A new article from Scientific American suggests putting up a link to the 2011 study by the American Physical Society on the topic would be a good idea. Note that while some costs are estimated, and compared to costs of capturing CO2 right out of the flue of a plant generating, say, electricity from a fossil fuel, in the words of the report “It was beyond the scope of this report to investigate post-capture management of CO2 in any detail”, including the associated costs.
The comparison with costs to capture out of the flue are interesting for an additional reason: They indirectly show how much more such capture would cost compared to simply not burning fossil fuels. After all, the primary costs of using non-carbon kinds of energy are not costs of operation, but, rather, costs of (a) capitalization to erect enough carbon-free energy to replace a fixed based of carbon-derived energy, and (b) loss of assets committed to production of energy using fossil fuels, appropriately depreciated, and including indirect assets such as pipelines. To the degree existing fossil fuel energy sources are built and being built at a rate of capital consumption, and to the degree the feeding of these with fossil fuels is a cost of operation, in principle that should be able to be stopped and all that devoted to the building and production of carbon-free energy.
According to 2013 figures from the Energy Information Administration, onshore wind is about the same cost to construct as is a coal plant, per KiloWatt, and has the same cost of operation and maintenance. That cost is approximately twice that of a natural gas plant, and operating costs for natural gas are also about half of that for coal or wind. The same figures show offshore wind has construction capital requirements three times that of onshore (and also coal) and operating costs about twice those of onshore. (Think about that the next time you want to vote down turbines in your town.) Large scale solar photovoltaic power is slightly more expensive to build, per KiloWatt than onshore wind (and coal) but operates at costs only 50% higher than natural gas. Adding carbon dioxide capture out of the flue doubles the cost of both coal and natural gas energy. Yet that is only one-eighth of the the cost of clear air capture, according to the APS report, and they haven’t added in the costs of managing it1.
Of course, capturing out of the flue does nothing to solve the problem of greenhouse gases emitted upstream during production and delivery, before the fossil fuel reaches its point of use.
In short, the cost of removing CO2 from atmosphere after emission when its effects become intolerable completely dwarfs the costs of operating and building carbon-free energy sources.
1 The APS report did assume some value would be obtained from the captured CO2, although they did not consider management costs, as mentioned. Without recovery of value from the captured CO2, the costs of clear air capture are thirty times larger than those of capture at the stack.