Greentech Lead America: GE Global Research has signed a contract with the
National Energy Technology Laboratory (NETL), part of the U.S. Department of
Energy (DOE) national laboratory system, to build a multi-point sensing system
to monitor carbon dioxide (CO2) injected into geothermal containment wells.
The use of these cavities, which extend 1-2 kilometers
below the surface of the Earth, is being explored by the federal government and
power producers as an option for the long-term storage of CO2.
GE multi-point sensors would enable continuous monitoring
of pressure and temperature inside wells to detect potential leaks sooner.
Carbon dioxide emitted from the combustion of fossil
fuels represents 84 percent of U.S. greenhouse gases, according to a 2010
analysis by the U.S. Environmental Protection Agency. Carbon capture and
sequestration of highly pressurized CO2 in underground wells is viewed as
a promising alternative to the release of CO2 gas into the atmosphere.
Highly accurate monitoring, verification, and accounting
are critically important to ensure that CO2pumped underground is confined to
the potentially porous or fractured rock that contains each well. New GE
CO2 sensor technology could help foster widespread adoption of carbon
sequestration as an environmentally-friendly alternative, the company said.
GE is testing a fiber optic cable with a sensor that can
measure temperature and pressure at a single point inside the well. Readings
from that pressure sensor have been calibrated to an accuracy of Â±0.1 percent.
This follow-up project would add a yet-to-be-determined number of additional
sensors along the length of a multi-kilometer cable, enabling engineers to
track the disbursement and movement of CO2 within the sequestration well
with even greater precision.
“Our goal is to develop an incredibly resilient cable and
sensor system that can withstand an extremely harsh environment for an extended
period of time – temperatures as hot as 250Â°C and pressures topping 10,000
psi,” said William Challener, principal investigator and physicist in the
Photonics Lab at GE Global Research.
“We have already developed a single sensor system that
can tolerate temperatures as high as 374Â°C and 3,000 psi for short periods,”
Challener added. “Now, we’ll leverage that knowledge to build a package that is
even more robust and that can be multiplexed along the cable.”
Another key component of the project is wireless
communication. GE scientists will develop a remote monitoring system capable of
activating and operating the sensors from an off-site control room.
“The end-goal is to ensure confidence in the long term
stability of CO2 sequestration sites,” said Challener. “We believe the
fiber optic cable and sensing system we’re tasked with fabricating will help
make that goal a reality.”
Work on the two-year, $1.2MM joint venture between GE
Global Research and NETL is slated to get underway in January, 2013.