Industrial-scale carbon sequestration is in the news again: an MIT report (and here) says the coal industry is way behind in getting sequestration off the ground. A lot of people (including my second link) see sequestration as absolutely crucial to our future energy system. (See wikipedia for a good introduction to sequestration, and ignore the stuff about biological sequestration for now.)
As I'm sure you'll be surprised to know, I'm not so sure. (And I'm important! I have the blog to prove it!) Sequestration is a tricky thing--ocean sequestration may be a new form of pollution, while underground sequestration may be risky due to, you know, earthquakes. One thing I'm fairly confident on, though, is that sequestration doesn't need subsidies. The fossil fuel industry is fully mature, and it got that way through a century or more of public support and subsidy. It can afford to look after itself, if it wants its product to make the transition to a future de-carboned world. Public money is scarce, though, and so it ought to go to support technologies that we know can work, like improved efficiency, solar, and wind.
I know some people will croak at the thought of solar and wind being proven technologies, but to my mind the only thing holding them back is battery capacity. And building a better battery--or, at any rate, a lot more batteries--seems like more a sure thing than tucking a gas into gaps in the deep ground, such that it won't escape. And, of course, wind and solar (not to mention my pet favorite, geothermal, and not to mention the really new kids on the block like tidal power) are still comparably new. Subsidies can help mature these industries that can become the core of the our energy the easiest. Moreover, anyone can get in on solar and wind and all the rest at this point--someone as little as CWLP has the potential (in my mind) to be a major driver of geothermal, for instance. Not so for coal: subsidies there are going to go to one of a few well-established massive energy companies.