ANY combustion-based generating source will emit Carbon Dioxide - the scrubbers just remove the pollutants that have been identified as causing acid rain. It may incrementally reduce the amount of carbon but I've never seen any studies that indicate that scrubbers remove significant amounts of carbon from the stack emissions. That's not what they're designed to do and I'm guessing any reduction would be incidental to their primary purpose.
Here's a pretty good study on carbon emissions from various generating sources from Lawrence Livermore Labs:
The only generating sources that do not increase carbon loading are the renewable resources such as hydropower, wind, geothermal and solar. Biomass, although renewable, also has a pretty heavy carbon footpring. Nuclear is also a huge generating source that's carbon neutral which explains the renewed interest in new nuke plants lately.
Watch the new interest in ocean energy projects that has exploded since EPRI issued their nationwide assessment of the potential of these resources last year. I believe there are have been over 70 preliminary permits filed with the FERC to explore development of these tidal and wave projects along the coasts. Eliminates the need for dams but still running into serious environmental resistance from Federal and state agencies. Many of the major utilities are looking at these potential projects now but I don't believe that Duke is pursuing any and is instead moving towards clean coal and nuclear generation instead.
Also a recent resurging interest in new pumped storage projects that fit nicely with fossil fired units and allow them to operate more cleanly and cost effectively by storing energy from these base load plants at night when demand drops off.
Now if you want to argue whether the carbon loading from these plants is responsible for the current global warming trend that's certainly debatable and a very complex question. There's no traction in trying to argue that scrubbers remove CO2 from the stacks though.
Whatever company figures out how to do that will be a good one to invest in ASAP.