GE Global Research has signed a contract with the National Energy Technology Laboratory, part of the US Department of Energy national laboratory system, to build a multi-point sensing system to monitor carbon dioxide injected into geothermal containment wells.
The use of these cavities, which extend one to two 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.
Carbon dioxide emitted from the combustion of fossil fuels has long been an environmental concern. It represents 84 percent of US greenhouse gases, according to a 2010 analysis by the EPA. The government views carbon capture and sequestration of highly pressurized CO2 in underground wells as a promising alternative to the release of CO2 gas into the atmosphere.
Accurate monitoring, verification, and accounting are critically important to ensure that CO2 pumped underground is confined to the potentially porous or fractured rock that contains each well. Currently, 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 a margin of error of 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.
GE says its 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 482°F and pressures topping 10,000 psi. The company has already developed a single sensor system that can tolerate temperatures as high as 705°F and 3,000 psi for short periods.
Work on the two-year, $1.2 million joint venture between GE Global Research and NETL is slated to get underway in January, 2013.
Carbon sequestration offers the best hope for mitigating the climate impacts of raising beef cattle, according to a report by the Union of Concerned Scientists released in February 2011. The said that US crop and grazing land could sequester about 15 percent of global warming emissions from the nation’s agriculture each year.