One technology, carbon capture and storage (CCS), stands tall for its ability to help energy-intensive sectors like power generation and heavy industry reduce their emissions. In fact, the International Energy Agency has said without CCS, achieving the world’s lower-emission targets will be virtually impossible. While the technology isn’t new, it is increasingly coming to the forefront of the climate conversation. But what is carbon capture and storage?
Carbon capture is the capture of CO2 emission and the storage is sequestering them underground. The process is highly energy intensive and probably has been overtaken by 'green' electricity generation which is much cheaper
CO2 emissions are rising globally in a nearly monotonic way. The only significant changes in emission rates have been associated with global economic downturns, with no evidence that they will peak any time soon. While everyone should support the development of rational renewables, they have not and probably cannot substantially replace fossil fuels in many industries. Carbon capture is essential to the success of any realistic climate mitigation technology. Also, the term carbon capture is nearly universal, but what it really means is carbon dioxide capture (separation of CO2 from other gases, most commonly in fossil energy exhaust streams). Storage is isolating this carbon in some location where it does not reenter the atmosphere either by converting it to useful, non-volatile products or by sequestering it in geologic storage locations such as sealed, underground aquifers. The current emission rates of CO2 exceed the sum of non-fuel use of carbon by very large margins, so while CO2 conversion to products in rational ways has many advantages, it is hard to see how such activities could contribute at the same level as sequestration.
Full disclosure here that we have developed a much cheaper and energy efficient process (Cryogenic Carbon Capture(TM)), though this response is not specific to that or any other technology.
Oxyfuel combustion capture is the most efficient carbon capture technology, with the ability to capture 100% of carbon emissions. The efficiency comes with a price, however. Oxyfuel capture is the most expensive method of carbon capture and is very energy-intensive.
For more information, please read the "New Carbon Capture Technology: A Ray of Hope" paper by Eric Koons.
- Cryogenic capture can capture CO2 with > 100 % efficiency (captures all of the CO2 produced by a process and part of the CO2 that enters the process as part of the air). This is a form of direct air capture that leverages both existing industrial equipment for gas handling and the carbon capture capital investments made for the process. The energy demand and cost per tonne CO2 captured increase as the capture % increases, but only modestly in the case of cryogenic carbon capture and the direct-air-capture version of cryogenic carbon capture has a marginal cost of CO2 capture in the 100% efficiency region several times lower than dedicated direct air capture. Costs for traditional capture are much lower than for amines. See DOI:10.2139/ssrn.3819906, 10.2139/ssrn.3820158, and 10.2139/ssrn.3820158 for brief discussions.
The science of CCS is quite simple; the engineering has so far proved less simple. The only successful schemes so far have been in secondary oil recovery and are relatively small. The quandary for developers is that the energy required to trap and store CO2 is enormous and the world needs to increase energy usage to improve human development. Growing a lot more trees and increasing wood usage are the only effective cost / benefit CCS methods so far as I can see.