Diesel sets a record and Ohio's price jumps the most

Diesel averaged $6.5276 a gallon on 22 September, the highest national average AAA has recorded in nominal dollars. A year earlier the same reading was $3.6880. NPR reported the record on 21 September, when the average sat at $6.5107. All prices here are as of 22 September; no 23 September daily reading had been published.

The number that matters

That is $2.84 more a gallon than a year ago, a rise of 77 percent on AAA's daily series. A month earlier it was $5.5947. Three milestones landed in three weeks: on 4 September the average reached $5.85 and passed the June 2022 record of $5.8159; on 11 September it crossed $6.00 for the first time, at $6.06; on 22 September it set the current high. The 2022 comparison is in nominal dollars, so adjusted for inflation the old record is closer than it looks.

The size of the weekly move depends on who counted. AAA's own daily series is up 25.8 cents from 14 to 22 September. GasBuddy put its national average at $6.490 on 21 September, up 30.7 cents on its week. The Energy Information Administration's weekly survey, released 22 September, had on-highway diesel at $6.529 for the week ended 21 September, up 24.4 cents on the week and up $2.780 on the year. One fuel, three surveys, three windows. Each of them will tell you its own is the right one.

How the price got built

Diesel comes from the middle of the barrel, the same cut as home heating oil and jet fuel. Three products, one pool.

Crude ran above $100 in mid-September during the Iran conflict, with West Texas Intermediate at $103.23 and Brent at $108.29 on 14 September, the peak of the move. By 22 September crude had fallen to a two-week low, Brent around $98.23 and Texas crude around $93.30, after Iran signalled it could reopen the Strait of Hormuz within a week and Saudi Arabia restarted the East-West pipeline to resume exports. Diesel did not follow it down. The shortage is in distillate specifically, not in crude.

The Energy Information Administration's Weekly Petroleum Status Report has distillate stocks falling another 2.164 million barrels in the week to 18 September, running about 13 percent under the five-year average; they were 106.3 million barrels on 4 September. Strikes on Russian refineries and refinery closures here had already thinned the supply reaching that pool. Inventory is the cushion, and nobody prices a cushion until the week it is missing.

Then a regional one. ExxonMobil's Joliet, Illinois refinery, approximately 264,000 barrels a day and about 11 million gallons of gasoline and diesel a day for the Midwest, lost all site power on 13 September. Power was back by about seven that evening, but the plant stayed down for the restart after a flood disabled a pump. BP's Whiting refinery slowed in the same window.

Rystad Energy's chief economist Claudio Galimberti told Rigzone on 22 September: "Brent at $100 and diesel at $6.50 a gallon are already squeezing consumers."

Who it hits here

Ohio's average diesel was $6.8174 on 22 September, 29.0 cents above the national average and 35.3 cents above New Jersey. In the week to 21 September, Ohio posted the largest one-week state rise in the country on GasBuddy's state table, up 65.3 cents, ahead of Michigan at 64.6 and Indiana at 63.6. Against GasBuddy's own national move of 30.7 cents that week, Ohio ran about 2.1 times the national pace.

Reading the state data, the Great Lakes outages rather than the overseas supply disruptions look like what put Cleveland above the national average. GasBuddy's own framing is a regional refinery problem amplifying a distillate market already tightened by the wars. Patrick De Haan of GasBuddy said on 21 September that gasoline prices rose in virtually every state that week, led by the Great Lakes, where Michigan, Indiana, Illinois, Ohio and Wisconsin each rose more than 30 cents.

That is the increase, not the level. On the Energy Information Administration's regional numbers the West Coast is at $7.456 and California at $8.246, against the Midwest's $6.680.

New Jersey sits at $6.4648 and New York at $6.5038, both just under the national average. But the Central Atlantic district came in at $6.546 against $6.177 on the Gulf Coast. That 36.9-cent gap is what the Northeast pays for sitting at the end of the pipeline.

What it costs to move a truck

A tractor-trailer at 6 mpg now burns $1.088 of fuel a mile, against $0.615 a year ago. That is 47 cents a mile, about $470 more on a 1,000-mile run. On the federal weekly series, this week's 24.4-cent move alone added 4.1 cents a mile.

Smaller scale: a box truck at 10 mpg covering 600 miles a week burns 60 gallons. The year-over-year rise adds roughly $170 a week, about $8,860 a year, per truck.

On the federal weekly series diesel is up 74.2 percent year over year, against 77 percent on AAA's daily series, which runs a day ahead of it. Gasoline is up 41.1 percent. Diesel is climbing at nearly twice the rate of gasoline, which is why this arrives as shelf prices rather than fill-ups. Fuel surcharges follow with a lag of weeks. Nobody sends a letter explaining the new surcharge line. It shows up on the October invoice.

What to watch

The next federal weekly survey covers the week ending 28 September and is released that same Monday evening, the first read on whether the climb slowed. Whether crude stays below $100 after the Hormuz signals and the Saudi pipeline restart, and whether diesel follows it down, which it has not yet. Whether Joliet restarts, the swing factor for Ohio and Midwest prices. October's Short-Term Energy Outlook carries the Winter Fuels Outlook, which prices the heating-oil season, and heating oil is the same barrel as diesel in the region that burns the most of it. And distillate stocks: the Energy Information Administration projects them falling below 100 million barrels and staying under the five-year low through most of 2027.