The goal is to develop alternatives for natural gas storage in market areas where conventional storage options may be technically unfeasible.
Sofregaz US, Inc.– project management and research product
Itasca Consulting Group – Independent technical reviews
Houston, Texas 77079
The LRC concept has been under development in Sweden for more than 15 years. The concept involves constructing a storage cavern and lining it with an inner, gas-tight steel liner encased in a layer of concrete. The concept may have application in areas of the U.S. where hard rock formations exist but where conventional underground gas storage is limited or nonexistent (e.g., the Northeast, Southeast Atlantic, and Pacific Northwest).The underground facility consists of one or more storage caverns excavated in rock as vertical cylinders, a vertical shaft for gas transfer, and a system of tunnels connecting the caverns with the ground surface. The caverns would be located at a depth of about 300-600 feet below ground and the maximum storage pressure would be in the range of 2,200-4,350 psi. A typical cavern would be 100-120 feet in diameter, 200-340 feet in height, and have 400-1,100 million cubic feet (MMcf) of natural gas storage (working volume) capacity.
Injection into the cavern would be done directly from the pipeline by flow control when the storage pressure is lower than the pipeline pressure. When the cavern pressure is higher than the pipeline pressure, compression would be used. During gas injection, when the pressure is higher in the cavern than in the pipeline, some gas will be withdrawn from the cavern by a separate compressor, cooled, and injected back into the cavern to increase the working gas volume in the cavern. Withdrawal would normally be accomplished by free flow from the cavern to the transmission line, with compression used when the storage pressure falls below the pipeline pressure.
The project demonstrated a successful conceptual design of an LRC facility. Conclusions from the study for Boston (or the Northeast market in general) were that lined rock caverns could lower costs for long haul transportation through de-contracting, be competitive with liquefied natural gas through cycling, and be useful in pipeline pressure balancing.
For this project, a composite map was completed showing the various hard rock formations suitable for LRC, the major gas pipelines, and market hubs. The general gas supply and demand situation was evaluated for the three regions of Boston, New York, and Atlanta. Boston and Atlanta were selected as the two geological cases for the study, based on geologic suitability.
The results demonstrated that LRC could provide better service than liquefied natural gas peak shaving plants (because of its ability for multiple cycles) and also that it could lower cost for long haul transportation in the Northeast. Two facilities, an eight-cavern, 5.2 billion cubic foot working gas facility near Atlanta, Georgia, and a four-cavern, 2.6 billion cubic foot working gas facility near Boston, Massachusetts, were investigated. Conclusions from the study for Atlanta, or the Southeast market in general, were that while it would be difficult for LRC to compete with long haul transportation by de-contracting, it would be competitive with liquefied natural gas through cycling, and would be useful in pipeline pressure balancing.
The conclusion was that there is some potential for commercialization of the LRC technology in the United States. Investment costs for an LRC facility in the Northeast are high: approximately $182 million for a 2.6-billion cubic foot (bcf) working gas facility and $343 million for a 5.2-bcf working gas storage facility (1998 dollars).
This project is completed.
NETL – James Ammer (email@example.com or 304-285-4383)
Sofregaz US, Inc. – Michel A. Dussaud (281-531-5685)
Itasca Consulting Group – Branko Damjanac (612-371-4711)
Advanced Gas Storage Concepts: Technologies for the Future, February 1, 2000.
Technical Review of the Lined Rock Cavern (LRC) Concept and Design Methodology: Mechanical Response of the Rock Mass. September 2001. Itasca Consulting Group.
Technical Review of the Lined Rock Cavern (LRC) Concept and Design Methodology: Steel Liner Response. August 2002. Itasca Consulting Group.
Based on the positive findings of the commercialization potential study, NETL contracted Itasca Consulting Group to review several key aspects of the LRC design. The first phase of this review, Mechanical Response of the Rock Mass, emphasizes two key LRC design criteria associated with (1) safety against ground uplift, and (2) a maximum operating (cyclic) strain range in the steel liner.
The review found the implementation of the LRC concept to be a carefully planned incremental design procedure. Although of considerable proportions, the lined rock cavern size is not unprecedented. There is extensive worldwide rock engineering experience in developing large complex rock caverns. By following established principals, one should expect that stable, large, lined rock caverns can be constructed in different lithology rocks of reasonable quality. During cavern operation, the combination of shallow cavern depth and high gas pressure makes the LRC concept unique in terms of the cavern loads, and the structural integrity of the steel liner must be maintained for these loads. By adopting a careful design methodology that considers the detailed interaction of the rock mass and cavern wall response, and a design implementation that is guided by physical observations during cavern construction, one should expect to develop LRC storage that will operate successfully for a level of gas pressures as high as 25 MPa in a rock mass of reasonable quality.
The second technical review conducted by Itasca was concerned mostly with the second key aspect of the LRC concept: the structural integrity and “constructability” of the steel liner. Particular attention was paid to the production pipe (nozzle) and the connection between the production pipe and the cavern. Deformation and stresses in the cavern liner for the most critical loading conditions were analyzed numerically. The review concluded that the LRC concept seems feasible from the standpoint of the structural integrity of the steel liner. The analyses of the fracture and fatigue of the steel liner appear to be well substantiated and sufficiently conservative.
A full-scale LRC demonstration facility has been constructed at Skallen, a site near the coastal city of Halmstad in southwest Sweden. The facility has undergone extensive pressure testing and was expected to be ready for operation by late 2003.