UNDERGROUND STORAGE OF REFRIGERATED NATURAL GAS IN GRANITES IN NORTH CAROLINA AND SOUTHERN VIRGINIA

Conventional underground storage sites for natural gas (salt caverns, depleted gas and oil reservoirs, and aquifers) are either rare or absent along the eastern seaboard of the U.S. However, in this region the potential exists for underground storage of refrigerated natural gas in mined caverns (RMC) in granite. We present the results of a study that examines pipeline-granite intersections in North Carolina and southern Virginia along the Williams/Transco pipeline (completed) and the Atlantic Coast Pipeline (planning and initial stage). With Google Earth Pro we took granite outlines from USGS digital state geologic maps and show those that are intersected by the pipelines. Search engines provided by the USGS provide more detailed information on the granites identified in this study. The USGS National Geologic Map Database is particularly useful as it provides detailed maps (geological, geophysical, and geochemical) of any particular area in the U.S. Many of these maps can be downloaded from their website. In addition, we use the conceptual design for a mined cavern in granite in the Maryland piedmont given in a 1998 DOE sponsored study* as an example of the type of natural gas storage cavern that could potentially be adapted for use in the NC and VA granites. Liquid Natural Gas (LNG) plants are judged to be more competitive at the present time principally because of lower capex. However, RMC plants can meet multiple peak demands per year whereas LNG plants are limited in their cycle time. Existing knowledge of geology and locations of granite rock with potentially suitable geotechnical properties in the NC and southern VA region, coupled with modern advances in hard rock excavation technology, argue for the overall technical viability of the concept. Commercial viability, however, will depend on site specific conditions, market analysis, and other considerations requiring additional study.

*PB-KBB, 1998, “Advanced Underground Gas Storage Concepts Refrigerated-Mined Cavern Storage, Final Report, DOE Contract Number DE-AC26-97FT34349, 162 pages. Available at http://www.netl.doe.gov/KMD/cds/Disk19/FinalRpt.pdf.