Microbes mine depleted oil wells

What to do with a depleted oil well? Turn it into a hydrogen factory.

Texan company Cemvita is promising clean hydrogen at less than US$1/kg, after testing a fascinating new technique in the lab and the field. The idea is to pump specially developed microbes into depleted oil wells, where they'll eat oil and excrete hydrogen.

So, it presumably stops up the top of the well, before pumping a heap of specially bred microbes down into its murky depths in a stream of recycled water. The microbes go to work, feasting, excreting and multiplying, and Cemvita captures the gases as they exit the top of the well, separating them into hydrogen for processing and sale, and carbon dioxide for sequestration. The company is able to send nutrients and inhibitors down into the well to keep things under control and moving in the right direction.