What is the main feedstock for biodiesel production in the United States?

Soybean oil is the main feedstock for biodiesel production in the United States. It has historically supplied more than half of U.S. biodiesel feedstock in many production datasets, making it the standard answer to this question even though other materials are also important.

Biodiesel is made by chemically converting fats and oils into fatty-acid alkyl esters, commonly called fatty acid methyl esters (FAME). U.S. producers draw on the country’s large soybean-processing industry, where crushing soybeans produces both soybean meal and soybean oil. That established supply chain helps explain why soy oil is so prominent in American biodiesel.

The feedstock mix is broader than the quiz options suggest. Distillers corn oil, canola oil, animal fats, used cooking oil, and yellow grease are also used. Their shares vary with commodity prices, policy incentives, regional availability, and competition from food markets and renewable diesel plants.

This is specifically a U.S. pattern, not a worldwide rule. Rapeseed oil is especially important in parts of Europe, while palm oil is widely used in some other countries. Also, biodiesel is chemically different from renewable diesel, even though both can be made from oils and fats.