Scientists and companies are at a raise for finding carbon capture technologies that are less expensive and more sustainable.
There is a large project in Saskatchewan, Canada called Boundary Dam that is capturing CO2 from a coal-fired power plant at a rate of approximately 3,000 tons of CO2 per day.
There are large-scale CCS projects in operation or in construction capturing more than 30 million tonnes of CO2 per annum. Here are just a few of them:
Canadian governments have committed $1.8 billion for the sake of funding different CCS projects over the span of the last decade. The German industrial area of Schwarze Pumpe, about 4 kilometers (2.5 mi) south of the city of Spremberg, is home to the world’s first demonstration of carbon capture technology coal plant, the Schwarze Pumpe power station.
In Norway, the CO2 Technology Centre (TCM) includes two capture technology plants both capturing fluegas from two sources, a gas-fired power plant and refinery cracker fluegas. The Illinois Industrial Carbon Capture and Storage project is one of five currently operational facilities dedicated to geological CO2 storage.
What is the Potential for Carbon Capture?
This technique cannot solve the problem of climate change by itself but what it can do is (a) reduce the global cost of tackling climate change effectively and (b) allow the world to continue using its established energy infrastructure without too great a disruption.
The potential for carbon capture is limited by a number of factors:
(a) there is only so much storage capacity underground (no one knows the full extent but it is very unlikely there is anything like near enough to allow the world to continue burning fossil fuels at the rate that we are doing at present).
(b) the capital cost of the plant dissuades early-stage investment (the plant has to be large scale otherwise it makes no sense to use it, so demonstrations of feasibility have to be done at a large scale too); even governments are reluctant to fund demonstrations at sufficient scale.
(c) the capture process uses energy and so reduces the overall thermal efficiency of the power plant or whatever source of carbon dioxide is being addressed – this is something that can and is being tackled by R&D.
(d) the technique is used only for large, stationary sources of carbon dioxide, so small and especially mobile sources are not immediately addressable – these account for a substantial part of carbon dioxide emissions worldwide – the answer to this problem is to change the energy carrier, i.e. use electricity or hydrogen for fuelling cars and heating buildings instead of fossil fuels, since both of those carriers can be made from fossil fuels using carbon capture.
The technique can also be used for capturing carbon dioxide from the combustion of biomass, which potentially provides a means of removing carbon dioxide from the atmosphere.
Carbon capture approach that holds out much promise is called soil carbon capture. It might be able to capture around 12% of the excess CO2 in the atmosphere.
Restoring ecosystem function to cropland uses biological symbiosis to capture and store carbon in the soil. The only downside to this would be quickly teaching enough farmers how to do it, then convincing them how important it is. It takes a very very very large amount of land using these new methods to make any difference.
Threes are much slower growing and there is not enough land available to successfully grow enough trees. Not to mention forest fires can reverse all that hard work in a single flash.
Carbon capture added to power plants using coal or gas are expensive and reduces efficiency. So in these other cases, it is usually more efficient and cheaper to just use hydroelectric, wind, and solar.
About two-thirds of the total cost of CCS is attributed to capture, making it limit the wide-scale deployment of CCS technologies. Optimizing a CO2 capture process would significantly increase the feasibility of CCS since the transport and storage steps of CCS are rather mature technologies.
An alternate method under development is chemical looping combustion (CLC). Chemical looping uses a metal oxide as a solid oxygen carrier. Metal oxide particles react with a solid, liquid or gaseous fuel in a fluidized bed combustor, producing solid metal particles and a mixture of carbon dioxide and water vapor. The water vapor is condensed, leaving pure carbon dioxide, which can then be sequestered.
CCS can be a limited tool in our fight against climate change. There are major changes that need to happen:
- Reduce fossil fuel use by replacing energy needs with as many feasible renewables as current technology allows.
- Change Agricultural methods to high-yielding regenerative models of production made possible by recent biological & agricultural science advancements.
- Large-scale ecosystem recovery projects are similar to the Loess Plateau project, National Parks like Yellowstone etc. where appropriate and applicable.
- Not all holes in the ground remain airtight. CO2 leaking out is just as bad as releasing it into the air in the first place.
- Burning a fossil fuel makes significantly more CO2 by volume than oil (somewhere on the order of 10,000 times as much).
- A lot of the oil wells are inconveniently located for CCS (say, at the bottom of the North Sea or the middle of the Arabian peninsula.)
