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Underground Natural Gas Working Storage Capacity

With Data for November 2020 Release Date: April 30, 2021 Next Release Date: April 2022
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Natural gas storage capacity remained essentially unchanged in 2020

EIA's two metrics for assessing underground working natural gas storage capacity in the Lower 48 states showed mixed results for 2020 compared with 2019. Design capacity reported a small increase, and demonstrated peak capacity reported a small decrease.

  • Design capacity: Design capacity, sometimes referred to as nameplate capacity, is based on the physical characteristics of the reservoir, installed equipment, and operating procedures on the site, which often must be certified by federal or state regulators. We calculated design capacity as the sum of the reported working natural gas capacities of the 387 active storage fields in the Lower 48 states as reported on Form EIA-191, Monthly Underground Natural Gas Storage Report, as of November 2020. We excluded the 25 inactive fields in the Lower 48 states from the total. The design capacity metric is a theoretical limit on the total amount of natural gas that can be stored underground and withdrawn for use.
  • Demonstrated peak capacity: Demonstrated peak capacity, or total demonstrated maximum working natural gas capacity, represents the sum of the largest volume of working natural gas reported for each individual storage field during the most recent five-year period, regardless of when the individual peaks occurred. In this report, the most recent demonstrated peak covers the November 2020 report period (December 2015 through November 2020). Demonstrated peak capacity is based on survey data from Form EIA-191 and is typically less than design capacity because it relates to actual facility usage, rather than potential use based on the design of the facility.

Natural gas design capacity was essentially unchanged in 2020; however, some operators revised earlier estimates, increasing working gas capacity. Design capacity of underground natural gas storage facilities in the Lower 48 states increased by 4 billion cubic feet (Bcf), or 0.1%, in the November 2020 report period compared with the November 2019. A couple of notable revisions increased working gas capacity reported for 2019 in the Mountain and Pacific regions, which reflects the operators’ reassessments of the operational characteristics of the affected fields.

  • In the Mountain region, Spire Storage West revised the working gas capacity at the Belle Butte field (formerly Ryckman Creek) up by 16 Bcf to 35 Bcf as of February 2019. Spire Inc. acquired Ryckman Creek Resources and Clear Creek Storage in Wyoming in 2018. After this acquisition, Spire Storage West reported reduced working natural gas capacity at the Belle Butte (formerly Ryckman Creek) field by 16 Bcf. The field’s estimated operational capacity in 2019 was 19 Bcf, compared with 35 Bcf in 2018. However, Spire Storage West has since decided to operate the Belle Butte field at the FERC-authorized working gas capacity of 35 Bcf. Aside from this revision, working gas capacity remained unchanged in the Mountain region during 2020.
  • Working natural gas design capacity increased by 5 Bcf in the South Central region. The most notable increase in the region was the 4.2 Bcf gain reported for the Egan Storage Dome by Egan Hub Partners. Dewatering the salt cavern raised the capacity of this field.
  • In the Pacific region, the Northwest Natural Gas Company revised the working gas capacity for the Mist field in Oregon, increasing capacity by 1.5 Bcf to 4 Bcf for 2019. The North Mist capacity expansion came came online in May 2019. Northwest Natural revised its early estimates of the design capacity of the Mist field—the only new natural gas storage reservoir to come online in 2019—based on the observed operational characteristics of the facility. Working gas capacity remained unchanged at the facility in 2020.

Demonstrated peak capacity decreased in 2020 as the decline in the Pacific region more than offset gains reported in other regions. Overall, demonstrated peak capacity declined by 8 Bcf, despite reported increases in five of six regions in the Lower 48 states as of the November 2020 report period compared with the November 2019 report period. Despite the net decline in demonstrated peak capacity for the Lower 48 states, the overall trend was toward increased usage of natural gas storage and higher working natural gas storage levels for the second year in a row.

  • Demonstrated peak capacity declined by 34 Bcf in the Pacific region because previous peak levels—predating the 2015 natural gas leak at the Aliso Canyon natural gas storage facility in California—are no longer included in the five-year range (December 2015–November 2020). The Aliso Canyon field has operated at reduced levels since coming back online following the leak. Despite the decline in demonstrated peak capacity for the region, natural storage facilities in the Pacific region also saw increased usage during 2020 like in the other regions.
  • The South Central region reported the biggest increase in demonstrated peak capacity in 2020, increasing 10 Bcf (0.7%) over the previous year. Salt facilities accounted for 8 Bcf of this year-over year increase. The Midwest had the next largest increase at 7 Bcf, followed by the Mountain region at 7 Bcf and the East region at 3 Bcf.

In recent years, several offsetting trends have affected the industry’s decisions about changes to underground storage capacity levels. Several recent trends may have reduced the need for investment in additional underground storage:

On the other hand, other factors could increase the need for additional storage:

Working natural gas in storage reached its highest level since 2016: Working gas stocks ended the November 2020 report period at its highest level since 2016, despite decreased natural gas production and continued high demand for natural gas in electricity generation and for export. The higher natural gas storage level was partly because working gas entered the refill season, in April, at 2,006 Bcf —its highest level since 2017— following a relatively mild winter.

Estimates of demonstrated peak and design capacity of underground working natural gas storage, November 2020
(billion cubic feet, unless otherwise noted)
  Demonstrated peak capacity1 Design capacity2 Demonstrated peak capacity share of design capacity3
Region (Dec 2014 - Nov 2019) (Dec 2015 - Nov 2020) percent change Nov 2019 Nov 2020 percent change Nov 2019 Nov 2020
East 988 991 0.3% 1,065 1,065 0.0% 93% 93%
Midwest 1,179 1,186 0.6% 1,221 1,221 0.0% 97% 97%
Mountain 261 267 2.5% 472 R 471 0.0% 55% 57%
Pacific4 404 370 -8.6% 419 R 419 0.0% 97% 88%
South Central 1,429 1,439 0.7% 1,535 1,540 0.3% 93% 93%
Nonsalt 1,009 1,011 0.2% 1,059 1,060 0.1% 95% 95%
Salt 420 428 1.8% 476 480 0.9% 88% 89%
Lower 48 4,261 4,253 -0.2% 4,711 R 4,715 0.1% 90% 90%
Source: U.S. Energy Information Administration, Form EIA-191, Monthly Underground Natural Gas Storage Report
Note: Design capacity information for all underground storage facilities, including inactive fields, is available in the Natural Gas Annual Respondent Query System. Totals and calculations may not equal the sum of the components because of independent rounding. Information about storage regions is available in The Basics of Underground Natural Gas Storage. Mentions of specific companies in this report include only information that is publicly available on our website or on the Federal Energy Regulatory Commission (FERC) dockets. The symbol R indicates that we revised the figures since the previous year’s Peak Capacity Report.

1 Demonstrated peak capacity, otherwise known as the total demonstrated maximum working natural gas capacity, is the sum of the highest storage inventory level of working natural gas observed in each distinct storage reservoir during the previous five-year period as reported by the operator on Form EIA-191, Monthly Underground Natural Gas Storage Report. The timing of the peaks for different facilities do not need to coincide. We exclude inactive fields in estimates of working gas capacity.

2 Design capacity is an estimate of a natural gas facility's physical working natural gas capacity as reported by the operator on Form EIA-191, Monthly Underground Natural 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 are often certified by federal or state regulators. We exclude inactive fields in estimates of working gas capacity.

3 Demonstrated peak capacity in some cases exceeds 100% of design capacity because design capacity limits may differ from actual capacity limits in storage fields, as determined by the facility operator and local regulations.

4 We included the design capacity of Southern California Gas Company’s Aliso Canyon field in this report and in the Pacific region totals as 86.2 billion cubic feet, as publicly reported on Form EIA-191. The authorized working natural gas capacity of this facility may be lower because of ongoing operational constraints.
Year-over-year change in working natural gas capacity graph
Estimates of demonstrated peak and design capacity of underground working natural gas storage, November 2020
(billion cubic feet, unless otherwise noted)
  Demonstrated peak capacity1 Design capacity2 Demonstrated peak share of design capacity3
Region State (Dec 2014 -
Nov 2019)
(Dec 2015 -
Nov 2020)
Change Nov 2019 Nov 2020 Change Nov 2019 Nov 2020
East PA 403 402 -1 418 418 0 96% 96%
WV 234 236 2 243 243 0 96% 97%
MD 16 16 0 18 18 0 90% 90%
VA 5 5 0 5 5 0 107% 107%
OH 210 210 0 253 253 0 83% 83%
NY 119 121 2 127 127 0 94% 95%
Total 988 991 3 1,065 1,065 0 93% 93%
Midwest IL 272 274 1 301 301 0 90% 91%
IA 82 84 2 90 90 0 91% 93%
MN 2 2 0 2 2 0 107% 108%
TN 2 2 0 2 2 0 84% 84%
IN 30 31 1 30 30 0 100% 103%
MO 7 7 0 4 4 0 188% 188%
KY 108 108 0 108 108 0 100% 100%
MI 676 680 3 684 684 0 99% 99%
Total 1,179 1,186 7 1,221 1,221 0 97% 97%
Mountain MT 39 40 1 197 197 0 20% 20%
NE 14 12 -1 13 13 0 109% 109%
UT 53 53 0 55 55 0 96% 96%
NM 50 50 0 60 60 0 83% 83%
CO 61 63 3 73 73 0 83% 87%
WY 45 49 4 74 R 74 0 61% 66
Total 261 267 7 472 R 471 0 55% 57%
Pacific WA 24 24 0 25 25 0 96% 96%
OR 22 23 1 20 R 20 0 111% 115%
CA4 358 323 -35 374 374 0 96% 86%
Total 404 370 -35 419 R 419 0 97% 88%
South Central MS 165 165 0 202 202 0 81% 82%
AR 5 5 0 9 9 0 57% 57%
KS 118 118 0 123 123 0 96% 96%
AL 27 27 1 33 33 0 80% 82%
LA 423 431 8 447 451 4 95% 96%
OK 186 186 0 196 196 0 95% 95%
TX 505 506 2 526 526 1 96% 96%
Total 1,429 1,439 10 1,535 1,540 5 93% 93%
Lower 48 4,261 4,253 -8 4,711 R 4,715 4 90% 90%
Source: U.S. Energy Information Administration, Form EIA-191, Monthly Underground Natural Gas Storage Report
Note:: Design capacity information for all facilities, including inactive fields, is available in the Natural Gas Annual Respondent Query System. Totals and calculations may not equal the sum of the components because of independent rounding. Information about storage regions is available in The Basics of Underground Natural Gas Storage. Mentions of specific companies in this report include only information that is publicly available in our query system.

1 Demonstrated peak capacity, otherwise known as the total demonstrated maximum working natural gas capacity, is the sum of the highest storage inventory levels of working natural gas observed in each distinct storage reservoir during the previous five-year period as reported by the operator on the Form EIA-191, Monthly Underground Natural Gas Storage Report. The timing of the peaks for different facilities do not need to coincide. We exclude inactive fields in estimates of working gas capacity.

2 Design capacity is an estimate of a natural gas facility's physical working natural gas capacity as reported by the operator on the Form EIA-191, Monthly Underground Natural 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 are often certified by federal or state regulators. We exclude inactive fields in estimates of working gas capacity.

3 Peak capacity in some cases exceeds 100% of design capacity because design capacity limits may differ from actual capacity limits in storage fields, as determined by the facility operator and local regulations. Demonstrated maximum working natural gas volume more commonly exceeds design capacity in states with a smaller number of facilities and smaller total storage volumes. In instances where storage fields reduce working natural gas capacity, demonstrated peak capacity may exceed design capacity.

4 We included the design capacity of Southern California Gas Company’s Aliso Canyon field in this report and in the Pacific region totals as 86.2 billion cubic feet, as publicly reported on Form EIA-191. The authorized working natural gas capacity of this facility may be lower because of ongoing operational constraints.