It’s a first for a U.S. Navy ship: running on 100% renewable fuel, that is.

As a part of the Navy’s MILSPEC qualification program, the Naval Surface Warfare Center, Port Hueneme Division's (NSWC PHD) Self Defense Test Ship (SDTS), ex-USS Paul F. Foster, formerly a Spruance-class destroyer decommissioned in 2003, operated on 100% drop-in renewable diesel fuel in final-phase testing of the alternative fuel.

ReadiDiesel, developed by Applied Research Associates (ARA) and Chevron Lummus Global as a drop-in replacement for petroleum-based F-76 marine diesel, is a 100% renewable biofuel. The renewable diesel fuel powered the SDTS’ General Electric LM-2500 gas-turbine engine and a Rolls Royce 501 K-17 gas-turbine generator.

One critical advantage appears to be that ReadiDiesel would require no modifications to the Navy’s current refueling infrastructure. According to ARA, ReadiDiesel (and its jet-fuel counterpart, ReadiJet) does not have to be segregated from conventional petroleum-based diesel fuel. The fuels can utilize existing petroleum infrastructure without the need to build additional, costly infrastructure for blending, transportation and storage.

The SDTS took on approximately 18,000 gal (68,137 L) of ReadiDiesel in San Diego, CA. The test period lasted approximately 12 hours along the Southern California coast while en route from San Diego to Port Hueneme. Navy engineers monitored the performance of the gas-turbine engines and generators while running on petroleum F-76 prior to taking on the ReadiDiesel to establish a baseline for comparison.

While operating on 100% ReadiDiesel, the ship successfully completed multiple engine starts and speed changes. There were no mechanical, operational or qualitative differences when operating on ReadiDiesel, the Navy reported.

In addition to its role as bio-diesel test mule, the ex-USS Paul F. Foster has also served as a testbed for laser systems and remote-control operations.