Carbon dioxide would be the perfect criminal. The stealthy greenhouse gas is invisible, expensive to catch, and hard to lock up. That’s a big problem for any power company, future carbon regulator or taxman.
One way of dealing with it involves trapping the gas in large cavities a mile beneath the surface. No supermax prison could match this hell. Such carbon sinks are twice as hot as boiling water and the air pressure feels like swimming four miles below the surface of the sea, double the depth of the Titanic wreck. But could the gas still wiggle out of this trap?
Counting Bubbles: New GE sensors will take stock of massive underground carbon sinks.
Bill Challener, a physicist and principal investigator in the Photonics Lab at GE Global Research, is trying to find out. He and his team of scientists are building high-pressure sensors that can handle as much as 600 degrees of Fahrenheit. The sensors have already been used to measure the pressure inside deep geothermal wells with minute accuracy. A drop in pressure signals gas leakage. “The idea is that if we store CO2, it has to stay there,” Challener says. “Temperature and pressure are key factors to understanding what’s happening deep underground.”
The team plans to string the sensors along a glass fiberoptic cable “like raindrops on a silk spider thread,” Challener says. His team is using glass rather than silicon because silicon electronics would fail in the heat. The first generation prototypes of the sensors are over an inch large but the team is already thinking of ways to shrink them, adding wireless controls, and combining the heat and pressure gauges in a single unit. The scientists will be also building customized chambers to test the devices. “We want these things to last for 20 years,” Challener says.
GE Global Research has contracted with the National Energy Technology Laboratory on the $1.2 million project.