Locking CO2 Away For Good

HobbySpacer writes: "The BBC reports that waste CO2 from methane extraction in the North Sea has been succesfully pumped back into the pourous sandstone beneath the ocean for the past 6 years without any signs of leaking. Carbon sequestration techniques like this are looking increasingly practical. CO2 is being pumped back into depleted oil fields, where it also helps extract remaining oil deposits, and into coalseams. The ocean is the biggest natural bank of CO2 but tests of ocean sequestration in Hawaii and Norway have been blocked by environmentalists who hate this kind of quick fix approach to the CO2 problem. But with developing countries like India and China certain to rely on their large coal reserves, sequestration may be the only realistic approach to reducing their CO2 output. An Economist article discusses currently available steam reformation technology that could allow a coal plant to output power and neatly separated CO2 and hydrogen. The non-polluting hydrogen is then available for cars with fuel cells while the CO2 is stuffed away."

Comments

CO2 future fuel...

[wiretrip]

Cool, maybe in about 2000000 years CO2 will become the next major fuel and everyone will be fighting over land 'rich in ancient CO2 deposits'!

What CO2 does in oil fields

[Spamalamadingdong]

Using CO2 to extract the oil better (by pressurizing depleted oil fields)

If I understand correctly, the CO2 provides a lot more than just pressurization (otherwise, water would be just as good and a lot cheaper). Liquid CO2 is a solvent, and can dissolve and transport oil which would otherwise remain stuck in the pores of rocks. It offers a way to recover oil from "tapped out" fields (where water has infiltrated between the remaining spots of oil and keeps them from being pushed save by density differences), and of course - if the CO2 is there under the ground, it isn't in the atmosphere and might even form carbonate rocks to lock it into place permanently.

I think that's the wrong problem scenario

[Spamalamadingdong]

What if something weird happens and the CO2 gets released in massive amounts?

That's rather unlikely, due to the depths we're talking about here, but... what if it doesn't get released?

The pH of the ocean is moderated by a carbonate/bicarbonate buffer. If you add acid to the ocean (including carbonic acid, H2CO3), some of the carbonate (CO3--) ions soak up hydrogen ions and become bicarbonate (HCO3-) ions. This is okay, but a lot of ocean organisms require carbonate ion to build their skeletons, including corals, molluscs, and a host of smaller things. Cut the fraction of carbonate in the ocean (and add acid, which tends to eat the carbonate they've already laid down) and they have a tough time surviving. The last thing we need at the moment is to put extra pressures on the surviving coral reefs, clam and oyster beds, and everything else out there.

Dumping CO2 where it changs the ocean chemistry may be a bad idea.