This is the process where Co2 emissions are captured at some point in a combustion cycle and, by one of a variety of means, are trapped and sequestered so they do not enter the atmosphere.
This is seen by many as, at worst, nothing but a trick dreamed up by the oil companies to facilitate even greater profits while postponing the inevitable, that is, the day we wean ourselves from carbon fuels altogether. Others view CCS as a stopgap type of measure, which could be quick to implement and relatively useful until such time as alternative energy production is brought up to speed. And, there are others who see this option as the holy grail of making our energy needs compatible with the healthy future of the planet. Which is it? I dunno but let's take a look.
There are many different variations of CCS. Probably the most common is where Co2 is captured in a coal burning or other combustion process and then pressurized, liquefied and injected into the earth. The most common injection sites used so far are old oil fields, where the liquid Co2 is effective for recovering additional oil that otherwise wouldn't have been possible to get out of the old wells.
Then there are many variations of this process ranging from different ways of preparing the underground site to ocean floor scenarios, etc.
The other most promising technique, rather than liquifying the Co2, is to use a process called carbon mineralization, where the Co2 is used to form carbonate solid material, such as limestone or other rock.
CCS is well established on a small scale. One of the largest facilities in the world is the Petroleum Technology Research Center in Weyburn, Saskatchewan. Once full, this facility will contain the equivalent of the Co2 produced by 6 million cars in one year.
The government of Alberta has budgeted $2 billion for CCS and several projects have already started.
The problems with CCS at a glance are as follows:
* high cost of capturing the Co2 (approx 20-25% of energy produced)
* high cost of liquefaction
* cost of transport
* potential of leakage
* the solution is not permanent
* sequestration sites are finite
CCS drives petroleum consumption
So, the total cost in energy and dollars of the CCS process would be something like 50% of the energy produced in the original process.
Add to this consideration the fact that oil from the tar sands already implies a huge energy component in initial production.
Well, the good thing about all this for the oil companies is that the additional energy they use can be seen as additional sales for their industry, which also have the effect of supporting petroleum prices and so forth.
The other problem is that this method only deals with the Co2. Many other serious pollutants are still dispersed into the atmosphere.
This problem is also present with the carbon mineralization technique. However, there are some advantages. First of all, the by-products of carbon mineralization, whether they be limestone or a similar carbonate, are all inert, non-toxic, solid materials that can be buried, piled or used for pretty much anything. Secondly, this technique is permanent - and, for the sake of discussion, sustainable.
In the case of carbon mineralization, you still have to capture the Co2, so you still have that cost. Most of the other costs are as yet undetermined.
Company claims to produce fuel from Co2
The down side of this technology is that tried and proven methods of rapid carbon mineralization are still in the research stage. Much of the information out there is locked down in academic portals that you have to subscribe to or pay as you go. In short, C-M could have potential, but working models are still few and far between.
There are many other techniques out there.
There has been a proposal floated for such a thing as zero-emission coal, a complex process that seems to lead to either CCS or carbon mineralization in the end anyway.
Beyond that, there is even a company in California, Carbon Sciences Inc., that is claiming to be able to produce fuel from Co2, effectively recycling the emissions.