Now that you have captured CO2 from your process, what do you do with it?

When you come to a fork in the road, take it.

As industry rushes headlong into capturing CO2, it is imperative that we answer this key question. There is no shortage of debate over how best to prevent the captured CO2 from re- entering the atmosphere. Pause for a moment to take a quick (but deep) dive into the current status of disposition of CO2 after it has been captured.

At this time, enhanced oil recovery (EOR) is the primary route in the US to sequestering CO2. Injecting supercritical (high pressure) CO2 into depleted oil wells has been practiced for decades to force the remaining crude oil in the wells to the surface. This eventually produces refined gasoline and other products, the use of which results in more CO2 entering the atmosphere. In the EU, the injection of CO2 in the Sleipner West formation under the North Sea has been used for about 24 years to permanently sequester CO2 captured from this gas and condensate field. The natural gas in Sleipner contains about 9% CO2, which must be reduced before the gas can be commercially used.

Both these examples, however, have proven that permanent geological storage of CO2 is possible. And now a consortium of industrial giants are planning to develop a pipeline to inject CO2 captured in the future into geological storage deep under the US Gulf Coast.

While geological storage provides a mechanism for permanent sequestration, it is capital- intensive. This has led to a wide range of research efforts to transform captured CO2 into valuable products, ranging from ethylene (the most widely- produced chemical) and polyacrimides to fuels and synthetic fabrics. But these are just that--- research efforts--- and while promising, need time to fully develop.

Meanwhile, thanks to some innovative startups, techniques have been demonstrated to store captured CO2 in favorable rock formations, like basalt, which are present around the globe. The CO2 is converted in the basalt into carbonate minerals, resulting in permanent sequestration.

All this points to the potential for the deployment of numerous routes to the disposition of captured CO2, and why we should perhaps take ... that fork in the road.