ExxonMobil’s Joliet (Channahon) Refinery is a significant Midwest gasoline and diesel refinery facility, and its September 2026 power outage and shutdown heavily contributed to regional price spikes. However, Wisconsin’s high gas and diesel prices derive from several different issues rather than any single cause. This includes global geopolitics, limited refining capacity, low stockpile inventories, crude costs, taxes and state policy.
Joliet Refinery Basics
The ExxonMobil Refinery is located about 40 miles southwest of Chicago near I-55 and the Des Plaines River. Built in 1972 and specialized for Canadian crude delivered by pipeline, it has a capacity of roughly 267,000 — 275,000 barrels per day. It produces about 11 million gallons of gasoline and diesel daily — roughly 6% of Midwest refining capacity, and a sizable share of the Wisconsin market. This Midwest region is also known as Petroleum Administration for Defense District 2 (PADD 2), as defined by the U.S. Energy Information Administration (EIA).
September 2026 Outage and Price Impact
On September 13, 2026, a ComEd power outage caused a plant-wide shutdown. Power returned that evening, but units stayed offline. Flooding issues, including a pump problem around September 17, delayed the restart. ExxonMobil confirmed the facility was fully back online by about September 26. During the roughly 13 day disruption, Midwest refinery supplies significantly dropped — with Joliet accounting for a large share of the lost capacity.
I recently spoke with Congressman Bryan Steil — he highlighted Joliet’s role in Midwest gas and diesel supply as a major reason for the September-October price hikes.
EIA Midwest data showed regular gas prices rising from about $3.89 before the outage to roughly $4.39 after the outage, and diesel from around $5.95 to $6.68.
Prices began to fall after the restart, with the Midwest dropping to $4.11 for regular gas prices by early October. However, diesel prices are lagging behind as gas stations work through the higher priced inventory they have on hand.
Wisconsin’s Fuel Supply Sources
Wisconsin has only one operable refinery — Superior Refining Company located in Superior, which is owned and operated by the Canadian company Cenovus. It produces gasoline and diesel at approximately 49,500–50,000 barrels per day, and is a major producer of asphalt. However, it is far too small to meet statewide demand.
In northern Wisconsin, fires have recently targeted Enbridge’s $1 billion Line 5 reroute project, which moves crude oil through the region to Midwest refineries. On October 12, a fire in Ashland County destroyed a drill rig and other equipment. No one was injured, but graffiti was found at the site. Enbridge described the incident as vandalism and said it was the latest in a series of fires (including ones in mid-September) that have damaged construction equipment and an office building.
The FBI and other agencies are investigating. While these attacks did not interrupt Line 5’s operations, they add to the ongoing risks to critical energy infrastructure. This compounded problems for Line 5, which had a temporary shutdown after an August spill.
Wisconsin relies heavily on products from other Midwest (PADD 2) refineries:
–BP Whiting, Indiana (~435,000 barrels per day, the largest in the Midwest region)
–WRB Refining Wood River, Illinois (~345,000 b/d)
–Koch Industries Saint Paul/Pine Bend, Minnesota (~335,000 b/d) — historically a major supplier to parts of Wisconsin and the Coulee Region via truck from the Twin Cities area
–ExxonMobil Joliet (~267,000 b/d)
–Marathon Robinson, Illinois (~253,000 b/d)
–Others in Ohio, Michigan, Kansas, etc.
Understanding the process
Crude oil is the thick, unrefined liquid fossil fuel found underground deep inside the Earth. The crude oil is transported through pipelines to refineries, where it is processed into finished goods like gasoline and diesel. The finished products then moves via barge, rail, and truck to gas stations.
Much of the crude processed at these Midwestern refineries is from Canada — oil sands and other grades are shipped through Enbridge’s pipelines from Alberta and other points in Canada to the Superior Terminal in Superior, Wisconsin. From there, it continues via outbound Enbridge pipelines south and east to Midwest refineries
Wisconsin has limited finished gasoline stockpiles at refineries/terminals to meet statewide demand and depends heavily on other refineries in the region.
The Midwest has built up enough refining capacity over the years that it can usually supply most of its own gasoline and diesel without heavily relying on fuel shipped in from the Gulf Coast or other regions.
However, a few very large refineries (like Joliet) produce a big share of the region’s fuel supply, and because that fuel moves mainly through a limited set of pipelines, the system is still vulnerable. When one major plant goes offline, or a key pipeline has a problem, this is enough to quickly dwindle supply and push prices up across multiple states, including Wisconsin.
Crude oil is typically the largest contributor to the overall price (usually ~50% or more of the retail price), followed by refining costs, distribution costs, marketing, and taxes.
The 2026 Gas Price Breakdown
Global geopolitics and refining issues: The Iran conflict and the Strait of Hormuz disruptions, Ukrainian military strikes on Russian refineries (especially diesel exports), Middle East refining limitations, and other export restrictions have disrupted global supplies. Crude oil prices have stayed higher than normal because of the ongoing risk of global conflict.
At the same time, U.S. refineries have been running near full capacity (often 95% or more), so they have little room to quickly produce more fuel. Supplies of diesel in storage have also been low. Even as some crude oil shipments have started to recover, the market for finished gasoline and diesel remains tight.
Regional disruptions: Joliet’s outage, plus maintenance projects at Whiting, and other issues occurring while inventory is low and demand is high exacerbates high prices. Midwest diesel was particularly sensitive to these problems.
Taxes and state policy: Wisconsin’s state motor fuel tax is 30.9¢/gal, plus a 2¢ petroleum inspection fee, plus the federal 18.4¢/gal (unchanged since 1993) — equals roughly 51¢ combined. Wisconsin’s Unfair Sales Act (“minimum markup law,” from the Great Depression era) requires retailers to mark up motor vehicle fuel by roughly 6% over certain costs — or — 9.18% over the average wholesale price (whichever greater).
Wisconsin Institute for Law & Liberty argues this outdated law adds tens of cents per gallon (estimates 30¢+ depending on wholesale levels). Supporters of this law see it as a way to protect small retailers from below-cost pricing. Efforts to repeal or modify it have been debated for years, but never came to fruition.
Gas and diesel prices are a multifaceted problem. Blaming any single politician or event oversimplifies the interaction of global supply, refining issues, regional outages, state and federal policies, taxes and Wisconsin’s minimum markup law.
Because refineries have been running near full capacity and sometimes delaying routine maintenance, they are more vulnerable to problems from weather, power failures, or equipment issues — any of which can quickly raise prices.
Related Story: https://heartlandpost.com/arsonists-destroy-enbridge-drill-rig-in-latest-eco-terrorist-attack-on-line-5-reroute/
