For a long time, now, the Pentagon has been looking to land diesel-electric hybrid vehicles to improve fuel economy, reduce logistics and allow power export. But after a decade of research and development, military hybrids are still years away from production, as I describe in detail in the current National Defense Magazine:
Right now, we do not have a current hybrid program that targets fielding, says Gus Khalil, team leader of hybrid-electric research at the Armys Tank Automotive Research, Development and Engineering Center, or TARDEC.
TARDEC, a division of the Research, Development and Engineering Command, in Warren, Mich., is the militarys main research center for vehicle technologies.
Khalil and other TARDEC engineers have been developing hybrid-electric engines and testing vehicle demonstrators since 1992.
Across the Defense Department, there are around 30 hybrid-electric demonstrator vehicles in some form of testing. These demonstrators range from hybrid models of existing vehicles, such as Humvees, M-113 armored personnel carriers and M-2 Bradley infantry fighting systems, to new designs such as the Marine Corps reconnaissance, surveillance and targeting vehicle, or RST-V.
Some of these demonstrators are more promising than others. Some even offer new niche capabilities. But all have failed to achieve the combination of performance, toughness, price and utility that the military demands of its vehicles.
Motor Trend explains:
Though hybrid technology has been around for several years in passenger vehicles, adapting it for larger vehicles isn't as easy, [Oshkosh VP Gary] Schmiedel said. Military vehicles must often carry thousands of pounds of cargo -- 13 tons for the HEMTT -- and endure hills, little pavement and angles that few standard vehicles can handle. That all means engines and axles must be configured just so.
Even more daunting is the battery problem. National Defense editor Sandra Erwin reported on this as far back as 2001:
The Achilles heel of hybrid systems today, however, is the battery, [engineer William] Haris added. You need to have a source of energy to propel the electric motors. Traditionally that has been batteries. The most commonly used batteries today are lead-acid, which are the least expensive. But they also are heavier and less efficient than more advanced chemistry batteries.
A more desirable alternative would be nickel-metal-hydride batteries, which have twice the energy density of lead-acid. Energy density is the amount of energy that can be stored per pound of material. In the long-term, experts are looking at lithium-ion batteries, which have four times the energy density of lead-acid.
Where there's a will, there's a way -- technical challenges notwithstanding. There are challenges, and there are issues, but they dont seem insurmountable, Khalil told me. If someone from a program office told us they wanted something in production in two years, we would have it into production.
But despite the promise of a reduced logistics burdened resulting from great fuel efficiency, the military's enthusiasm for hybrids is cool. If not for their power export capability, the military might not be interested at all.
The bottom line is ... the tech isn't ready, and the military isn't ready to make the tech ready. So be skeptical when some hack reports that military hybrids are just around the corner.
-- David Axe
