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Underground Natural Gas Working Storage Capacity

With Data for November 2014   |   Release Date:  February 25, 2015   |  Next Release Date: February 2016

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Natural Gas Storage Capacity Unchanged Nationally, but Regions Vary

Against a backdrop of low natural gas storage levels throughout 2014 and high levels of production, U.S. natural gas working storage capacity as of November 2014 was virtually unchanged from its November 2013 level. Continued gains in the capacity of salt caverns in the Producing region offset capacity declines in the East. Capacity in the West and Producing Nonsalt regions both increased slightly, but with minimal effect on the national total.

The U.S. Energy Information Administration (EIA) uses two distinct measures of natural gas storage capacity:

Demonstrated maximum working gas volume: This measure represents the sum of peak volumes reported by the 395 active storage facilities in the Lower 48 states, regardless of when the individual peaks occurred over the most recent five-year (December 2009-November 2014) period.

The total demonstrated maximum working gas volume in the Lower 48 states was nearly unchanged between November 2013 and November 2014, rising by just 0.1%, or 3 billion cubic feet (Bcf).

Design capacity: This measure is the sum of the 395 active storage fields' working gas design capacity, as of November 2014, as reported on survey Form EIA-191, Monthly Underground Natural Gas Storage Report. Design capacity is 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.

The total design capacity in the Lower 48 states was also nearly unchanged between November 2013 and November 2014, rising by just 0.02%, or 1 Bcf.

The modest change in capacity this year compared with previous reports reflects both low storage volumes and the absence of new storage facilities.

Low storage volumes: For nearly all of 2014, and in all regions except the Producing Salt region, natural gas storage levels were below the previous five-year (2009-13) minimum. This was after large withdrawals during the winter of 2013-14, which featured extremely cold weather during January and February.

No new underground storage caverns: Since November 2013, no new storage facilities have begun operation. Increases in working gas design capacity came from expansions to existing caverns.

Most of the expansions occurred in the Producing Salt region, where four different caverns expanded, increasing the region's overall design capacity by 33 Bcf (7.3%). One of the expanded caverns accounted for 13 Bcf of this growth. The entire Producing region (salt and nonsalt) increased its design capacity by 28 Bcf (1.8%). For the five-year period ending in November 2014, demonstrated working gas capacity in the Producing Salt region rose by 17 Bcf (4.4%) compared with the previous five-year period. Total Producing region demonstrated capacity (including both the Salt and Nonsalt storage) increased by 1.1%, an increase of 16 Bcf.

The growth in design capacity in the Producing region was almost entirely offset by a 1.3% decline in design capacity in the East region because of two fields that became inactive in 2014. One of the fields, a depleted reservoir, accounted for 28 Bcf of the East region's 30 Bcf decline. Showing a smaller decline of less than 0.5%, total demonstrated capacity in the East region fell by 10 Bcf, decreasing from 2,202 to 2,192 Bcf.

Estimates of Underground Natural Gas Storage Demonstrated and Design Capacity, as of November 2013 and November 2014
(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 2008 - Nov 2013) (Dec 2009 - Nov 2014) Percent
Nov 2013 Nov 2014 Percent
Nov 2013 Nov 2014
East 2,202 2,192 -0.43% 2,304 2,275 -1.29% 96% 96%
Producing 1,486 1,503 1.10% 1,556 1,584 1.77% 96% 95%
   Salt 395 412 4.39% 448 481 7.27% 88% 86%
   Nonsalt 1,091 1,090 -0.10% 1,108 R 1,103 -0.46% 99% 99%
West 645 641 -0.56% 804 807 0.39% 80% 80%
Lower 48 4,333 4,336 0.08% 4,664 4,665 0.02% 93% 93%
(1) Demonstrated maximum working gas volume is the sum of the highest storage inventory levels of working gas observed in each distinct storage reservoir over the previous five-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. Inactive fields were removed from aggregate statistics.

(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. It represents the sum of all fields' capacities 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. Inactive fields were removed from aggregate statistics.

Note: Design capacity information for all facilities, including inactive fields, is available in the Natural Gas Annual Respondent Query System. Monthly data are available for January 2014 on. Totals may not equal sum of components because of independent rounding. Information about storage regions is available at Storage Basics. The revised data point for Nonsalt Working Gas Design Capacity, denoted with an R superscript, was due to an inactive field that was incorrectly classified as active during the last peak capacity report.

Sources: Form EIA-191, Monthly Natural Gas Underground Storage Report

Percent change in storage capacity from 2013 to 2014 graph

Most currently planned storage projects are concentrated in salt formations, likely because of their high deliverability rates. Salt domes are capable of sending out gas within a short time, sometimes within an hour, making them more responsive to customer demand than other types of underground storage.

Unlike gas storage in depleted fields or aquifers, which generally cycle in and out once a year, salt dome storage can cycle many times a year, although in much smaller volumes. As a result, salt dome storage is useful to meet unexpected demand — such as during a cold snap — and then be quickly refilled. Salt dome storage can also be used for financial arbitrage, allowing capacity owners during any part of the year to take advantage of gas price increases.

EIA has traditionally divided the country into three storage regions: East, West, and Producing. The East region, which historically has been a net consuming region of natural gas, has large volumes of storage to meet higher consumer demand during the winter. Working gas capacity in the East region is comparable with the combined storage capacity of the West and Producing regions. EIA will introduce new storage reporting regions later in 2015.

In late 2014, EIA gained approval to collect and publish storage data in additional regions. The new regions will be reflected in weekly, monthly, and annual storage reports later in 2015. See the EIA-912 report form for a description of the new regions.

Storage regions map