Carbon Dioxide Capture Technology

(Artists rendering of a carbon capture tower)

For the past 14 weeks I have been collecting information about carbon capture technology, following recent developments (and past) to try and give the most detailed report I can about its current state and its reliability of it being a viable way to help combat the amount of CO2 we have in the atmosphere.

Carbon Capture Technology. (sometimes know as CCS or CCT).

Recently; due to global shifts in attitude, and climate, global warming has become a major issue within all aspects of life. With the ever growing amount of carbon fossil fuels being used up increases the damage that they are causing to the planet increases with them. With LEDC countries producing more pollutants due to lack of technical maturity, and their increasing rate of growth is a rising cause for concern. It has brought rise to the concept, and application of many new technologies to attempt and solve, or counter the amount of carbon dioxide that is being produced currently in the world.

For many years now the concept of carbon capture technology has been just that, a concept. Recently however this has become more of a reality and especially with the recent developments over the past few years.

Objective of Carbon Capture Technology.

As no one company owns “Carbon capture technology” it is very hard to say what its overall aim is, as some companies have different views on this so a singular answer is hard to come by. However the main aim behind it (at a fundamental level), is to capture, and store the excess carbon that is the result of combustion of fossil fuels, such as coal and gas. The technology is being used to actually removed the CO2 from the air itself, which is a great success to the application of this technology, for it allows the capture devices to be placed in such areas that are not near the main cause of the emissions, such that it can still be extracted from the air without having to be near the point of emission.

(Diagram to show the proposed methods of storing and collecting the CO2 - http://www.greenhouse.gov.au/ccs/publications/key-findings.html)
Currently, Carbon capture technology is still undergoing development in some areas. Capture at the point of release for the emissions is well underway and pretty well understood, whereas capture from the air itself is only just being devised (see below in ) and implemented. However the big problem of the energy cost of this method has still not really been resolved, for instance such as the increase at PowerStation’s.

There are many ways that carbon capture technology is being used, working or being developed. The most common (also the one that is being trialed and used now) is in power stations, where the flue gasses (the emissions from the station) are “scrubbed” and the majority of the CO2 is removed from them, resulting in an almost pure emission. This is sometimes known as Oxyfuel combustion.

In “Oxyfuel” combustion referred to as "zero emission", pure oxygen is burned instead of air. This produces a flue gas consisting only carbon dioxide and water vapor, which is cooled and condensed. The result is an almost pure carbon dioxide stream that can be transported to the sequestration site and stored. The technique is promising, but the initial air separation steps demands a lot of energy. Post-combustion, the CO2 is removed after combustion of the fuel - this is the scheme that is active in current power plants. Carbon dioxide is then captured from flue gases (in the example of coal, it is sometimes known as "clean coal"). The technology is well understood and is currently used in places such as Didcot power station. The main cost for the post combustion is from the excess energy required to run the plant, an extra %10-%40 is estimated, with a %30-%60 increase in other area’s dependant upon the circumstances of the plant

Storage – Commonly known as geo-sequestration this involves injecting the collected gas into underground Oil fields, gas fields, saline formations, unminable coal seams, and saline-filled basalt formations have been suggested as storage sites. Here, various physical (e.g., highly impermeable caprock) and geochemical trapping mechanisms would prevent the CO2 from escaping to the surface.
Another proposed method of storage is in the oceans. Two main ideas circulate, the dissolution type involves injecting CO2 by boat or pipeline into the water at depths of 1000 m or more, and the CO2 then dissolves.
The lake type deposits CO2 directly onto the sea floor at depths greater than 3000 m, where CO2 is denser than water and is expected to form a lake that would decrease release of CO2 into the environment.
The time it takes water in the deeper oceans to circulate to the surface has been estimated to be on the order of 1600 years, varying upon currents and other changing conditions. Costs for deep ocean disposal of liquid CO2 are estimated at 40-80USD/ton. (2002 USD)

(Diagram showing how much CO2 could be prevented from escaping into the atmosphere where CCS is apparent.)

Status of The Technology
Three industrial scale geological storage projects are currently in operation:
• The Sleipner project operated by Statoil in the North Sea about 250 km off the coast of Norway. The project injects approximately 1 million tonnes of carbon dioxide (CO2) each year, sourced from a gas field, into a deep, saline reservoir 800 m below the sea bed. Injection began in October 1996 and, by early 2005, more than 7 million tonnes of CO2 had been successfully stored. The project involves an extensive monitoring component, and results indicate that no CO2 has leaked from the reservoir.
• The Weyburn project in Canada is an enhanced oil recovery project where CO2 is injected into an oil reservoir in order to boost oil production from the reservoir. The project injects approximately 1,000 tonnes of CO2 each day and aims to store the CO2 permanently. Injection began in late 2000, and extensive monitoring indicates there has been no CO2 leakage to the surface and near surface environment.
• The In Salah project is a joint venture operated by Sonatrach, BP and Statoil, and is located in the central Saharan region of Algeria. The project involves re-injecting CO2 sourced from a gas field into a sandstone reservoir at a depth of 1,800 meters and storing up to 1.2 million tonnes of CO2 each year. Injection began in April 2004 and extensive monitoring is planned.
Components of carbon dioxide capture and storage are in various stages of development. For example:
• capture technologies range from demonstration phase to economically feasible under specific conditions
• mineral carbonation is in the research phase
• Enhanced oil recovery is in the mature market or commercial phase.
Alternatives to Carbon Capture.
Alternatively, the use of nano technology, rather than the pred-escribed methods, could have a much better alternative to the method of capture. Using a membrane on nano wires. This new type of membrane has been internationally patented by researchers at The Norwegian University of Science and Technology (NTNU) in Trondheim. The membrane is made from a plastic material that has been structured by means of nano technology. It catches CO2 while other waste gases pass freely. This is very useful when considering the ways this could be implemented, capture devices, in exhausts etc
This new method is made from a eco friendly materials, which would help to further reduce the heavy costs of carbon dioxide capture.
Other Alternatives include such things as geothermal technology, harnessing the heat of the earth and converting that heat energy into other useable forms, notably electrical energy. The most popular areas for this kind of technology are areas with high geo-thermal activity, Iceland and Greenland for their numerous amounts of hot springs and geysers are just 2 of the many locations where this technology is and can be utilized.
Potential Political and Financial Effects of CCS/CCT.
The biggest financial effect of the proposed technology would be the increase in costs of both storage, and extraction / filtration or any other method by which the CO2 is captured and then stored. This is because of the basic fact that the capture method requires additional structures, transport, management and funding than a normal power plant or structure would need. This also therefore has a big impact on the implementation of the technology, as companies now-a days are mostly about the profit rather than anything else, and who would want to spend more money than they really have to?
However the political effects could become a lot more complicated. Where would the storage sites be located? Some countries would object to having them or exploit the capability to store it, such as oil rich countries, or ex-oil rich countries where the now void spaces would become very useful storage sites for the gas. For instance one country could hold the rest of the currently usable space and therefore exploit it by raising the price to store it in their country and thusly gaining more from it. This would therefore need to be resolved by some sort of council (possibly then UN) to come up with some kind of resolution that would allow the allocation of the CO2 responsibly. Also there are very few regulations for pumping or injecting chemicals into the oceans, which again would also have to be re-examined for the technology to go wide scale as incorrect injection could result in leaks and therefore destruction of ecosystems and wildlife.
Also the fact that many of the worlds oil producing countries, happen to be less developed than the oil consuming countries, this leaves a problem with the storage of the gas too. The technology would not be as mature in these countries as they would in the more developed, and thusly regulations would have to be a lot tighter, equipment would have to be imported or directly funded from the richer nations, to help lower the chance of mistakes or poorly injected chemicals – as what good would it do to have a leaking storage due to the fault of poor equipment, the problem wouldn’t not be solved only worsened.
Global and International Effects.
If the technology is allowed to progress like it has done so far, I see it becoming one of the biggest ways in which we can combat the high levels of CO2 ¬ that is currently plaguing the planet.
Globally this technology has the potential to help accommodate the dependency we have currently on fossil fuels, so while the twilight period from the transition of fossil fuels to the next-generation of fuel’s is commencing, this technology will be around to help and reduce the effects that we are having currently on the planet.
Conclusion
Conclusively I think that this technology, like I mentioned before is one of the best resolutions to the growing CO2 problem that we are having in the world, it does not resolve the problem entirely yet it does help to reduce the problem, and with the ability to store the gas for thousands of years, if not even longer which allows the world over to help try and solve the problem of global warming. However in saying this the solution is not final, as the gas escapes even in small quantities and from the diagram above, even having the technology, some of the gas does escape from the capture method, which ends up in the atmosphere, the only way I see it working, would be to have a balance of source capture, with a capturing of the gas at other areas to help ensure a world wide coverage.

http://www.greenhouse.gov.au/ccs/publications/key-findings.html