NETL is investigating novel storage concepts that may allow greater flexibility in locating sites for future storage facilities.  One avenue under investigation is the potential of storing gas within the thick volcanic deposits of the Columbia Basin region in the Pacific Northwest.  A second alternative involves the freezing of gas with water into dense “hydrate” structures.

Hydroelectric dams supply a major portion of the power for the Pacific Northwest.  However, future energy demands cannot be met by hydroelectric power alone, especially if current ideas to remove some dams to restore natural environments are implemented.  In any scenario, power plants fueled by natural gas are the most feasible and environmentally-sensitive alternative.  Although natural gas supply lines transverse the northwest, the gas storage capacity needed to support the plants is not yet available in the region.  The occurrence of thick sequences of Columbia River basalts within the Columbia Basin (situated between the Cascade Range and the Rocky Mountains), however, offers a high potential for new, unconventional subsurface natural gas storage.

The layered basalts of the Columbia Basin are typically very dense, while the rapidly-cooled upper parts of each flow are commonly very porous.  In fact, small volumes of natural gas were produced from porous basalt layers in the early part of the last century.  While the prospect of utilizing basalt flows for gas storage is intriguing, important questions regarding the size, permeability, and integrity of potential reservoirs remain.  The principal aim of DOE-sponsored studies is to provide the natural gas storage industry with the best methods and tools to fully evaluate the storage potential at various sites in the Columbia River basin.

NETL's Oil and Natural Gas Program is also investigating the feasibility of storing natural gas in the form of gas hydrates.  Currently, users of coal and oil can safely store large volumes of reserve at their plant site.  This is much more difficult with natural gas – not only because of its flammability, but also because it typically must be stored under pressure to reduce it to manageable volumes.  However, when frozen in the presence of water, natural gas  produces a stable, compact structure that can be  thawed as needed to release the gas.  Hydrates are an incredibly efficient method for storing gas; theoretically, 181 standard cubic feet (scf) of gas can be stored per cubic foot of hydrate.  However problems relating to how fast and how efficiently the hydrates form must be overcome to make the process practical.  Initial results have shown that many of these barriers can be removed through use of a surfactant (sodium dodecylsulfate).  This process has efficiently formed hydrates in the laboratory at 86% of theoretical gas capacity within 3 hours of hydrate initiation – an improvement over previous methods by a factor of 700.  Based on these findings, additional work has been conducted to prepare a conceptual design and an economic analysis for a large-scale process.