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Underground Natural Gas Working Storage Capacity

With Data for November 2013   |   Release Date:  February 28, 2014   |  Next Release Date: February 2015

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Natural Gas Storage Capacity Rises in West and Producing Salt Regions

U.S. natural gas storage capacity grew 2% in 2013, led by strong gains in salt-based storage in the traditional Producing region as well as in nonsalt storage fields in the West. In contrast, there was almost no growth in storage capacity in the East.

EIA found approximately 2% increases in each of its two measures of storage capacity, which include (1) demonstrated capacity, or the peak volume of gas actually injected into the 407 active storage facilities in the Lower 48 states; and (2) design, or physical, storage capacity. However, there were significant regional disparities (see table).

The U.S. Energy Information Administration (EIA) for years has divided the country into three storage regions: East, West, and Producing. With newer technology, all three regions today have natural gas production, consumption, and storage. Working gas, which is the volume of stored gas available for use, is roughly balanced 50-50 between the East and the two other regions combined.

Table 1. Estimates of Underground Natural Gas Storage Demonstrated and Design Capacity, as of November 2012 and November 2013
(billion cubic feet, unless otherwise noted)
  Demonstrated Maximum Working Gas Volume1 Working Gas Design Capacity2 Demonstrated Maximum Working Gas Share of Working Gas Design Capacity
Region (Dec 2007 - Nov 2012) (Dec 2008 - Nov 2013) Percent
Nov 2012 Nov 2013 Percent
Nov 2012 Nov 2013
East 2,201 2,201 0.0% 2,300 2,305 0.2% 95.7% 95.5%
Producing 1,447 1,487 2.8% 1,522 1,572 3.3% 95.1% 94.6%
   Salt 371 395 6.5% 407 449 10.3% 91.2% 88.0%
   Nonsalt 1,077 1,091 1.3% 1,114 1,123 0.8% 96.7% 97.2%
West 616 645 4.7% 753 804 6.8% 81.8% 80.2%
Lower 48 4,264 4,332 1.6% 4,575 4,681 2.3% 93.2% 92.5%
(1) Demonstrated maximum working gas volume is the sum of the highest storage inventory levels of working gas observed in each facility over the previous 5-year period as reported by the operator on the Form EIA- 191, Monthly Underground Gas Storage Report. The timing of the peaks for different facilities need not coincide.

(2) Working Gas Design Capacity is an estimate of a natural gas facility's physical working gas capacity as reported by the operator on the Form EIA-191 Monthly Underground Gas Storage Report, and represents the sum of the results across all fields at a point in time. It is a measure based on the physical characteristics of the reservoir, installed equipment, and operating procedures particular to the site that is often certified by federal or state regulators.

Note: Design capacity information for all facilities, including inactive fields, is available in the Natural Gas Annual Respondent Query System. Totals may not equal sum of components because of independent rounding. Information about storage regions is available at Storage Basics.

Sources: Form EIA-191, Monthly Natural Gas Underground Storage Report and predecessor surveys.

For the rolling five-year period ending in November 2013, EIA found a 6.5% increase in demonstrated capacity in the Producing Salt region, which rose to 395 billion cubic feet (Bcf). This capacity is the sum of peak volumes actually injected into those facilities, regardless of when the individual peaks occurred over the five-year period. Likewise, the West's demonstrated peak capacity rose 4.7% over the same period to 645 Bcf.

Meanwhile, the East region remained flat at 2,201 Bcf and the Producing Nonsalt region rose 1.3% to 1,091 Bcf; the average for the Producing region was an increase of 2.8%.

The total demonstrated maximum working gas volume in the Lower 48 states rose 1.6%, or 68 Bcf, to 4,332 Bcf for the five-year period ending November 2013.

EIA's data on demonstrated capacity come from monthly surveys of storage operations. Storage peaks typically occur in October or November each year in preparation for the winter heating season; thus, November is a good month to take the measure of working gas actually injected into storage facilities. For demonstrated capacity, the reason for using a rolling period is to capture the actual peaks that likely would not occur simultaneously across all 407 active facilities.

Working gas design capacity is calculated annually rather than in rolling five-year periods. As of November 2013, the Producing Salt region led the nation with a 10.3% increase to 449 Bcf, compared with November 2012. The West rose 6.8% to 804 Bcf. The Producing Nonsalt region rose 0.8%, to give the Producing region an average increase of 3.3% to 1,572 Bcf. The East rose only slightly, by 0.2%, to 2,305 Bcf.

Thus, total working gas design capacity as of November 2013 was up year-over-year by 2.3%, or 106 Bcf, to 4,681 Bcf.

Working gas design capacity is an engineering measure of the estimated maximum volume of working gas that physically can be stored in an underground facility given its design specifications, physical characteristics, compression equipment, temperature, and pressure.

For the one-year period ending November 2013, expansion projects led most of the 106-Bcf increase in design capacity for the Lower 48 states. Only two new fields began operations during 2013, together accounting for about half of the 50-Bcf year-over-year increase in design capacity in the Producing region alone. Two expansion projects in the West accounted for 50 Bcf, or nearly all, of the year-over-year increase in design capacity in the region during 2013.

Most of currently planned storage projects are in the Producing Salt and West regions. Completion of these storage projects in 2014 could increase design capacity by 63 Bcf, including 50 Bcf from facilities currently under construction. New salt facilities currently under construction in the Producing region account for 22 Bcf of the additional working gas capacity. In the West, completion of new facilities could increase design capacity by 28 Bcf. Expansion of existing facilities totaling 13 Bcf of new capacity also is planned for 2014.