What led EIA to change the Weekly Natural Gas Storage Report (WNGSR) reporting from three to five regions?

The three storage regions were developed more than 20 years ago when the dynamics of the natural gas market, including producing and consuming regions, were different than they are today. The new storage regions better reflect groupings of storage locations and the production and demand areas they serve. They also provide more detailed data. The new regions were initially proposed in 2014 and outlined in the Federal Register as part of the Weekly Natural Gas Storage Report's (WNGSR) Office of Management and Budget clearance process. Public comments from this process helped EIA determine the final boundaries for the regions.

Are the new regions just a further breakout of the current three regions? What changed?

The reporting regions for the WNGSR have been redrawn to reflect changes in natural gas production and transportation over the past several years. These changes are expected to improve understanding of natural gas flows in the Lower 48 states. The Producing region is now called the South Central region, and it no longer contains New Mexico, which is now in the new Mountain region. The West region is split into the Mountain and Pacific regions, and it no longer contains Minnesota, which is now in the Midwest region. The East region is broken into the new East region and the Midwest region, and it no longer contains Nebraska, which is now in the Mountain region. A map and table of the new listings are available on the August 31, 2015, new region announcement.

Will EIA continue to publish data for the original three regions in addition to data for the new storage regions?

EIA will continue to publish monthly storage data at the state level but the weekly data will only be available for the new regions once the change is implemented. The historical data for the original three regions will continue to be available on an archive page, which will be made available on November 16, 2015.

Why are there differences between the U.S. totals for five regions and the previously published U.S. totals for three regions?

Differences between the U.S. levels for the new five-region structure and the current three-region data come from several different sources. The new five-region historical data from January 2010-June 2015 were derived by reallocating previously submitted respondent-level data and previous estimates for nonsampled respondents. As a result, differences between the previously published three-region history and the new five-region history through June 12, 2015, primarily result from independent rounding and typically total less than one or two billion cubic feet.

Beginning with data for June 19, 2015, EIA has generated weekly estimates using respondent data for the new five regions. As a result, data for June 19, 2015, through November 16, 2015, may be different from the previously published three-region history and the new five-region history. These differences derive from the re-estimation of the nonsample companies, independent rounding, and previously unpublished revisions that may have fallen below the old 7 Bcf revision threshold.

The estimated five-region data were updated on November 5 to include the weeks of June 19, 2015, to October 16, 2015. This second set of comparative data matches the previously published Lower 48 total in some weeks and is as high as 8 Bcf different from the published three-region data. The absolute average difference is 2.4 Bcf. The final weeks of five-region history will be released when the five-region format is implemented November 16, 2015.

What companies are currently reporting data to EIA? Can I get a copy of the respondent-level data so I can build my own history?

The data submitted on the Weekly Natural Gas Storage Report (Form EIA-912) are protected under the Confidential Information Protection and Statistical Efficiency Act, which precludes EIA from providing any identifiable information about the companies that report to EIA. However, monthly storage data on all operators, including operator name, location, and capacity, are available in EIA's public query system.

When will EIA change to the new regions?

The report published on November 13, 2015 for the week ending November 6, 2015, will be the final report issued in the three-region format. On November 16, 2015, at 3:00 p.m., the three-region data for the week ending November 6, 2015, originally published November 13, 2015, will be replaced with five-region data for the same report week ending November 6, 2015. The data for the week ending November 13, 2015, will be released at the normal release time, 10:30 a.m., Thursday, November 19, 2015, in the five-region format only.

What other changes will be made to the WNGSR?

Two revision policy changes and a new rounding procedure also will go into effect with the new regions.

Revisions: First, the publication threshold for reporting reclassifications and revisions to WNGSR data will decrease from 7 Bcf to 4 Bcf. Second, the new out-of-cycle revision policy requires EIA to publish a revision when a net change of 10 Bcf or greater is reached from changes and corrections for the two most recent reporting weeks. The previous out-of-cycle revision policy did not require that the threshold be reached for the most recent two weeks; the threshold could have been reached by an accumulation of changes or corrections that occurred over longer periods.

Further information on these changes is contained in the August 31, 2015, announcement under "Data Revision Policy."

Rounding: Currently, the storage stocks reported in each region are rounded, and then the Lower 48 total is calculated as the sum of those rounded values. As a result, the sum of the three regions always equals the Lower 48 total. Under the new five-region format, the Lower 48 total will be calculated, then each region and the national total will be rounded individually to the nearest Bcf. This could result in the sum of the five regions differing from the Lower 48 total by as much as 2 Bcf in a given week. This is a more methodologically-sound approach, as rounding is typically the very last step in an algebraic operation.

The week-on-week net change, however, will continue to be calculated from the rounded numbers. In other words, in any given region, the difference between the current week and the previous week stocks will always exactly equal the net change for that region.

How can I stay informed of future developments related to these changes?

The Natural Gas Underground Storage Email list is a great way to stay current. Notices will go out each time there is information about the new regions to share, as well as any changes to the publication schedule or out-of-cycle revisions. Nevertheless, keeping an eye on the WNGSR page remains the best and most timely way to stay current.

For questions, contact Jose Villar at (202) 586-9613 or jose.villar@eia.gov.