One of many approaches to combating climate change is “Carbon Capture and Geologic Sequestration” (CCS). It’s a pretty straightforward idea: capture climate-change-causing carbon emissions and lock them up underground, rather than letting them float up into the atmosphere where they would contribute to global warming.
The concept may be simple, but the actual engineering of it is as complicated as you might guess. The first problem is capturing and transporting CO2 emissions to their “resting place.” And then comes the second, injecting the CO2 into a deep geologic formations that will trap it underground for hundreds to thousands of years. Suitable homes for such captured CO2 include oil and gas fields (they’re already drilling deep down anyway), saline aquifers, and deep coal seams.
As it happens, several CCS projects are underway in Norway, Algeria, and Canada and more are planned in the United States, China, Australia, and other European countries. In fact, four CCS projects are currently active, each injecting roughly 1 million metric tonnes of CO2 per year. Two projects involve injecting CO2 far below the seafloor into deep gas formations – the Sleipner natural gas field in the North Sea, about 250 kilometers off the coast of Norway; and the Snøhvit natural gas field in the Barents Sea. A third project in In Salah, Algeria, involves injecting captured CO2 into a land-locked deep gas formation. Finally, the Weyburn-Midale CO2 project in Saskatchewan, Canada, involves injecting CO2 into depleted oil fields in order to increase reservoir pressure and oil fluidity – the better to extract additional oil from the fields, while trapping the CO2 underground.