Must compatibility be demonstrated for any blend of biodiesel fuel?

The requirement for demonstrating compatibility with biodiesel fuel blends is not universally mandated for all blend levels. Compatibility must be assessed primarily for specific biodiesel blends, particularly those that exceed 20% biodiesel content (generally referred to as B20 or higher). For lower blends, such as B5 or B10, compatibility concerns are typically less significant, and many conventional materials that are compatible with petroleum diesel will also be compatible with these lower biodiesel blends.

This context is crucial because biodiesel can have different properties depending on its concentration and the nature of the feedstock used to produce it. Therefore, while some blends may not necessitate specific compatibility assessments, higher blends require careful evaluation to ensure that the materials used in the storage tanks, pipes, and associated infrastructure are compatible with the biodiesel to prevent issues like fuel degradation, material swelling, and leakage.

In contrast, there are no requirements to demonstrate compatibility purely for all blends or only when additives are used. The Environmental Protection Agency (EPA) does set guidelines for certain blends, but the standard practice emphasizes the need for consideration primarily for higher blends rather than a blanket requirement for all situations.