How the US Strategic Petroleum Reserve avoids surface tanks by using underground salt caverns
An engineering explainer examines why the US Strategic Petroleum Reserve does not rely on the commercial standard of external floating roof tanks to hold its 714 million barrels of crude. It shows that scaling up conventional tank farms would require roughly 1,130 tanks spread across about 45,000 acres, an area comparable to Washington, D.C., while leaving the oil highly exposed to fire and attack.