Energy News: A Partner in the CarbonSAFE Rocky Mountains Project

By Mark Milligan

CarbonSAFE Rocky Mountains is a research and development project with the goal of planning and ultimately developing a system to effectively capture and safely store carbon dioxide (CO2) emitted from a coal-fired power plant in central Utah. The project is coordinated by the Energy & Geoscience Institute at the University of Utah in partnership with the Utah Geological Survey (UGS), Utah Department of Environmental Quality, Sandia National Laboratories, New Mexico Institute of Mining and Technology, Schlumberger Carbon Services, Los Alamos National Laboratory, and PacifiCorp. The UGS is leading all geological efforts for the project.

Temperature records show Utah’s climate is changing. Our snowpack melts earlier each year and heat waves are more common. Over the last century the state’s average annual temperature rose by about two degrees Fahrenheit (seasonal and annual average temperature data for all states can be found at Utah’s elevated temperatures are reflective of average worldwide temperature increases, which are chiefly attributed to elevated levels of greenhouse gases in the atmosphere, principally CO2. The harnessing of fossil fuels such as oil, natural gas, and coal built modern civilization, but in doing so transferred carbon that had been stored in underground geologic formations for millions to hundreds of millions of years into the atmosphere as CO2. Since the industrial revolution began in the 1700s, CO2 in the atmosphere has increased by approximately 40 percent to levels higher than any documented in the past 800,000 years of historical and ice core records.

For several reasons, Utah has started to reduce its reliance on coal-generated electricity. In particular, coal-fired power plants produce more CO2 per unit of electricity than other fossil fuels. A decade ago coal-fired power plants generated approximately 90 percent of the electricity Utahns used. Today that has fallen to approximately 75 percent. However, Utah is still a major coal-producing state with substantial reserves, and the state continues to depend on several large coal-fired power plants. Despite the continued reduction in reliance, coal power will not soon be entirely replaced.

An emerging technology, carbon capture and storage (CCS) holds the potential to reduce CO2 emissions from coal-fired plants, thereby bridging the gap until newer alternative forms of power generation are available. CCS is the separation and capture of CO2 from the exhaust gases of fossil fuel power plants or other industrial processes, and long-term storage of the CO2 in deep underground geologic formations (deep ocean storage is another potential option). This technology allows for continued power plant operation but with reduced CO2 emissions.

The process involves separating the CO2 from other exhaust gases, compressing it to a dense liquid state, piping it to an injection site, and injecting it through a deep well (at least 800 meters [2,600 feet]) into a suitable geologic reservoir for long-term storage. During and after injection the storage reservoir is continuously monitored to track CO2migration and any potential impacts such as induced seismic activity, while the overlying land surface and shallow subsurface is monitored for any signs of leakage. Conservative estimates indicate that geologic formations in Utah and the greater Rocky Mountain area can safely and permanently store many hundreds of millions of tons of CO2, enough for dozens of years of emissions from the many coal-fired power plants in the region.

The CarbonSAFE Rocky Mountains project is one of 16 projects across the nation funded by the U.S. Department of Energy’s (DOE) CarbonSAFE initiative. Past CCS projects funded by the DOE have focused on pilot or short-term injection tests. The CarbonSAFE initiative is designed to foster the development, permitting, and construction of long-term commercial-scale (50+ million metric tons of CO2) CCS systems targeted to be operational by the year 2025.

The CarbonSAFE Rocky Mountains project is in the initial phase of a potential four-phase, nine-year program with the goal of permitting and constructing a commercial-scale CCS system at PacifiCorp’s Hunter Plant, with the Huntington Plant as a secondary option. Phase I is an 18-month pre-feasibility study of technical and regulatory requirements. Multiple surface injection sites and deep-storage reservoirs are being evaluated with an emphasis on storage capacity, efficiency, and costs associated with CO2 capture, compression, transport, injection, and monitoring.

The UGS is leading the geological characterization of potential storage reservoirs and seals, such as the Navajo Sandstone and overlying Carmel Formation. The UGS has worked on CCS studies since 2003 as an original partner when the DOE established the Southwest Regional Partnership on Carbon Sequestration.

For more information on CCS work by the UGS, see the following:

Survey Notes, v. 49 no. 3, September 2017