An interactive atlas showing the vast potential for carbon capture was recently released by the U.S. Department of Energy (DOE), Natural Resources Canada (NRCan), and the Mexican Ministry of Energy (SENER). Carbon storage resources were “defined as the volume of porous and permeable sedimentary rocks available for CO2 storage and accessible to injected CO2 via drilled and completed wellbores.” As such, the atlas is an estimate of the geological and physical potential, but does not consider other challenges to implementing the technology, including land use and economic issues.
The atlas and website are really interesting for several reasons. The website gives good introductory information about carbon capture and storage (CCS) technology, types of geologic formations that could support carbon storage, a decent reference list, and links to several individual maps that comprise the interactive map. Using the interactive map, you can overlay the locations of stationary CO2 sources with different geologic formations for carbon storage (the only thing I don’t like is that stationary electric generating sources, i.e. power plants, are shown in a similar blue color to assessed saline storage sites). What really strikes you about the atlas is turning off and on the different categories of CO2 sources. Even from the overview map of stationary sources you can appreciate the prevalence and regional concentrations of power generation sources. From a look at the atlas, qualitatively it appears there are ample regional sites for carbon storage. Overall, an estimated 500 years(!) of storage capacity in North America was identified.
But wait…there’s reality. Currently, carbon capture and storage from coal-fired power plants remains fraught with difficulties. American Electric Power’s (AEP) Mountaineer plant had been demonstrating CCS using a slipstream equivalent to 20 MW, or 1.5% of the installed plant capacity. The second phase of the project was placed on hold last year citing economic and policy uncertainties. Southern Company is conducting a similar CCS demonstration at Plant Barry in Mobile, Alabama. At a mere 25 MW, this project is billed as the “largest” carbon capture unit on a coal plant (consider that Plant Barry has a total installed coal-fired capacity of over 1600MW). Southern Company has delayed moving forward with a larger 160 MW CCS project. The reasons behind the limited demonstration of CCS in the U.S. are numerous:
Footprint: CCS equipment takes up a lot of space. Most coal-fired power plants are already land-locked or severely limited in the acreage they have available and directly adjacent to the generating units.
Economics: CCS is expensive. Phase I of AEP’s project cost over $100 million, and that was just for 1.5% of carbon emission capture. Regulated utilities in the U.S. must get approval from public utility commissions to fund improvements necessary to meet environmental regulations (i.e. rate cases). As greenhouse gas regulations are still in the proposal stage, it would be unlikely for utilities to recover the tremendous investments in CCS technology before a final regulation is promulgated. And before they can make that investment on their own dime, they have also have stakeholders to answer to.
Energy Penalty: Running the CCS system requires about 1/3 of the electric power generated for the portion of the emissions captured. In other words, to capture 100MW of emissions a plant must generate 130MW. That’s a lot of excess power required, and of course more coal mined, transported, and burned. Although studies are underway to lower the energy penalty, the technology has not been demonstrated at full-scale.
The DOE/NRCan/SENER atlas is encouraging for carbon storage potential, but there is a long way to go before CCS is a utility-scale reality. Making it happen requires that we take a long-range, coordinated approach to our energy and environmental policies while investing in technological improvements.