Supercritical carbon dioxide is used to enhance oil recovery in mature oil fields. At the same time, there is the possibility of using "clean coal technology" to combine enhanced recovery methods with carbon sequestration. The CO is separated from other flue gases, compressed to the supercritical state, and injected into geological storage, possibly into existing oil fields to improve yields.
At present, only schemes isolating fossil CO from natural gas actually use carbon storage, (e.g., Sleipner gas field),  but there are many plans for future CCS schemes involving pre- or post- combustion CO. There is also the possibility to reduce the amount of CO in the atmosphere by using biomass to generate power and sequestering the CO produced.