This has been suggested before. Scale is still hard. I read an article in the UC Davis algae magazine (http://www.algaeindustrymagazine.com/department/education/we...) a while ago that talked about flooding a fairly large acre (hectare) parcel with water, growing a layer of algae on it, then burying the algae. (process flood, algae mat grows, drain/evaporate, and plow it all under, then repeat.) The algae decomposition process releases methane (worse than CO2).
only if we cannot capture methane. If we can capture it, we can run it through an engine and get the energy back. Most landfills are already doing this: it adds some extra profit to the bottom line.
I have no idea if this stores any carbon anymore though.
