Extending The Range

Energy storage helps power electric delivery vehicles.

Credit: Josh Hittleman
The Route powertrain is designed to deliver economic, environmental, and performance benefits.

If you’ve ever been stuck behind a garbage truck in traffic, you’ve probably wished that diesels were banned. Asphyxiating exhaust fumes from these big Class 8 trucks rival the grating noise created by frequent stopping. But what if the noise and the diesel fumes were largely eliminated? You might still get stuck behind them as they stop every few yards to collect refuse, but at least you wouldn’t need a gasmask and earplugs.

It’s an idea that Ian Wright, CEO of California-based Wrightspeed Inc. and one of the co-founders of Tesla, took to the transportation industry. The solution would appease more than just the average motorist; it would ameliorate commercial urban fleets. Trash trucks burn 14,000 gallons of diesel a year, he told Forbes, and go through brakes about every three months, averaging 1,000 hard stops on an average 130-mile daily route. There is ample room for improvement in those numbers. The difference could positively impact a fleet owner’s cost of ownership and operation, while radically diminishing emissions.

Wrightspeed is a power train company that retrofits a more efficient engine, torque converter, and transmission in Class 3–8 vehicles used for urban delivery and trash collection in order to reduce fuel, reduce emissions up to 80%, and provide better control over noise, brake wear, and maintenance.

“This combination of equipment is a new and innovative package,” says Arlan Purdy, product manager for the company. The package consists of an electric motor and transmission, supplemented by a gas turbine that generates energy. Batteries provide electric power to all four wheels. A regenerative braking system reduces wear on brakes and fuel consumption.

The turbine generator was well established in the jet aircraft industry, Purdy notes. “It’s not new technology. There’s no wondering if it works; it’s reliable, proven.” Rather, it’s the combination that makes Wrightspeed’s package innovative. “The integration and software is what puts it ahead in the market.”

Stop! And Go . . . And Stop
There is a lot of stopping in trash collection and urban delivery. That puts a lot of wear on brakes. “Brake wear is expensive,” observes Purdy. Braking also creates a spike of energy, especially if the operator engages an “aggressive racing approach.” Wrightspeed’s design collects the energy accumulated from braking and uses it to power the vehicle. “There is stable, reliable power in lithium brakes. We can store about 60 kW hours on a garbage truck.”

Storage capacity is limited to about 78 kW in garbage trucks, less in medium-duty trucks because the batteries aren’t large. “We use a relatively small battery,” acknowledges Purdy. It’s not an issue, he says, because advancements in battery technology allow a smaller battery to provide higher performance and extended range.

“It’s a rocket ship problem,” explains Purdy. Batteries would make up half the weight of the truck if only battery power was used. Although the batteries supply energy to the electric motor, which drives the wheels, the system works with small batteries because they can easily be recharged overnight and under braking. “It’s about being efficient. The frequency of braking recirculates energy.”

While fundamentally unchanged, batteries have experienced incremental improvements in range and size. “It took decades to invent,” states Purdy. Range remains the issue with small batteries. But with the Wrightspeed system, a gas turbine serves as a backup range extender generator when the battery runs out, then “kicking off” when not needed. “It depends on the drive cycle.” A geo-fence on the turbine ensures that it runs only in neighborhoods that allow it.

Long-range Benefits
“You don’t need energy for range,” says Purdy. “You need power.” He says his system provides “great acceleration.” Geared traction guide units eliminate the need for a clutch; software digitally controls the gears. “It’s lightweight for better power.” In fact, he adds, it’s better than ABS brakes in providing stability control and superior traction. “It’s more effective than a piston engine, considering the power-to-weight ratio.”

You also have to meet emissions standards. Diesel-powered trucks are required to add expensive control systems for diesel exhaust after-treatment, but turbines burn cleaner. “They only run as long as needed to charge the battery,” says Purdy. “When the battery is charged, it stops. There is no after-treatment needed. It’s a continuous jet of combustion.”

Fuel consumption is a big issue for Class 8 trucks. This system typically results in a 60% fuel reduction. It’s also quieter than its diesel counterpart. “It’s comparable to a vacuum cleaner,” says Purdy. It’s even “fuel-flexible and future-compatible.”

In addition to being quieter, it’s also cleaner. There is no friction brake debris. “You use the gas as a brake; it actively slows the vehicle,” elaborates Purdy. “There’s no coasting.”

Because it has only one moving part, it is less complex, with less potential for failure.

Customers
Big names are signing on. FedEx was Wrightspeed’s first customer, and Purdy says Mack is interested in the system as a factory option.

About four years ago, the city of Chicago ordered 20 custom-built heavy-duty electric-powered trash trucks from three main suppliers. The largest all-electric street vehicle fleet in the US at the time was assembled into rolling glider kits furnished by Crane Carrier Corp., according to HDT Truckinginfo, with final assembly performed by Detroit Chassis in Michigan.

Operating quietly, producing almost no emissions, each truck features 10 battery packs for a total capacity of 200 kW hours and a range of 60 miles. The batteries, which are recharged overnight and by regenerative braking, also supply energy to electric motors that power hydraulic pumps to run the compaction systems.

Although priced at about twice the cost of a new diesel-powered truck, they cut operating costs by at least 50%. Motiv Power Systems, which provided the scalable flex electric system, also built a 20-passenger shuttle bus for San Francisco that reduced operating cost to 10 cents per mile, compared with 80 cents per mile for a diesel chassis.

They also delivered 10 electric step-vans to AmeriPride to help it meets its goal of converting 20% of its Vernon, CA, fleet to zero-emissions. The vehicles, which use a Ford59 chassis, can run 80 miles on a full charge.

UPS, the largest commercial fleet in the US, was the first customer for Workhorse, a conversion company-turned chassis maker. “It’s important to get the largest customer first,” says Steve Burns, CEO and co-founder. “There’s no Consumer Reports for this.” These days, Workhorse’s customers include FedEx and “some bread companies.”

Spread the Word
There may not be a Consumer Report out yet, but word is getting around about the benefits of electric trucks. Workhorse asserts that they have the potential to provide more than $150,000 in savings over the course of the truck’s lifetime. The savings come from 400% improvement in fuel efficiency and 60% (or more) reduction in maintenance expenses.

Over the 20-year lifespan of a step van, the ROI is four years, Burns estimates. “It costs more up front, but less to maintain. The total cost of ownership is important. The premise is: does electricity pay for itself? Fleets that get poor gas mileages get a faster payback.” The company estimates improvements in fuel efficiency from 5.5 mpg to more than 26 mpge.

Stop-and-go not only contributes to low fuel mileage, it is also hard on brakes and transmissions, but Burns says the wear item with electric trucks is the battery. “We guarantee them for 8 years to replacement,” he says, calculating up to $125,000 in savings per truck because of it.

In addition to lowering the cost of operation, fuel, and maintenance, Workhorse systems reduce pollution and lead to more driver happiness. “We didn’t foresee that,” admits Burns, citing elimination of vibration, smoke, and noise as reasons for operator satisfaction. “Most trucks don’t have a lot of sound dampening. Vibration is wearing.”

A lower center of gravity is better for handling and one-pedal driving is easier on both equipment and operator. “It slows when you get off the accelerator,” explains Burns. “It’s easier to drive with one pedal.”

The drawback of the high initial cost is offset by more uptime and less pollution. Incentives for electric-powered trucks help convince some fleet owners to switch even when battery prices are high.

Credit: Josh Hittleman
Wrightspeed’s range-extended electric powertrain recycles the recycling truck.

The Evolution of the Battery
Incentives for early adopters helped momentum on electric vehicles until battery costs began to drop, but other battery issues have hindered widespread use of this technology. “The weight of the battery pack, as well as its obvious packaging requirements, has until now stymied the creation of a fully electric heavy-duty truck,” Tim Urquhart, principal analyst at IHS Automotive, told NBC News. However, he believes that the progress that has been made in terms of increased power storage and lower cost means that this option is now viable.

“Ten to fifteen years ago lithium batteries got stronger,” says Burns by way of explaining the rising interest in electric vehicles. “Nine years ago they got lighter, less expensive.”

Trucks now have aluminum bodies and better controls and software. Electric trucks are “faster than gas trucks,” says Burns. They have better motors. “They had to have transmissions when they first started; now motors are strong enough to power them.”

Workhorse uses Panasonic laptop batteries for consistency and reliability, Burns says, but also for cost. “The biggest cost is the battery, so we use a commodity cell. There are 7,000 cells in a truck.”

Those batteries provide 60 kW hours per pack. “A 20,000-pound vehicle wastes braking energy. Our telematics tell us we save 30 kW hours each day−what an average household uses daily−with regenerating brakes. We count on that for smaller batteries. It’s a balancing act; the battery must not be too big, heavy, or expensive. You need batteries that cost less, are lighter, and require less change to the infrastructure.”

The E-Gen Range Extended Model offered by Workhorse extends the range and life of the batteries with the help of an onboard generator, similar to an emergency 13-MW generator found in some passenger vehicles. It uses a TM4 motor for propulsion to achieve a 60-mile all-electric range. The 600cc BMW engine serves as a generator to replenish the kWh battery pack throughout the day, for a combined range of 150 miles.

“It’s sized appropriately,” interjects Burns, “but for long delays and holidays, [the trucks will] still burn some gas. We put it in for average usage, but on long days, we burn gas.” However, he adds, fleets are more consistent than the public, making it easier to plan for contingencies.

Same Old, Same Old?
“Fleets are predictable,” asserts Burns. Traditional users of electric vehicles that benefit the most include step-vans that conduct local pick-up and delivery. “They go about 5 mph and make a lot of stops for parcel and food delivery.” For fleets like this, “electricity pays for itself, even when gas is $2 per gallon,” he says.

According to United Nations data, more than half of the world’s population lives in cities, with projected growth reaching 70% by 2050. Urban delivery and trash pickup will only increase, providing unlimited opportunity for electric trucks.

And it’s just the start. “Batteries will get better,” insists Burns. When they do, the ROI will speed up even more.

Batteries aren’t the only area for change and improvement. Burns anticipates faster charging stations. “Things are changing; the infrastructure will come with the numbers. If there were fast chargers at gas stations, it would achieve the same purpose [as bigger, better batteries].” Someday, he envisions trucks carrying their own chargers. “We can use solar panels on the roof of depots, and we’re looking at putting panels on the roofs of trucks.”

Purdy says that regenerative electric systems are limited. “They’re not for every application. For example, they’re not good for 18-wheelers pulling up 40% power grades over long distances. It doesn’t work well at sustained highway speed.” However, Burns foresees jet engine fuels used in conjunction with electric batteries for OTR trucks one day.

Credit: Workhorse
An example of an electric delivery vehicle from
Workhorse with advanced controls and system.

“An electric engine will run forever and battery replacement costs are doing down,” continues Burns. Added to the economic benefit of electric trucks run on batteries are health advantages and positive environmental impact. “Diesel is a carcinogen; it’s bad enough when an engine is new, but it’s even worse when the engine is old and out of tune.” And, while electricity is from coal, lithium is “pretty green,” he says.

Nevertheless, it’s “hard to unseat the gas status quo,” confesses Burns. However, after pointing out that there’s been “no innovation in trucks in 50 years,” he says that “when something hasn’t changed in 50 years, it’s due.”

Nikola Motor Company debuted an innovative near-zero-emissions electric truck in December 2016 with $10 million in pre-orders. Known as the Nikola One, the vehicle promises to deliver fuel economy two to three times better than its diesel counterparts, weigh 2,000 to 3,000 pounds less, accelerate and brake faster, and produce more horsepower and torque−all in a package that weighs 18,000 to 21,000 pounds.

Nikola Motor Company projects fuel mileage of 10–15 mpg, assisted by aerodynamics and regenerative braking, to achieve 95% efficiency at half the cost per mile compared with diesel. According to Fleetcarma, the company will provide its first customers with up to 1 million miles of free fuel as an incentive.

Rather than design a completely new truck, Wrightspeed configures its system to fit the parameters of other vehicles. Knowing that heavy duty vehicles are on the road a lot, Purdy says most owners expect to replace an engine about half-way through its life. He calculates that switching to electric during a power train replacement “saves enough fuel to pay for itself in five years−three for a garbage truck.”

Similarly, Burns expects owners will “make money the first month.” He believes that “small contractors will go for it.” And once he has “reinvented the delivery truck,” he wants to leverage other platforms.

With interest worldwide, Wrightspeed is already “doing buses in New Zealand,” notes Purdy. “There are no close competitors. There are no hybrids mobilized for the job.” That could change as emissions regulations become stricter, batteries become more affordable, and new ideas on electric trucking solutions power the market.

“Storage was the only hindrance; now it’s less of an issue,” observes Burns. That opens up the market for electric-powered trucks.

References
http://www.forbes.com/sites/peterdetwiler/2015/03/04/electric-garbage-trucks-huge-energy-savings-and-they-wont-wake-you-up-in-the-morning/#668fa6564123

http://www.truckinginfo.com/article/story/2012/11/chicago-orders-electric-powered-heavy-trash-trucks.aspx

http://www.fleetcarma.com/heavy-duty-electric-trucks-fleet-future/

http://www.nbcnews.com/business/autos/if-you-think-electric-cars-save-gas-think-about-electric-n622261

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