Klaus Lackner and his associates have been working on a model to capture climate from the air rather than the smokestacks of coal fired power plants. That has many many advantages if it works and is cost effective:
1. Lots of CO2 comes from places other than coal fired power plants.
2. Capturing CO2 from them is going to be next to impossible.
3. To put it politely, not everyone running a coal fired power plant is necessarily going to actually capture the CO2 given the additional costs of doing so, even if they say they are going to.
4. Separating out who and where CO2 is produced and where and when it is captured allows the Developed World to clean up some of its historic output.
I spoke to Lackner recently, and he is cited figures of $200 a ton going down to $30 a ton for the operating such a system at scale. This includes the cost of manufacture and the power needs of the system but excludes the costs of sequestration. He envisages deploying small units (the size of shipping containers) that each remove 1 ton of CO2 a day. Like all carbon capture, this approach uses power, so unless you use renewable energy as a source, it adds to the problem as it works to solve it. Cleaning up the CO2 that a coal fired power plant produces requires you to burn 30% more coal to produce the energy for the clean up. On the other hand, with an ambient system you could locate Lackner’s units in a desert and run them with solar power. How many would you need? If each extracts 1 ton of CO2 a day, 3 will take out roughly 1,000 tons a year. The world currently puts out about 27 gigatons (billion tons) of CO2 annually and we need to reduce to 18 gigatons to stabilize atmospheric CO2 at 450 parts per million. Lackner is about to publish data on his work which has been eagerly awaited by the scientific community. If it holds up, the real fly in the ointment of the whole scheme may be the sequestration of the carbon. But one way or another, there is no getting around the urgent need to test sequestration for safety on land or in deep sea locations. There is too much coal available to burn.