What are tank bottoms?

This story is about oil markets, not home energy upgrades, but here's what happened. Crude oil storage at the major hub in Cushing, Oklahoma dropped below 20 million barrels from mid-June through mid-July. Storage tanks can't actually empty completely — they need a minimum amount of oil, called "tank bottoms," to keep pumps working. The gap between total tank size ("shell capacity") and how much can actually be pumped out ("working storage capacity") is what tank bottoms account for.

When Cushing storage got this low, it affected oil prices. The price of U.S. crude (West Texas Intermediate, priced at Cushing) briefly rose above the international benchmark price (Brent crude), an unusual reversal that hadn't happened since January 2022. This suggests storage at Cushing may have gotten close to its practical minimum, creating a supply squeeze in that regional market.

None of this points to a specific action for homeowners. It's a look at how oil storage infrastructure works and a signal that a key U.S. storage hub was unusually tight this summer. If you're watching fuel or heating oil costs, tight crude storage and unusual price swings like this are sometimes an early sign of broader market pressure, but this particular report is focused on the mechanics of storage tanks rather than any near-term change in prices at the pump or for home heating fuel.