The Weekly Fill-Up | September 28-October 2

September 28, 2026

As September comes to a close, harvest is moving forward and the energy markets are giving Sioux Valley Coop members several new developments to watch.

The latest numbers show a particularly important change here in the Midwest: regional diesel inventories fell noticeably during the most recent reporting week. Propane inventories are also continuing their seasonal decline, but exports are becoming an increasingly important part of that story. Meanwhile, the national conversation around diesel has shifted from simply discussing tight supply to debating whether limiting U.S. exports could provide relief.

For producers in eastern South Dakota, these developments are arriving just as fuel, propane, and lubricant needs become increasingly tied to actual harvest activity.

Midwest Diesel Inventories Drop

The latest diesel numbers deserve attention.

U.S. distillate inventories, which include diesel and heating oil, declined slightly from approximately 107.9 million barrels on September 11 to 107.4 million barrels on September 18.

Nationally, that isn’t an especially dramatic weekly move.

The Midwest tells a different story.

Regional distillate inventories fell from approximately 28.8 million barrels to 27.2 million barrels in just one week, a decline of roughly 1.6 million barrels.

For Sioux Valley Coop members, that regional movement is more immediately relevant than the national number because we’re entering a period of increased agricultural diesel consumption across the Midwest.

Harvest was already 13% complete nationally as of September 20, according to USDA. As more combines enter fields, the fuel requirement extends well beyond the combine itself. Tractors, grain carts, semis, farm trucks, elevators, and other support equipment all contribute to seasonal diesel consumption.

The latest Midwest inventory decline doesn’t mean fuel is unavailable. It does reinforce why maintaining adequate bulk storage and communicating expected needs is valuable during harvest.

Diesel Has Become a National Policy Conversation

There’s another development this week that shows just how unusual the diesel market has become.

The federal government has been considering ways to increase the amount of diesel remaining in the United States, including discussions about restrictions on diesel exports.

Reuters reported that U.S. officials have discussed both a temporary export ban and voluntary export reductions by refiners. Analysts have cautioned, however, that restricting exports could create unintended consequences. Refiners produce gasoline, diesel, jet fuel, and other products simultaneously, so changing the economics of one product can influence refinery operations and the supply of others.

This debate matters for agricultural customers even though it is taking place far from South Dakota.

The United States isn’t operating an isolated fuel market. Domestic refineries supply both U.S. customers and international buyers. When global diesel supplies become tight, overseas demand competes for U.S.-produced fuel.

For SVC members, the important point isn’t trying to predict what Washington will decide. It’s recognizing that the diesel market remains tight enough that policymakers, refiners, and fuel buyers are actively looking for ways to increase domestic availability.

Propane Supply Is Strong, But Exports Are Pulling Hard

Propane inventories continued their seasonal decline in the latest EIA report.

National propane and propylene inventories fell from approximately 109.1 million barrels on September 11 to 107.9 million barrels on September 18.

Midwest inventories also declined slightly, from approximately 26.3 million to 26.1 million barrels.

Those levels still represent a substantial supply cushion. The more interesting development this week is what’s happening to U.S. propane exports.

Exports reached approximately 2.47 million barrels per day during the week ending September 18, more than double the five-year median for the same period.

That’s important because U.S. propane isn’t reserved exclusively for American heating and agricultural customers. The United States is a major supplier to international markets, meaning strong overseas demand can pull gallons out of domestic supply even before winter heating demand reaches its peak.

That doesn’t mean propane customers should expect a shortage. Current inventories remain healthy.

It does mean that strong inventory numbers shouldn’t be viewed in isolation. Grain drying, winter weather, exports, production, and transportation will all determine how quickly those stocks decline from here.

Grain Drying Is Becoming Less Theoretical

Throughout August and early September, grain-drying demand was something we were preparing for.

We’re now reaching the point where it can become an actual draw on propane supply.

USDA currently estimates South Dakota will harvest approximately 5.84 million acres of corn for grain, producing around 846.8 million bushels.

The amount of propane required to handle that crop will vary dramatically depending on moisture.

A stretch of warm, dry weather can allow corn to continue drying naturally in the field. If harvest accelerates before moisture levels fall, more of that drying has to happen mechanically.

For customers expecting grain-drying demand, communicating anticipated propane needs becomes increasingly useful as harvest progresses.

Propane contracting also remains relevant for customers looking beyond harvest toward winter heating. SVC’s contract options provide different ways to establish greater predictability around a known future expense rather than leaving the entire season exposed to changing market prices.

Bulk Oil: Don’t Let Harvest Hours Sneak Up on You

By late September, equipment maintenance begins entering a different phase.

Pre-harvest maintenance may already be complete, but the hours accumulating on combines, tractors, trucks, and other equipment are bringing the next service intervals closer.

This is when keeping track of lubricant inventory becomes particularly useful.

Check bulk engine oil levels, hydraulic fluids, gear oils, and grease against the service work you expect to complete during harvest. A machine that runs long days can accumulate enough hours for another oil or hydraulic service much sooner than expected.

Sioux Valley Coop’s September bulk oil promotion is also nearing its end. Customers can currently save more than $1 per gallon on delivered bulk oil, making this the final opportunity to take advantage of the promotion before September ends.

For operations that know they’ll use the product, replenishing now can help combine a current savings opportunity with preparation for the maintenance that will come as harvest hours accumulate.

What Changes as We Enter October?

October will bring a different energy environment than the one we saw at the beginning of September.

Harvest activity will be much further along. Midwest diesel demand will continue responding to agricultural activity. Propane inventories will increasingly face both grain-drying and heating demand. And cooler temperatures will begin shifting the energy conversation toward winter.

At the same time, exports remain an important wildcard for both diesel and propane.

That makes this a good point in the season for Sioux Valley Coop members to reassess rather than simply rely on the plans made before harvest.

Look at how quickly bulk diesel is actually being consumed. Compare current fuel inventory with the acres still left to harvest. Watch crop moisture and grain-drying requirements. Review propane needs for the remainder of fall and winter. Check how quickly lubricant inventory is being used as equipment accumulates hours.

The market picture can change considerably over the course of harvest.

Knowing what is happening nationally is useful. Knowing what is happening inside your own tanks, equipment, and operation is what turns that information into a plan.

Sources

U.S. Energy Information Administration (EIA) – Weekly Petroleum Status Report, September 23, 2026
U.S. Energy Information Administration (EIA) – U.S. and Midwest Distillate Fuel Oil Stocks, week ending September 18, 2026
U.S. Energy Information Administration (EIA) – U.S. and Midwest Propane/Propylene Stocks, week ending September 18, 2026
U.S. Energy Information Administration (EIA) – Midwest Propane Stocks, September 2026
USDA National Agricultural Statistics Service (NASS) – 2026 South Dakota Agriculture Overview
USDA NASS – Crop Progress Report, September 21, 2026
Reuters – U.S. Diesel Export Restrictions and Global Fuel Market Analysis, September 22–25, 2026
U.S. Energy Information Administration / Industry Market Data – U.S. Propane Export Activity, week ending September 18, 2026