While government and industry have long been experimenting with electric and hybrid-electric vehicles, JP-8 conventional fuel — with its long logistical tail — is still king on the battlefield. But technological advancements in batteries and alternative fuels could shake up the status quo.
Proponents of electric and hybrid-electric vehicles for the military say the technology can offer lower-cost power sources, greater performance and quieter, stealthier operations.
The Army — which has led the vast majority of the Defense Department’s work in electric vehicles — recently hosted an electrification forum that drew engineers, project managers, academia and industry together to discuss electric vehicles. The forum — which took place in Troy, Michigan, in November — was the second such event in 2018, said Dean Zeal McGrew, leader of the U.S. Army Tank Automotive Research, Development and Engineering Center’s powertrain electrification team.
It held detailed discussions about current developments TARDEC has made to date and how those fit into an overall electrical architecture, he said in an interview.
“We covered electrical inverters, DC-to-DC converters, power distribution, both high voltage and low voltage [and] low-voltage energy storage,” he said.
Cybersecurity was another area of interest, he added.
“That’s something that’s just not going to go away,” he said. “We know that [for] everything that we’re doing going forward, cyber has to be a thoughtful element to make sure that we’re not providing access into our systems.”
The event was the second in a series that will continue through summer 2019 and culminate in a new development strategy, McGrew noted. TARDEC intends to probe industry about a variety of topics that include power generation and high-voltage storage.
It will be a “living, breathing document that’s going to evolve over time, but we’ll at least have one that we’re ready to execute on and start a development process,” he said.
TARDEC has been working to overcome hurdles related to electric and hybrid-electric vehicle technology for 25 years, he noted.
“We’re coming out of the other side [on] … closing some of these gaps,” he said. Key ones that have been evident for some time are size and thermal limits associated with the power electronics required for mobility.
However, silicon carbide — a wide-bandgap switch that can be used in high-temperature applications — has enabled the organization to make systems smaller and withstand excess heat, he noted.
“We now have devices in hand that are working and [we] are confident that we’re going to be able to produce those units to provide the kind of power densities that we need to be able to package inside of a combat vehicle,” McGrew said.
Once TARDEC releases the strategy it plans to use other transaction authority agreements to get after new technology, he added. OTAs are intended to help cut through some of the bureaucratic red tape that often plagues the Pentagon acquisition system.
“That’s probably going to be the mechanism of choice,” he said. McGrew’s team currently uses OTAs with three different consortiums, he noted. “They’re all built for different uses and … we’re trying to exercise them. They’re a good tool.”
Andrew Holland, chief operating officer and director of programs at the American Security Project, a Washington, D.C.-based think tank, said advancements in battery technology will help make electric and hybrid-electric vehicles for the military a reality sooner than later.
“Even two years ago, I would’ve said, ‘Oh, electric vehicles are really for non-tactical applications. … The batteries are really too heavy, and I don’t think it will be in sort of combat tactical use for many, many years,’” he said.
But the landscape has changed since then, he noted.
“Batteries are getting better and cheaper, faster than people expected,” he said. New chemistries mean they will be much more energy dense and easier to charge, he added.
“That kind of takes away the issue with … the tactical problem,” he said.
Electric motors offer the military a number of advantages, including the ability to forgo a centralized engine, he said. Instead, the Army could have numerous engines, including one for each wheel.
“That allows you to spread the weight better and it allows you to be more resilient,” he said. “If you lose one engine, it’s not going to cause the whole thing to go down.”
Additionally, electric engines can provide a large amount of torque at rapid speeds.
“The ability of an electric engine to provide … on-demand torque immediately is substantially better than you can get in a diesel or gasoline engine,” he said. “It’s pretty cool to be sitting in there and just press the gas and it goes. … That’s a real tactical advantage.”
Jim Hasik, a senior fellow at George Mason University’s Center for Government Contracting, noted that electric and hybrid-electric vehicles are quieter than conventionally fueled vehicles which is a huge advantage when it comes to stealth.
“If people were rolling up in Bradleys … you knew it well in advance,” he said. However, if the military can get its electric combat vehicles to sound like “an overgrown Prius … rolling across the battlefield, at least for short distances, you hugely suppress your audible signature.”
Another benefit is onboard power, he said.
“You can operate power intensive sensors without actually having to light off a diesel engine,” he said. “You can sit quietly without emitting a great deal of heat that an infrared weapon can hone in on.”
Industry is thinking about new ways to power vehicles, including GM Defense, said David Albritton, the company’s president.
GM Defense recently unveiled a concept for a hydrogen fuel cell-powered vehicle based on the company’s commercial Silverado vehicle known as the Silverado ZH2. The system, which is still being built, will have a range of 400 miles. The move follows previous work GM did with its Colorado platform in conjunction with the Army.
“You have larger payloads, larger capability and you’re able to do different things with that platform than you could with a mid-size truck that we based the Colorado ZH2 on,” he said. “We’re migrating down that path to create a vehicle that we will be able to test and think about different usages of the platform.”
The Silverado ZH2 is still a conceptual vehicle. Albritton declined to comment on a timeline for the completion of the platform but said the company was working alongside the Army.
One of the benefits of a hydrogen fuel cell is its exportable power, he noted. The Silverado ZH2 will give users the ability to take advantage of up to 100 kilowatts of exportable power to juice up other equipment.
“If you think about operators at the pointy end of the spear, … their power source today is mostly dragging along heavy diesel engines,” Albritton said. “They have an odor.
They’re loud. It’s a very inefficient way to create power. … With our product not only can you take the vehicle and power the vehicle from point A to B, you can then export that power for a wide variety of usages.”
That could include active protection systems or directed energy weapons, he said. “You can imagine all kinds of things that require a significant amount of power on a platform to execute that mission,” he said. “You can do that without having any extraneous power sources coming into the theater.”
Additionally, for every hour of operation of a hydrogen fuel cell, two gallons of water are created, he said. With a chemical treatment, that water could be made potable.
Despite these benefits, the Army is unlikely to start pulling diesel engines out of M1 Abrams tanks, Holland said. However, future heavy vehicles in the service’s inventory will likely be substantially different and at least partially electric powered. That technology could start to be fielded in a decade.
And while progress is being made in battery technology it is unlikely that advancements will grow exponentially in a short amount of time like computing power as predicted by Moore’s Law, he said.
“So long as we’re on lithium-ion batteries, I think it will be … just general linear changes,” he said. “The nature of chemistry and energy density … prevents it from going too, too far” quickly.
While work is being done to develop electric vehicles for the military, they are generally not headline grabbing projects, he noted.
“This is a longer-term thing and the people who know about it and are working on it are excited about it, but I don’t see this being something that’s really high profile yet,” he said. Additionally, alternative energy efforts do not fit into the broader Trump administration’s narrative about energy, so White House officials are not out there touting it, he said.
Part of the challenge has to do with low oil prices, which has created less demand for electric vehicles, Holland added.
“For the military, the rational reasons to increase energy efficiency and reduce the amount of fuel used are not actually about price, they’re about tactical benefits and efficiency,” he noted. “But for policymakers, certainly it’s something they think about.”