LOUISVILLE, Kentucky—When hauling goods, most of the energy that tractor-trailers use ultimately dissipates and goes to waste. Wabash is working with Purdue University to discover practical ways trailers could recover wasted energy.
The partnership is an example of how Wabash CEO Brent Yeagy called for collaboration to solve industry challenges at this year’s Wabash Ignite. The organizations will each contribute their strengths to explore waste recovery innovations.
“It comes down to leveraging each group’s unique skill set,” Nick Clinkenbeard, product manager for Wabash, told FleetOwner. “Our competency is how do you build it into a system, how do you produce it at the kind of scale that you would need to make that happen.”
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The case for trailer energy recapture
Tractor-trailers use a lot of energy to move themselves and haul goods. That spent energy is valuable, and many industry programs like Run on Less look to maximize the miles that a single dose of energy—whether from fuel combustion or electricity—can haul.
As the industry looks toward electrification and digitization, the range of that energy becomes even more valuable. As shippers and carriers look to improve their sustainability and lower emissions, recovering wasted energy becomes more important as well.
Companies are looking to maximize the range of electric batteries by reducing wasted energy and maximizing battery capacity, making BEVs a more appropriate means of locomotion for trucking.
Meanwhile, manufacturers continue to add new sources of vehicle power drain to enhance the intelligence and connectivity of tractor and trailer components.
“We’re looking at how do we reduce power consumption,” Paul Sniegocki, EVP of engineering and CTO at Clarience Technologies, said during a fireside chat at Wabash Ignite. “But at the same time, as we’re moving towards adding more and more technologies onto the vehicles, all of a sudden you have more power draw.”
While trailers are not necessarily active players in propulsion, they still contribute to much of the energy loss that fleets experience. Moving the air around the trailer introduces aerodynamic drag, while rolling the trailer over imperfect terrain introduces shocks and vibrations.
“We know there’s a lot of energy that is in the system that is, right now, going to waste,” Michael Bodey, director of technology discovery and validation for Wabash, told FleetOwner. “Some sort of inefficiency through movement, vibration—all these things that right now are not overly critical because you have such a dense fuel source with diesel."
“But as you start to move toward electrification, you don’t want to just be throwing away the energy that you’re already putting into that system," Bodey added. "You want to see if there’s a way to recoup that energy.”
The need to maximize energy use is only compounded by a lack of nationwide charging infrastructure.
“There are not as many charging spots as there are gas pumps,” Clinkenbeard said. “You want to be able to get as much energy as you can from what you’re doing on the road so that you can take that duration and extend that as far as you possibly can between those times where you have to recharge.”
Collaboration to find recoverable energy
Wabash and Purdue University are working together to discover realistic energy recovery sources for trailers.
The partners began their collaboration around mid-2024, Clinkenbeard said. Their research project is in its first phase: finding out how much energy trailers can recover.
In this first phase of the collaboration, the parties will work to quantify how much energy different kinds of recovery devices could realistically generate.
“It has to be an amount of energy that could go toward propulsion, so it needs to be in the magnitude of kilowatts,” Bodey said. “It’s our cutoff to have anything kind of significant and have a decent ROI associated with it. We’re not going for small 12-volt sort of tiny amounts; we’re looking for these large events where we can capture this wasted energy.”
Once they identify worthwhile energy sources, they will work to develop the devices for use in trailers. Wabash will help guide the development of the devices, keeping commercialization and efficiency in mind.
Some of the energy sources the parties have in mind come from braking, aerodynamic drag, wall vibrations, and suspension energy dispersion.
Regenerative braking
Regenerative braking is already commonly found in hybrids and electric passenger cars. Where normal braking converts kinetic energy into thermal energy, regenerative braking uses magnets to convert kinetic energy into electric energy. The solution reduces brake wear and improves powertrain efficiency.
In tractor-trailers, regenerative braking implemented on trailer axles could help recapture energy that would otherwise be lost as the vehicle as the vehicle slows down, such as during light braking events.
Aerodynamic energy recapture
According to a 2000 study by the Department of Energy, roughly half of a truck engine’s useful energy is used to overcome aerodynamic forces alone.
“That’s a huge area of energy that’s just getting wasted and diverted. We want to know how much of that we can grab ahold of and use,” Bodey said.
When just moving air around a vehicle requires so much expense, finding ways to recover that energy could lead to significant efficiency gains. An unobtrusive device on the trailer could use moving air to spin a turbine, generating power.
“There are places on the trailer that you have dead spots of air, where you’re not really going to impact the overall efficiency,” Bodey said. “You might be able to reroute some of that wasted air that’s just getting moved around and force it in through a new pathway.”
Sidewall vibrations
A trailer’s side panels experience some normal vibrations while hauling goods, subject to a blend of forces from both the terrain and aerodynamics. Those vibrations could be harnessed as energy with the right solution.
“That could be something like a piezoelectric material that, when it is flexed, will produce electricity,” Bodey said.
Contact microphones already harness this kind of energy with piezoelectric materials—at a much, much smaller scale.
“Now we’re talking about a 53-ft.-long wall that’s vibrating similar to that,” Clinkenbeard said.
Suspension energy recapture
Like brakes, the suspension of trailers dissipates kinetic energy without making further use of it. That energy waste is another prime opportunity for recovery.
“Instead of using just a shock that dissipates the energy, could you make that into a generator and actually capture that energy as you’re reducing the shock load?” Clinkenbeard asked.
The benefit of collaborations
Working with other organizations, including academic groups, was a key highlight of Wabash Ignite, with the 2024 theme Stronger Together.
Some of Wabash’s other exploratory partnerships include electric route simulations with Purdue University, trailer solar integration with the University of Delaware, end-of-life composite recycling with Ipco, and much more.
