be brought down to below $200/ tonne, a level that could imply total costs of emission-free oil use well within the historical range of oil price variations. Proposed options for storage include geological formations such as depleted oil reservoirs  and the deep oceans

 

Problems with and arguments against the various DACC methods include:

 

·       excessive requirement for land use, sometimes in competition with food production; this will apply to some but not all methods of both a “natural” and industrial nature; this places an upper limit on what they can achieve

·       excessive land use can also have ecological and human rights implications

·       unproven nature and potentially high costs, and, in the case of natural methods, science unknowns around whether particular land-use policies will be net emitters or receivers of CO₂

·       for industrial methods, high energy use requirements

·       the argument that carbon capture is a distraction from the preferred alternative of eliminating fossil fuels

·       in relation to storage, doubts about suitability of locations, safety and permanence; transport of CO₂and injection into storage may also be expensive

 

The above has all been about direct air capture. However it is, for obvious reasons, likely to be much easier and cheaper to capture high concentrations of CO₂  at the point of combustion when it is released from the fossil fuel. A Green version of this technique involves the use of sustainable bio-fuels, known as bio-energy carbon capture and storage or BECCS. BECCS is likely to be severely supply limited in relation to the scale of what is needed. More generally carbon capture can be fitted or retro-fitted to fossil burning plant, including power generation, and this has generally been the main focus of carbon capture and storage policies, usually referred to as CCS.

 

An additional issue for CCS is that it is likely to be less than 100% effective, with a leakage rate of perhaps 10% or more, so it is not a silver bullet.

 

Is carbon capture an essential component of climate strategies?

 

The IPCC is fairly clear that carbon removal, ie DACC, will be an essential component of any feasible route to a sustainable future. It also endorses continued use of fossil fuels, where this is accompanied by CCS, as one of the options for getting to a net zero future. CCS is also supported by the UK Committee on Climate Change (CCC) as part of a UK strategy aimed at this objective. Both these bodies have the advantage of access to a huge body of scientific and technical advice on the subject, in the context of means to mitigate climate change.

 

So should the UK government be promoting CCS?

 

On the basis of IPCC and CCC advice, the principle of promoting CCS seems to bejustified. There may be alternative means of getting to net zero, but if this is the quickest and cheapest option, then there should be no reason to object to it. Moreover this will not just be a UK issue. Much of the world is even more locked into fossil-based technologies than the UK, so the potential of CCS as an interim or transition technology may be quite important.

 

Whether it has a positive contribution to a UK industrial strategy is another question. Potentially the answer is that it does. Countries like Germany have a much higher lock-in to fossil fuel. But as ever, geography and trading relations matter. Not all countries will enjoy the storage options that the UK has, and Brexit will make the potential to exploit European markets harder.

 

Finally there is a history to this. In 2015 the Cameron/ Osborne government cancelled a CCS programme after the spend of £ 100 million of public money and substantial private sector investment of time and resources. This was part of a major rolling back of  Cameron’s Green promises and accompanied the slashing of budgets on other “easy win” measures such as home insulation. As a marker of determination to take net zero seriously, the Labour government's move is a welcome step. But it does not detract from the need to continue to explore the wider DACC options for carbon removal and storage, nationally and globally.