By Teri Walker–
With concern over emissions from coal-fired power plants a mainstay in environmental discussions, the possibility for stricter emission standards is never far from the minds of plant operators.
Which is why the coal industry continues to explore options for dealing with carbon dioxide (CO2) in a manner that will reduce environmental impacts and satisfy regulators.
In 2009, the West Coast Regional Carbon Sequestration Partnership (WESTCARB), based in Oakland, Calif., conducted testing in the Holbrook area, expanding research in the field of capturing and storing carbon dioxide in wells drilled in secure geologic formations.
WESTCARB is a collaborative research project formed in 2003 to study how to keep CO2 out of the atmosphere. The partnership includes scientists and engineers from more than 90 public agencies, private companies and nonprofit organizations. It is co-funded by the U.S. Department of Energy and the California Energy Commission, which manages the program.
Based on extensive mapping and research available on wells and geologic formations in the Colorado Plateau of northeastern Arizona, WESTCARB participants believe there are suitable geologic conditions in the region for safe long-term CO2 storage.
The partnership’s pilot project in Arizona was located near Cholla Power Plant, operated by Arizona Public Service Co. (APS), outside of Joseph City.
WESTCARB drilled a well in an area with desirable geologic formations, but found insufficient permeability in the rock formation, which nullified plans for carbon capture at that location.
Still, WESTCARB has not abandoned the idea of capturing CO2 emissions in northeastern Arizona.
“Although our Cholla well did not find sufficient permeability in the target geologic formation to support a potential future commercial CO2 storage project at that location, we believe that result was a local anomaly. Drilling additional deep wells in northeast Arizona would provide communities and businesses with a clearer regional picture of the CO2 storage capability of deep sandstone and carbonate strata overlain by sealing caprocks (a prevalent geologic structure),” said Rich Myhre, outreach coordinator for WESTCARB.
Myhre said WESTCARB is considering alternate well sites to the north and east of Holbrook. Specific well sites have not yet been determined, with Myhre explaining there is ongoing geologic screening by Errol L. Montgomery & Associates, an Arizona geologic/hydrologic consulting firm. Other determinants for well location include the level of funding by DOE and WESTCARB’s industry partners, along with the interest of the site landowner and neighboring communities.
Myhre explained that nature has been storing CO2 and other substances like oil and natural gas in underground geologic formations for millions of years. Now, these formations are being explored for storage from industrial sources.
WESTCARB sees the saline formations, layers of porous rock that are filled with saltwater, as the largest CO2 storage opportunity nationally and in the West Coast region. Three major CO2 injections into saline formations for storage are ongoing in Norway and Algeria, and results from these projects show that saline formations can serve as reliable, long-term CO2 storage sites. Through projects in seven western states (including Arizona) and British Colombia, WESTCARB is determining whether the same storage results can be achieved in the western region, and whether they can be managed cost-effectively for industry.
“The value to the community of knowing whether the area could support commercial CO2 storage projects remains as important as ever,” said Myhre. “In the event that power plant CO2 emissions were to be regulated in the future, knowledge of the viability and cost of deep saline formation storage beneath the Colorado Plateau would help power plant owners and the communities of the area make informed compliance decisions in a manner that maximized economic benefit and preserved cherished ways of life.”
Myhre could not say if or when other well sites would be drilled in northeastern Arizona, but did note that there is still great interest on the part of WESTCARB and its industry partners, including Salt River Project (SRP) and Tucson Electric Power, in moving forward. He said APS is less interested in participating in the next project phase because WESTCARB is not considering additional wells near Cholla Power Plant at this time.