Not unlike algae fixation....
...which works on a small scale, but is difficult to scale and has a
very pricey upcharge for the power user. I have not seen a single
carbon sequestration method that doesn't have these downsides,
and while it is laudable to continue the search and have these
things on the shelf in case the price of fossil fuel energy
skyrockets, making these technologies economical, I really think
that low/no carbon solutions, including energy efficiency is a
much more palatable path to take. After all, keeping the coal in
the ground and using another energy source may prove to be the
cheapest carbon sequestration strategy out there.