I think there is a place for carbon capture and utilisation. But just not the way we have been thinking or approaching it. Carbon capture and storage in some kind of cavern or project and expecting it to hold on to the carbon dioxide does not make sense. But many other carbon sequestration approaches do: applying biochar to ground, injecting carbon dioxide into cement to strengthen the concrete, or any processes that somehow mineralises carbon dioxide into some kind of other compounds including carbonates.
All of the approaches where carbon dioxide is somehow transform into some other form which is more permanent and serves a function make sense. The technologies involve in terms of filtering the carbon dioxide to a certain level of purity, conveying it and handling it, will play important role in the low-carbon economy.
The reason is that carbon dioxide is still an essential part of many industrial production processes. In any case, the main challenge of climate change isn’t really the presence of carbon dioxide – it is the fact that we are taking out fossil carbon and then turning it into carbon dioxide, releasing it into the atmosphere faster than it can be cycled back into other parts of nature. This build-up of carbon dioxide, strengthens the greenhouse effect, making things really nutty for the climate.
But when we are taking biogenic carbon dioxide and using it, there is nothing wrong because the carbon was sequestered from present carbon dioxide in the atmosphere. Using it merely ‘recycles’ the carbon around. Human systems that does carbon capture can play that same recycling role. Take for example the capture of biogas from the anaerobic breakdown of organic matter. That is a mix of methane and carbon dioxide gas; the carbon dioxide gas can be filtered out and then used for industrial processes, while the pure methane (or biomethane as we call it) can be used for energy purposes – combustion to produce heat and drive turbines to produce electricity.
Moreover, the carbon dioxide produced from combustion can be captured, purified, and utilised just like the carbon dioxide filtered out from the biogas. This carbon dioxide can actually be combined with green hydrogen to form many other hydrocarbon molecules that act as our more familiar fuels that are compatible with many of the engines and systems we have. Not just that, the combusted fuel will emit that same ‘biogenic’ carbon dioxide, which would not count as greenhouse emissions because they are in the short-term cycle. Nevertheless, we can still capture that carbon dioxide and then return it to those uses we talked about.
To me, that’s the role of carbon capture in the future – it is really to recycle the carbon just as nature already does it. It is not to erase the carbon dioxide that has already been emitted. It is really naive to think that spending more energy trying to capture the emitted carbon dioxide can be more worthwhile than using alternative forms of energy that do not emit so much carbon dioxide in the process. That would be the role of these technologies in the future.