Yesterday’s release of EIA’s March 2022 Petroleum Supply Monthly now reports inventories of hydrocarbon gas liquids (HGL) that include volumes of ethane, propane, normal butane, isobutane, and natural gasoline at end-user storage facilities as part of our reported wholesale terminal stocks. Starting in January 2021, we expanded the scope of our Monthly Bulk Terminal Report to include HGLs held by selected end users with at least 50,000 barrels of storage capacity and by smaller facilities that can ship products by pipeline, tanker, or barge. This more comprehensive approach to inventory accounting also affects our estimate of product supplied, which we use as a proxy for consumption of petroleum products. Revisions that increase inventory builds will tend to lower our estimate of product supplied and vice versa.

Starting with yesterday’s March 2022 Petroleum Supply Monthly, monthly reported HGL inventories in January 2022 and all subsequent months will reflect stocks at all bulk terminals, including end-user storage facilities meeting the reporting requirements. Later this year, we will also revise monthly HGL inventory values for 2021.

Each Petroleum Supply Monthly includes an appendix table of data revisions for several major data series, including for total HGLs and propane. In yesterday’s release, this appendix, Impact of Revisions on Major Series, 2021, shows the effects of the survey change for total U.S. HGL inventory and, within HGLs, U.S. propane inventory for monthly values going back to January 2021. The revised data for 2021 will not appear in tables currently published on our website until the release of the August 2022 Petroleum Supply Monthly and the 2022 Petroleum Supply Annual.

With this revision, we found that U.S. HGL stocks during some months of 2021 were as much as 10 million barrels greater than our published values. In October 2021, total U.S. HGL inventories reached 235.7 million barrels, which is 5.4 million barrels more than the currently published total of 230.3 million barrels.

In February 2021, when a winter storm limited much of the petrochemical consumption in the Gulf Coast region, the revised inventories reduce product supplied by nearly 80,000 fewer barrels per day (b/d) of U.S. HGL consumption. In October 2021, when the price of propane and other HGLs rose rapidly, revised inventory data show a slower build in stocks, resulting in an additional 146,000 b/d of U.S. HGL product supplied above currently reported values, approximately 45,000 b/d of which was propane.