U.S. diesel prices have climbed significantly, reaching an average of $6.30 a gallon-up from $5.90 a month earlier and $3.68 a year ago. This surge drives up operational costs for freight transport, farming, and consumer goods. According to data from AAA, while the national average remained slightly below the record $6.53 set on September 22, regional disparities have hit critical sectors hard. In California, prices surged to $8.35 a gallon, exerting intense financial pressure on one of the country’s major agricultural regions.
While only about 3% of passenger vehicles run on diesel fuel, approximately 76% of commercial vehicles rely on it. This makes fuel costs a foundational driver of broader economic inflation. David Ortega, a food economist at Michigan State University, noted that sustained high prices ripple through every layer of the supply chain. They directly impact the cost of food, manufacturing, and logistics.
The Refiner’s Bottleneck: Why Diesel and Crude Prices Diverge
A common point of public confusion involves comparing current diesel prices with historical crude oil peaks. Consumers frequently note that crude oil prices are lower than they were following Russia’s invasion of Ukraine in 2022. This leads to accusations of price gouging against major refiners like Marathon Petroleum, Valero, and Phillips 66, which collectively posted $12.6 billion in second-quarter earnings.
However, energy analysts and economists emphasize that crude oil and diesel are not interchangeable commodities. Crude is a raw material input, whereas diesel is a manufactured product. Between the oil wellhead and the local fuel pump lies the refining system, which faces severe global capacity constraints.
This dynamic is measured by the diesel crack spread-the difference between the market value of diesel and the crude oil used to make it. In mid-August, the U.S. diesel crack spread briefly topped $100 per barrel for the first time on record, while Asian refining margins surged above $87 per barrel. These wide spreads reflect extreme market scarcity rather than simple markup discretion by refiners, which have recently operated at near-capacity utilization rates touching 98%.
Geopolitical Disruption and Domestic Distribution Constraints
The squeeze on diesel supply stems from multiple compounding disruptions across the globe:
- International Conflicts: Ukrainian drone strikes have forced major Russian refineries to reduce output or shut down units entirely. Meanwhile, Russia has restricted select fuel exports to preserve domestic supplies.
- Middle Eastern Instability: Refining and export infrastructure in the Middle East has faced damage and disruption, alongside severe shipping constraints through the Strait of Hormuz. Reuters estimates that these combined regional shocks have removed roughly 1.6 million barrels per day of diesel and gasoil exports from the global market.
- U.S. Refining Capacity: U.S. operable refining capacity fell from nearly 19 million barrels per day at the start of 2020 down to roughly 18.03 million barrels per day by mid-2026. This drop resulted from pandemic-era closures, storm damage, aging facilities, and conversions to renewable fuels. While not part of a coordinated withholding effort, this reduction leaves the domestic supply chain with virtually zero margin for error.
Compounding the refining deficit is a domestic distribution challenge. According to Phillip Bruner, Professor of Practice of Sustainable Finance Education at the University of Washington’s Foster School of Business, the United States actually possesses a diesel surplus “on paper.” However, much of that inventory is trapped on the Gulf Coast. Pipelines heading to the East Coast are heavily utilized, the West Coast lacks direct pipeline connections, and shipping fuel via coastal tankers is restricted and made costly by federal legislation requiring American-built vessels.
Goldman Sachs Outlook: Elevated Prices Projected Through 2027
Financial institutions expect the pain at the pump to persist. Nikhil Bhandari, Co-Head of Natural Resources Research for Asia Pacific at Goldman Sachs, indicated that diesel prices may need to remain elevated through 2027. The objective is to maintain high refined product prices long enough to force a sustained degree of global demand destruction. This will allow governments and corporations to successfully rebuild depleted fuel inventories.
Until damaged international refineries return to service, global export corridors recover, and domestic transportation bottlenecks are cleared, diesel prices will likely remain stubbornly high. This will anchor inflation across freight and agricultural markets for the foreseeable future.
