The U.S. Strategic Petroleum Reserve (SPR) has dipped below 300 million barrels for the first time in decades, sparking concerns among experts about potential damage to the vital salt caverns that store the oil. This rapid drawdown, primarily in response to global energy crises, risks compromising the SPR’s ability to function effectively during future emergencies. Officials and energy analysts warn that further depletion could lead to irreversible damage and reduce the reserve’s long-term viability.
Experts are raising alarms as the U.S. Strategic Petroleum Reserve (SPR) experiences a rapid drawdown, nearing levels that could potentially damage the underground salt caverns used for storage and compromise future emergency response capabilities. Federal data released this week reveals that the SPR has fallen below 300 million barrels for the first time since its inception in the early 1980s.
The SPR, comprised of oil stored in 60 salt caverns along the Gulf Coast in Louisiana and Texas, is being depleted as the U.S. releases significant volumes in response to global energy disruptions. This extensive release, totaling 172 million barrels, is projected to leave the reserve at approximately 243 million barrels once completed.
The U.S. Department of Energy has previously indicated that a minimum of 70 million barrels is necessary to safely manage the caverns. However, Amos Hochstein, a senior energy advisor to President Joe Biden, has publicly disputed this figure, labeling claims that the SPR can be drawn down to 70 million barrels as "nonsense." He warned that such a low level could render the reserve "never resurrecting it" and emphasized the physical risks to the caverns.
Hochstein reiterated his concerns in June, stating that "I don't know anyone who believes we can go below 300." He elaborated that many experts believe approaching 300 million barrels risks physically damaging the storage caverns.
A spokesperson for the Energy Department, Ben Dietderich, has countered these claims, asserting that the caverns are "always full" and that only the ratio of oil to water changes. He stated that the administration is "responsibly managing the SPR as the critical national security asset it was designed to be."
Despite the Department's assurances, concerns about cavern integrity have been voiced across the political spectrum. Republican lawmakers previously raised similar issues during the Biden administration's record drawdown of 180 million barrels in response to Russia's invasion of Ukraine in 2022. The SPR fell below 350 million barrels in 2023 before being refilled to around 415 million barrels prior to the recent drawdown.
A May report from the Government Accountability Office (GAO) noted that "repeated partial drawdowns followed by refill can leach a single part of a cavern repeatedly, leading to undesirable shapes." While the GAO found most caverns in "very good condition" after the 2022 drawdown, it warned that "every drawdown cycle expands cavern volume and reduces the spacing between caverns within the salt dome, which ultimately reduces their long-term viability."
The process of releasing oil from the SPR involves pumping water into the bottom of the caverns to displace crude to the surface. Siddharth Misra, a petroleum engineering professor at Texas A&M University, explained that 70 million barrels is the strict physical minimum required to keep extraction pipes submerged in oil. However, he identifies the "practical operational floor for the crude inventory" to be between 250 million and 300 million barrels, stating that at current levels, "cavern integrity and overall operational capability are at an elevated risk."
Below 300 million barrels, Misra noted, the SPR's ability to pump oil rapidly during emergencies diminishes. The system's infrastructure could also face damage as the oil layer thins and sludge rises. The injection of fresh water during rapid drawdowns can dissolve salt walls, thinning salt pillars between caverns and increasing the risk of structural collapse.
The SPR was originally designed for five full drawdowns but has undergone dozens over its 40-year history. Misra stated that this frequent usage has led to significant cavern deformation, accelerated salt falls from ceilings, and weakened the overall structural integrity. Energy Department officials have reportedly told the GAO that the SPR infrastructure is being held together with "Band-Aids" and that its long-term stability is uncertain.
Analysts at Rapidan Energy estimate a "soft-ish floor" of around 170 million barrels, below which cavern integrity and pumping limitations would prevent further draws. Hochstein concluded that with inventories below 300 million barrels, the U.S. would be in a precarious position during a crisis like a hurricane, where "it slows the flow and puts us in danger."
