Diesel prices hit record highs amid global supply disruptions

The price of diesel fuel hit a record Friday as the wars in Ukraine and Iran knock out refineries, triggering a global supply crunch.

Truckers in the U.S. are paying an average of $5.85 a gallon nationwide, a nearly 60% increase over the same period last year when diesel cost $3.71 a gallon. In California, diesel costs $7.70 per gallon, almost $2 a gallon more than the national average.

Diesel prices feed directly into higher inflation, said John Kilduff, partner at Again Capital. "You can do all the virtual shopping you want, it's all going to come to your house on a truck that ran on diesel fuel so there's no way around it," Kilduff told CNBC's "Morning Call."

Diesel is the fuel that is the most embedded in the economy, more than so than gasoline prices, said Bob McNally, founder of Rapidan Energy. Diesel is used "in transportation, it's in heating fuel, it's in agriculture, it's in industrial uses," McNally told CNBC's "Squawk on the Street" on August 17.

"It is the important macro fuel to watch," McNally said.

Higher prices come as Ukraine pounds Russian refineries, forcing Moscow to ban diesel exports. Refineries are also off line in the Middle East due to Iran's attacks on tankers in the Strait of Hormuz and regional energy infrastructure.

The wars have shut down refineries with about 5 million barrels per day of capacity, said Valero Chief Operating Officer Gary Simmons on the U.S. refiner's July 30 earnings call.

"Refining fundamentals are very tight and getting tighter with the issues in Russia and the Mideast," Brian Mandell, executive vice president for marketing at Philliips 66, said on that refiner's Aug. 5 earnings call.

About 8% of the diesel needed to supply global demand of 28 million barrels per day is disrupted right now, said Andy Lipow, president of Lipow Oil Associates, in an email to CNBC.

Russia's diesel export ban affects about 800,000 bpd of supply while the disruptions in the Strait of Hormuz have disrupted about 1.2 million bpd, Lipow said. Iran's Houthi allies knocked out Saudi Arabia's Jizan refinery that produces about 200,000 bpd, he said.

"Diesel is a stealth tax," Lipow said. "The higher fuel cost is passed on to the consumer in the form of higher prices for the goods and services that are delivered by truck and rail."