Report: US Army should incorporate diesel, biodiesel as primary battlefield energies

Photo: National Academies of Sciences, Engineering, and Medicine

In addition to jet propellant 8 (JP8), the U.S. Army should incorporate the use of diesel and renewable biodiesel as the primary sources of energy brought to the battlefield through 2035 to maximize warfighting capabilities, says a new report from the National Academies of Sciences, Engineering, and Medicine. Additionally, all-electric ground combat vehicles and tactical supply vehicles are not practical in the foreseeable future, according to Powering the U.S. Army of the Future.

In making its recommendations, the committee that wrote the report analyzed the power needs of dismounted soldiers, existing vehicles (manned and unmanned), and forward operating bases. It also accounted for technological innovations regarding energy storage, power conversion, and fuel efficiency currently under development that are expected to be in service in 2035. The committee placed a heavy focus on the needs of an armored brigade combat team, a critical element for high-intensity combat in future multidomain operations.

“Since World War II, the Army is using approximately 20 times more energy per soldier, while reducing the number of soldiers deployed,” said committee co-chair John Koszewnik, retired chief technical officer for Achates Power. “This general direction will likely continue in the future and highlights the importance of energy supply and management.”

Despite the Army’s preference to rely on a single fuel to be used across all ground vehicles, generators, and turbine-powered aircraft, the report notes that using diesel, biodiesel, and JP8 would provide multiple benefits. Certain fuels would be preferable depending on environmental conditions and whether it is wartime or peacetime. During wartime, use of diesel rather than JP8 would allow for fewer trucks supplying fuel to the battlefield due to its higher volumetric energy density and more likely local availability. JP8 at times would be preferred for its cold weather properties and compatibility with aircraft, and during peacetime, biodiesel would be the preferred fuel to address environmental concerns associated with the continued use of fossil fuels. Ongoing development of technologies would allow ground vehicles and generators to operate seamlessly between diesel, biodiesel, and JP8.

While all-electric vehicles have a promising future in the consumer and commercial industries, the committee deemed ground combat and tactical supply vehicles that rely solely on battery power as impractical for battlefield use now and in the foreseeable future. Even accounting for reasonable advances in battery energy density by 2035, it would not be able to offset their weight and size disadvantages compared with internal combustion engine (ICE) or fuel cell vehicles. Even more challenging, recharging such vehicles in a short amount of time would require extremely large quantities of electric power that will not be available on the battlefield, even with the mobile nuclear power plants now under development.

However, the report notes, hybrid technologies using ICEs, generators, power electronics, and battery storage are an encouraging option, on which the Army has already initiated work. In total, actions recommended in the report would result in a projected 32 percent reduction in the fuel needed to be transported to the field and are based largely on technology that is available today.

The committee found many other opportunities that may further enhance Army energy capabilities despite the uncertain environments and situations of warfare. Some of these options include zinc-based battery chemistries that provide greater energy density and are safer on the battlefield than lithium-ion batteries; solid oxide and proton exchange membrane fuel cells; a variety of microgrid concepts; emerging technology to generate hydrogen on the battlefield; radioisotopic generators; and thermophotovoltaic fuel powered devices.

The report also states that while wind, hydro, large-scale solar, waste recovery, or small nuclear power plants would be impractical to use on the battlefield, they may be appropriate for semi-stationary bases.

The committee concluded that future studies of the Army’s power and energy options would benefit greatly from tabletop and digital war-gaming exercises using a series of detailed battlefield scenarios against which the various alternatives could be evaluated.

The study—undertaken by the Committee on Powering the U.S. Army of the Future—was sponsored by the U.S. Department of Defense. The National Academies are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine. They operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln.