MARAD releases results of renewable diesel testing

By Erin Voegele | April 02, 2014

On March 28, the U.S. Department of Transportation’s Maritime Administration (MARAD) announced the results of biofuel testing completed onboard the training ship State of Michigan. The tests compared operational, vibration and air emissions differences between regular ultralow sulfur diesel (ULSD) and a 76/33 blend of ULSD and renewable diesel produced by Amyris Inc.

The study determined that the renewable diesel blend reduced air emissions without any significant difference in engine performance, fuel economy, air emission, engine vibration, underwater radiated noise, or effects on the engine itself. According to information on the study released by MARAD, testing also determined that testing of the blended fuel following seven months of storage at the lest location found there was no appreciable change in fuel composition or biological contamination.

The study results specify the evaluation included a combination of underway and pierside testing that was completed over a two week period in September 2012. While the testing was originally scheduled to be completed with a 50/50 blend of renewable diesel, a report published by MARAD indicates a shipboard valve malfunction resulted in the 67/33 blend.

As a result of the testing, MARAD’s report states it has concluded that the 67/33 blend of renewable diesel appears to be an acceptable drop-in replacement fuel ULSD on the State of Michigan and other commercial vessels that have a similar power plant. “The testing successfully demonstrated all facets of drop-in fuel performance, from fuel husbandry (loading, transferring, and supply to the engine), to comparable exhaust emission performance with no adverse equipment vibration or underwater noise impact,” said MARAD in the report.

A full copy of the report can be downloaded on The MARAD website.