The Weekly Fill-Up | August 24-28

August 24, 2026

The final full week of August is giving Sioux Valley Coop members two very different supply stories.

Diesel inventories have moved lower just as agriculture begins looking toward harvest, while propane inventories continue building at a strong pace ahead of grain drying and winter heating demand. At the same time, the global refining system remains under significant pressure, making dependable supply and advance planning increasingly important as we head toward September.

For producers, homeowners, and businesses across eastern South Dakota, this week’s markets reinforce an important point: diesel, propane, and lubricants may all come from the broader petroleum industry, but their markets can behave very differently.

Diesel Inventories Move Lower

The latest U.S. Energy Information Administration report showed U.S. distillate inventories, which include diesel fuel, falling from approximately 107.1 million barrels on August 7 to 105.6 million barrels on August 14.

The Midwest also experienced a decline, although it was much smaller. Midwest distillate stocks moved from approximately 28.6 million barrels to 28.4 million barrels during the same period.

Those changes come as U.S. refineries continue working extremely hard.

Recent market reporting shows U.S. refineries have operated above 95% utilization for more than 11 consecutive weeks, the longest stretch at that level in more than 25 years. Strong refinery output has helped keep fuel moving despite major disruptions elsewhere in the world.

That is good news for domestic availability, but there is another side to the story. When refineries are already operating near their limits, there is less unused capacity available to quickly compensate for an unexpected outage.

Global supplies of finished fuels also remain under pressure. Refinery disruptions and reduced fuel production in other parts of the world have increased the importance of U.S. refined-fuel production and exports.

For Sioux Valley Coop members, this doesn’t mean diesel is unavailable. It does mean the market is entering the weeks before harvest without an especially large supply cushion.

Now is a good time for producers to estimate harvest consumption, confirm bulk storage capacity, and make sure tanks and equipment are ready. The goal isn’t necessarily to fill every tank immediately. It is to have a fuel plan established before regional agricultural demand begins increasing.

Propane Inventories Continue Their Summer Climb

Propane provides a much more encouraging supply picture this week.

EIA data shows total U.S. propane and propylene inventories reached approximately 107 million barrels for the week ending August 14, up from about 105 million barrels the previous week.

More importantly for our region, Midwest inventories increased from approximately 25 million barrels to more than 26.1 million barrels in a single week.

That continued inventory growth gives the propane industry a substantial supply base heading toward fall.

The next question is how quickly those gallons will be needed.

As crops mature across South Dakota and the greater Corn Belt, attention will increasingly turn toward harvest moisture. A warm, dry finish to the growing season could reduce grain-drying requirements. Wetter corn coming out of the field could produce a much stronger pull on propane inventories.

Winter weather is the other major unknown. Propane supply may look strong in August, but heating demand can change the market considerably once temperatures begin falling.

That’s why propane contracting remains worth considering now.

For customers who know they will need propane this fall or winter, a contract can help provide greater budget certainty before seasonal demand becomes established. Sioux Valley Coop offers options including 100% prepay, no-money-down contracting, and consumption billing.

Contracting isn’t about knowing exactly what the market will do next. It’s about deciding whether reducing exposure to future price uncertainty makes sense for your household, farm, or business.

Bulk Oil: Think Beyond the Oil Change

As harvest maintenance gets underway, bulk oil planning should include more than simply checking whether there is enough engine oil in the shop.

Hydraulic fluid, transmission and drivetrain lubricants, gear oils, and grease can all become critical once equipment begins operating for extended hours. One overlooked product can create just as much downtime as running short on fuel.

This is particularly important for operations running several pieces of equipment with different lubricant specifications.

Before harvest begins, review what each tractor, combine, truck, auger, and support vehicle requires. Check current inventory against anticipated service intervals and make sure the correct products are available.

The lubricant market has faced some upward pressure from base-oil pricing this summer, reinforcing the value of planning purchases rather than waiting until a product is urgently needed.

For operations that use larger quantities, bulk oil can also simplify inventory management by keeping frequently used lubricants readily available throughout the season.

A Tale of Two Inventories

The most useful market comparison this week may be diesel versus propane.

National distillate inventories fell by roughly 1.5 million barrels in the latest reporting week. During that same period, propane and propylene inventories increased by more than 2 million barrels.

That doesn’t tell us exactly where prices will go, but it does show why each market requires its own strategy.

Diesel is approaching harvest with relatively tight inventories and a global refining system working extremely hard to meet demand. Propane is approaching fall with inventories continuing to build, but future grain-drying and heating demand remain unknown. Lubricants are readily available, yet maintenance requirements will become considerably more important once harvest begins.

For Sioux Valley Coop members, late August is an opportunity to use those differences to your advantage.

Review anticipated bulk fuel consumption before harvest. Consider whether propane contracting fits your budget and expected usage. Check lubricant inventory against the equipment that will soon be running long days.

Markets will change as we move into September. Having a plan in place before they do can make those changes much easier to manage.

Sources

U.S. Energy Information Administration (EIA) – Weekly Petroleum Status Report, August 19, 2026
U.S. Energy Information Administration (EIA) – U.S. and Midwest Distillate Fuel Oil Stocks, week ending August 14, 2026
U.S. Energy Information Administration (EIA) – U.S. and Midwest Propane/Propylene Stocks, week ending August 14, 2026
USDA National Agricultural Statistics Service (NASS) – South Dakota Agricultural and Crop Data, August 24, 2026
Reuters – U.S. Refinery Utilization and Global Refined-Fuel Supply Analysis, August 24, 2026
Reuters – Global Refined-Fuel and Diesel Market Analysis, August 24, 2026