Biodiesel is a clean-burning alternative fuel, produced from domestic renewable resources. Biodiesel contains no petroleum, but it can be blended at any level with petroleum diesel fuel to create a biodiesel blend and it can be used in compression-ignition (diesel) engines with little or no modifications. Biodiesel refers to the pure fuel before blending with diesel fuel. Biodiesel blends are denoted as “BXX,” with “XX” representing the percentage of biodiesel contained in the blend (i.e., B20 is 20% biodiesel, 80% petroleum diesel fuel).

The Department of Defense (DoD) does not currently authorize B20 use in Tactical Fleets. The objective of this project was to demonstrate and validate the use of B20 in tactical vehicles by addressing users’ concerns as stated in the March 2006 Position Statement written by the Tri-Service Petroleum, Oil, Lubricant (POL) Users Group, which is comprised of representatives from the Army, Navy, and Air Force.

In this project, Naval Facilities Engineering and Expeditionary Warfare Center (NAVFAC EXWC) investigated biodiesel as a usable green technology in military ground tactical vehicles. The project analyzed and compared fuel samples and oil samples from vehicles using biofuels, specifically a B20 blend, against vehicles using standard petroleum diesel or jet propulsion grade 8 (JP-8) fuels, located at five military facilities across the United States. Oil analysis data was received from U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC) and fuel analysis was conducted by Concurrent Technologies Corporation (CTC).

Three types of fuel samples were collected and analyzed. The first type - delivery samples - was taken from any new shipment of fuel to the test location. At some locations, the initial storage tank fill was the only delivery sample taken for that location. The delivery samples received more extensive testing than the other samples in order to assess the quality of the fuel against the B20 specification. The second type of sample collected was the storage tank or nozzle sample. These samples were taken on a monthly basis from the storage tank, generally through the nozzle that was used to fill the vehicle fuel tank. The third type was the vehicle tank sample. This sample was also taken on a monthly basis, directly from the test vehicle’s fuel tank. Engine oil was also sampled on a monthly basis. Engine oil analysis data included measurements according to the procedures outlined in the Joint Oil Analysis Program (JOAP) Manual. Testing results for both fuel and oil samples, and weather data from each location, were loaded into a database for project team and stakeholder access and review. Each location was requested to report any unscheduled maintenance.

During this demonstration, Medium Tactical Vehicle Replacement (MTVR) or 7-Ton Trucks, High Mobility Multipurpose Wheeled Vehicles (HMMWV) (also known as HUMVEES), Tractor, Rubber Tired, Articulated Steering, Multi-Purpose (TRAM), and 2 of the 3 vehicles at Moody Air Force Base (AFB) (2008 Bobtail and a Refueler Truck) did not experience maintenance breakdowns. One vehicle at Moody AFB, a 1997 Bobtail, needed its fuel tank cleaned and the fuel sending unit rebuilt and cleaned at the end of the demonstration due to fuel breakdown.

The data gathered by this demonstration validates the March 2006 Tri-Service Biodiesel Position Paper, although it has been demonstrated that under certain circumstances (higher Rancimat, high vehicle usage) vehicles running on B20 did not have vehicle maintenance issues that were different than vehicles running on JP-8. The Tri-Service POL membership and Defense Logistics Agency (DLA) Energy have also stated that increasing the oxidative requirement for biodiesel is not feasible and limiting the use of B20 to a limited number of Continental United States (CONUS) operations is logistically impossible. Another important fact to consider is that Original Equipment Manufacturers (OEM) will not honor warranties on engine breakdowns for vehicles running on biodiesel blends above 5%, so even if the engine breakdown cannot be directly tied to the use of B20, warranties on DoD vehicles will be voided due to use of B20.

Blanket approval for the use of B20 in all tactical vehicles would not be advised because the potential for problems over and above those typically encountered with petroleum fuels is higher with the use of biodiesel. The annual fuel savings and diverted oil-based fuel only make a tiny impact on overall DoD fuel usage, and the fuel cost savings are quickly negated by a small percentage of vehicles having maintenance issues.

The maximum annual DoD fuel cost saving for switching from JP-8 to B20 is calculated to be $3,385,051, and the amount of fuel diverted from oil-based to renewable is 5,207,771 gallons. The overall impact to DoD would be less than 1% of the total use of JP-8 in DoD. Also, any cost saving derived from the difference in fuel cost between B20 and JP-8 can be quickly consumed by maintenance costs.

To reduce maintenance cost issues, a conversion from JP-8 to B20 in ground tactical fleets requires adding requirements to the current American Society for Testing and Materials International (ASTM) D7467 B20 specification to improve the fuel quality. Adding requirements may not be possible under the current acquisition process and would raise the cost of B20. This additional cost would probably negate any cost savings calculated using the current acquisition process.

B20 should only be used in CONUS training operations that run continuously, so that B20 is not left in storage and vehicle tanks for more than one month. These additional requirements will be difficult and according to the DoD POL Users Group, non-implementable, but necessary to reduce the occurrences of maintenance issues if DoD activities decide to implement B20 in tactical fleets.