Capturing concentrated emissions at source is easier and more cost-effective than capturing them when they have dispersed into the air
Carbon capture and storage (CCS) involves three major steps: capturing CO2 at the source, compressing it for transportation and then injecting it deep into a rock formation at a carefully selected and safe site, where it is permanently stored.
Carbon dioxide is routinely separated and captured as a by-product from industrial processes, meaning that the technology for the capture side of the CCS equation is well developed - if expensive.
It is surprising, then, that the pace of deployment has been so slow. In 2019, 29.9 million tonnes of CO2 was captured. Projects already under construction should capture another 10 million tonnes. These numbers need to be viewed in the context of the International Energy Agency's 2019 World Energy Outlook which estimates that for a two thirds chance of limiting warming to 1.8C we need an average of 1.5 billion tonnes per annum of CO2 capture and permanently storage each year until 2050 - starting now.
To speed up CCS deployment we urgently need significant cost reductions; a price on carbon emissions (providing and incentive to store carbon); or regulations which mandate a maximum carbon content for every unit of production. Improving the efficiency of capture is also important - both from a cost and a CO2 avoidance perspective; innovation is ongoing.
One way in which the industry has sought to monetise the carbon captured is by using it for enhanced hydrocarbon recovery. In enhanced oil recovery(EOR) CO2 (or CO2 plus water) is injected into depleted oil fields to extract oil which would otherwise not have been recovered.
From a carbon perspective this is a slightly baffling idea. Captured carbon is used to access a further source of carbon. Only under very stringent capture and storage conditions is any carbon benefit forthcoming. Moreover, most of the CO2 currently used for EUR is taken from underground deposits rather than being captured (from industrial sources or direct air), so further increasing emissions.
Other potential uses for captured carbon include turning it into carbon fibre (a lightweight, high strength material with many uses) and using it in the concrete industry. If these can be profitable, that obviously reduces the overall cost premium for adding CCS.