Carbon sequestration, also known as carbon capture and storage (CCS), is a technological approach to solving global warming by preventing the CO2 from entering the atmosphere when coal is burned. The process involves capturing CO2 at coal-fired power plants, transporting the gas, and storing it instead of letting it enter the atmosphere.
However, it is extremely expensive – not nearly cost-competitive with other solutions to the climate crisis. There are also major concerns over CO2 leakage and the fact that the sequestration process itself requires large amounts of energy. Additionally, the technologies needed for the process are not likely to be ready in time to apply CCS to new power plants about to come online, and retrofitting old plants with CCS is very expensive. Since now is the time to cut emissions, carbon sequestration is not the answer. Read the Intergovernmental Panel on Climate Change Report on CCS for more detail.
- CCS technologies could capture 85-95% of a power plant’s emissions, but do not address toxic waste or other air pollutants such as mercury.
- The three types of CCS technology that have been demonstrated to work in certain conditions are pre-combustion, post-combustion, and oxyfuel combustion.
- Methods of ambient air capture are also proposed for controlling emissions. This process of removing CO2 directly from the air would address emissions from automobiles, but would be very costly and remain an unproven technology.
- For distances up to 1,000 km, pipelines are used to transport the compressed CO2. For longer distances or locations inaccessible by pipeline, ships or trucks are used.
- CO2 is released in the process of transporting captured CO2 for storage, as the trucks and ships burn fuel.
- CO2 can be stored in underground geological formations, the ocean, or mineral carbonates. In some cases, it can also be used for industrial purposes.
- Geological storage options include gas or oil formations, saline formations, Enhanced Oil Recovery (EOR), and Enhanced Coal Bed Methane recovery (ECBM).
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