Electric Tractors Tackle Off-Highway Jobs

Tractors are moving beyond old-fashioned diesel power.

Traditionally, tractors and other equipment used on farms and construction sites rely on loud, dirty diesel engines. But, that’s starting to change. A variety of manufacturers are unveiling battery-powered machinery that is energy efficient and powerful, yet quiet and environmentally friendly.

Changing attitudes toward vehicle emission standards are guiding the evolution to electric drivetrains, as small farms focus on sustainability and large municipalities begin to require the use of zero-emission electric vehicles in state-run infrastructure projects.

An additional benefit of electrically powered equipment is a vastly quieter operating environment that enables next-generation machines to be deployed in densely populated areas or interior spaces with far less disturbances than they currently generate.

Operating more quietly extends the times and locations where heavy equipment can be used. It also makes the operator experience more pleasant, while improving communication and operating efficiency at the work site.

Another benefit of EV tractors is their ability to provide instantaneous torque and peak torque at every operating speed. In contrast, diesel-powered machines must idle their engines and ramp up until having sufficient power to lift a load.

In addition to startups such as Monarch Tractor and Solectrac, traditional industry heavyweights ranging from AGCO to Volvo Construction Equipment are investing millions of dollars to develop battery-powered machinery. Diesel engine manufacturers, such as Caterpillar, Cummins and Deutz, are also intensifying their electromobility research.

Earlier this year, Deere & Co. acquired majority ownership in Kreisel Electric Inc., a leading pioneer in the development of immersion-cooled battery technology. The Austrian company, which manufactures high-density, high-durability electric battery modules and packs for off-highway applications, recently developed a high-powered charging infrastructure platform.

“Kreisel’s battery technology can be applied across the broad portfolio of Deere products, and [its] in-market experience will benefit [us] as we ramp up our battery-electric vehicle portfolio,” says Pierre Guyot, senior vice president of John Deere Power Systems. “Building an electrified portfolio is key to John Deere’s sustainability goal of pursuing new technologies that reduce the environmental impact of new products and work toward zero emissions propulsion systems on equipment, while increasing our customers’ efficiency and productivity.”

CNH Industrial, a leading producer of agricultural and construction equipment with popular brands such as CaseIH, New Holland and Steyr, is also at the forefront of harnessing the power of electric power train technology.

Engineers at Case Construction Equipment recently developed an electric backhoe and excavator. The 580 EV backhoe is powered by a 480-volt, 90-kilowatt-hour (kWh) lithium-ion battery pack that can last up to eight hours. The CX15 EV is a 2,900-pound mini excavator powered by a 16-kilowatt (kW) electric motor and a 21.5-kWh lithium-ion battery.

“Our goal now is to further expand electrification and alternative propulsion into other product lines and markets that will also see the benefits from these advances related to sustainability and performance,” says Eric Zieser, director of the global compact equipment product line at Case Construction Equipment.

According to a recent analysis conducted by IDTechEx, the end goal for electric construction machines is all-electric systems, entirely replacing hydraulics and in their place using electric actuators and drive motors. Improving power train efficiency will also be crucial.

Almost all current electric construction machines have replaced the diesel engine with batteries and electric motors, but still employ a standard hydraulic system, which can be as little as 30 percent efficient. To tackle this issue, suppliers like Bosch Rexroth and Danfoss are developing digital hydraulic technology that improves power train efficiency and reduces energy consumption, with the result that a smaller battery can be used to deliver the same days’ work.

Peace and Quiet Enter the Work Zone

Another company at the forefront of off-highway EV machinery is Volvo Construction Equipment. Its expanding portfolio of electric excavators and wheel loaders is designed to be used in the same applications as equivalent diesel machines. They are better suited for environments where noise, exhaust emissions or vibrations are a problem today, such as indoor demolition, farming or food processing applications.

“In most sites, the lack of engine noise from electric construction machines is an advantage from a safety perspective, as it enables better communication between workers on site,” explains Ahcène Nedjimi, electrics and electronics systems lead engineer and electromobility specialist at Volvo Construction Equipment. “We started with compact machines, as that’s where demand starts. We will then move to medium, large and heavy construction equipment.”

Volvo CE’s electric equipment lineup currently includes three compact excavators—the ECR25 Electric, the ECR18 Electric and the EC18 Electric—as well as two compact wheel loaders, the L20 Electric and the L25 Electric. The machines feature a fully electric power source, but use hydraulic cylinders and pumps.

Depending on the type of application and intensity of the work cycle, users can operate the electric wheel loader for up to an eight-hour working day with one single charge. The EC18 boasts up to five hours of continuous runtime, while the ECR18 features up to four hours of runtime. In addition, the machines recover energy in all driving conditions while using the brake function of the electric drive system.

To meet durability demands and harsh operating conditions, the equipment has been successfully tested in temperatures ranging from 14 to 104 F. Last year, Volvo CE also launched an E-Worksite in Gothenburg, Sweden, to test electric machines’ specific requirements across different tasks within a demanding urban environment.

Meanwhile, an electric machine management application, which will be released this year in beta mode, will provide customers with remote information on the machines. This feature will enable users to remotely monitor a machine’s battery level, charging status and location.

“We have been pushed by our clients to move faster toward electrification,” says Nedjimi. “To do so, we have entered into a partnership with Samsung for batteries and opened new business areas to deal with charging systems to accelerate the electrification process.”

According to Nedjimi, electrification is the next step forward in the company’s ambition to reach net zero value chain greenhouse gas emissions by 2040. Volvo CE is also looking into making its own batteries, which is one of the goals of the joint-venture partnership with Samsung.

“The Go Electric project started in 2019, when we made the decision that all compact loaders and excavators must be electric; no more diesel,” explains Nedjimi. “By 2030, 30 percent of our sales should be electric.”

With an eye on the future, Volvo CE has also developed a prototype EC230 large excavator. Although the machine is not yet commercially available, it marks the first time the company has electrified a larger excavator as a customer pilot. Designed and built at Volvo’s facility in South Korea to suit a broader Asian customer base, the machine will be tested by customers in China and South Korea.

In addition to providing various EV options, Volvo CE is developing a robust recharging infrastructure. It currently offers different fast-charger options, including a 9.6-kW indoor fast charger and a 17.3-kW outdoor fast charger designed for use in the field.

“It’s very important for our [customers] to have not just the vehicle, but also the means to recharge it,” says Nedjimi. “Otherwise, it’s not sustainable for them. We’re dealing with battery recycling, as well. There’s a lot to do.” 

Planting the Seeds for the Electric Revolution

Electric-powered machinery is also slowly appearing in the agricultural equipment sector. The shift to batteries is starting in the small, low-horsepower tractor segment. But, as battery density and performance improve, the technology will eventually be adopted on larger machines.

“We have been actively developing proof-of-concept vehicles for a few years with the Fendt e100 Vario, which we are committed to bringing to market,” says Kelvin Bennett, senior vice president of engineering at AGCO Corp., which produces tractors under brands such as Challenger, Fendt, Massey Ferguson and Valtra. “It will be our first move into the electric sphere in agriculture and we absolutely see a market for it.

“We see two moves in agriculture,” notes Bennett. “One is a conversion design, basically a current tractor converted to run on electric power. That allows you to use implements, like a front- or rear-mounted attachment, without a lot of capital investment. The second stage would be a purposely designed machine with electric drives on the axles.”

The Fendt e100 sports a traditional continuously variable transmission transaxle with a battery electric motor as well as electric auxiliaries. Attachments are driven with complete hydraulics or power take-off (PTO), but can also be operated electrically at up to 150-kW at a time, which means existing equipment can be connected to the vehicle. Front-mounted devices, such as shovels, can also be driven hydraulically, electrically or by PTO.

“We have an electrification group that we work with internally that develops some modules that can be reused on other platforms,” says Bennett. “We’re building what we call long-term durability reliability; we want to make sure that they’re successful in all conditions for the amount of time it needs to be.”

Bennett also says there’s a component of manufacturing and supply chain readiness that needs to be addressed. “Handling batteries and storing batteries is different than engines, and it takes some capital infrastructure to support, both on our assembly lines and in our factories,” he points out.

Additional challenges that engineers must address are high load factors—particularly for ground engaging tractors—low idle times, and the constant presence of dust and other ambient elements.

“You’re battling the rain, you’re battling winter,” notes Bennett. “Agriculture has very seasonal applications. There’s a prime planting window and there’s a finite time where you need to be able to work through the night. Just to be able to charge these vehicles in remote areas is also a challenge.”

Fewer Components, Lower Maintenance Costs

One of the major advantages of electric agricultural and construction equipment is that batteries, motors and other components are virtually maintenance-free.

“The electrification of these kind of vehicles will lead to a large reduction in terms of maintenance costs,” says Pedro Pacheco, an analyst at Gartner Inc. “Less maintenance also means less downtime, which is extremely important.”

So far, there has been no massive push from government regulators to transition toward electric machinery, unlike the pressure the automotive industry has experienced. However, industrial equipment manufacturers will be able to adopt much of the EV technology already developed for car and truck applications.

According to AGCO’s Bennett, the automotive industry is where the component scale is, which is needed to control costs and reduce R&D investment.

“The cost of ownership for our customers is key,” explains Bennett. “There needs to be an attractive product cost unless there’s some big subsidies, which doesn’t currently exist in most places. We rely on developments in automotive partly to get the scale on a component to a place where we can get the right cost base for our customers.”

In addition to zero emissions, electric motors provide instant torque. For farm tractors, traction is key, and the extra weight of the battery becomes an advantage.

“In almost all other electric vehicles, battery weight is the biggest problem,” says Steve Heckeroth, founder and chief innovation officer at Solectrac, a startup company that has developed a line of electric utility tractors for light-duty farm and vineyard applications. “In a tractor, however, you need weight for traction. There’s not a better electric vehicle that you could make, because the battery weight is an asset instead of a problem.”

Solectrac offers several machines, starting with the e25, a compact electric tractor that can operate for three to six hours with a 22-kWh battery pack. On the other end of the spectrum is the e70N. The 70-horsepower machine, which is designed for heavy-duty operations, can operate for up to eight hours on a single charge via a 60-kWh battery.

In addition to torque, Heckeroth claims the main benefit of using electric power trains is ease of operation. That translates to lower maintenance costs, quieter operations and lower operating costs.

“There’s only one moving part in an electric motor, and there’s 300 to 400 moving parts in a diesel engine, a lot of which need to be lubricated and require [other] maintenance,” notes Heckeroth. “With an electric motor, maintenance is once in a decade, if any; it’s just two bearings.”

Solectrac’s vehicles can be recharged from an inverter that operates with an owner’s solar array. In addition, the exchangeable battery packs can serve as a power source when the utility grid fails.

“The cost of diesel fuel is going through the roof now,” Heckeroth points out. “It’s a very volatile source of energy and it’s not going to last forever. We know that it’s going to go up in cost, whereas solar electricity is the cheapest source of electricity there is right now, and it’s getting cheaper all the time.”

Making the Move to Fully Electric Vehicles

While Solectrac is moving toward fully electric operation, its machines currently use electric motors to run hydraulic pumps.

“We were trying to make the first tractors as close to the diesel versions as possible so that when drivers sit in the seat, everything is familiar and they don’t have to learn anything new,” says Heckeroth. “But, as we move forward, we’re going to be getting into more of the electric age.”

Heckeroth believes going to a pure electric setup will be much more efficient, because hydraulics are very inefficient.

“We use linear accelerators on one of the tractors, and they’re about 10 to 20 times more efficient than hydraulics, because when you’re pushing fluid through a tube, there’s a lot of friction and a lot of heat generated,” explains Heckeroth.   “With electric motors, on the other hand, with the right gearing they can be very small and lift thousands of pounds.”

One application that’s used in vineyards is a trimmer attachment applied to the front bumper to cut vines. It currently runs by hydraulic motors, requiring a large hydraulic pump with a radiator to cool it down, plus a “spaghetti bowl” of hoses going everywhere.

“We’re converting those to electric, and then we can just run a couple of wires and it does the same thing, but it’s 10 times as efficient,” says Heckeroth. “Those kinds of things are going to make a huge difference, where we can do much more with the limited amount of battery capacity that you can put on a tractor.”

“Battery durability still has its limitations, but that is improving at a very fast rate to a point that you’ll be able to use an electric power train for a very long time without having to replace them whatsoever,” adds Gartner’s Pacheco. “Durability is another key aspect to the reduction of maintenance costs and in turn, to operational advantages.”

Engineers at Doosan Bobcat Inc. have developed several types of compact machines that feature electric power trains, including the e10 and e20 mini excavators. Earlier this year, the company unveiled an all-electric compact track loader. The T7X is the first machine of its kind to fully eliminate all hydraulics and components. It provides the same power and performance associated with traditional diesel-powered machines.

The electric tractor features a 62-kW lithium-ion battery and operates with zero emissions, reduced sound levels, limited vibrations and lower daily operating costs. Its power management system is programmed to sense when loads are increasing, automatically backing off power when not needed to preserve total energy use and extend the machine’s runtime.

Traditional hydraulic components have been completely replaced with a drive system that consists of electric cylinders and electric drive motors. The machine also uses only one quart of eco-friendly coolant compared to 57 gallons of fluid in its diesel-hydraulic equivalent counterpart.

The all-electric platform enables instantaneous power and peak torque available at every operating speed. Operators no longer have to wait for the standard hydraulic system to build up power.

“We went all the way in that direction, because we didn’t think we would get anywhere near the runtime necessary if we just replaced an engine with a battery pack, [due to] the inefficiencies of the hydraulic system in general,” says Justin Odegaard, acceleration manager at Doosan Bobcat. “That was really the big push that made us go down the all-electric path rather than just electric powered.”

The company worked with two key partners on the T7X program: Green Machine, a division of Viridi Parente that makes an industry-specific ruggedized battery pack for construction equipment, and Moog Inc., which specializes in all types of power actuation.

The Green Machine battery offers up to four hours of continuous operation time and a full day of operation during intermittent use. A power management system is programmed to sense when loads are increasing, automatically backing off power when not needed. This helps preserve total energy use, extending the machine’s runtime.

Moog, a developer of motion control components and systems, supplies Doosan Bobcat with the electric actuators for the lift and tilt functions, in places where the cylinders would normally be, as well as the motors for the drivetrain itself.

“This was not [something] that we wanted to go down a path all on our own,” explains Odegaard. “We are experts in diesels and hydraulics, and electric is certainly something new for us.”

With fewer parts, components and fluid, regular maintenance and repair costs are significantly reduced, as is work time lost to maintenance and repairs.

“When you lift the cab, it’s pretty amazing looking at the difference between an electric vs. a diesel machine,” notes Odegaard. “You’ve got a couple of wires and such on the electric version vs. dozens of hoses, tube lines and valves. When you don’t have all those connection points, you don’t have the potential for hydraulic leaks, and no more threats for diesel leaks, engine oil leaks or hydraulic leaks.”

Odegaard claims that noise reduction is another key benefit. The machine is virtually silent, which means there’s no need to turn the machine off to be able to have a conversation with somebody outside the cab, and vehicle vibration has been virtually eliminated.  

“It’s almost impossible to make a perfectly smooth engine that doesn’t have any vibration with no engine and here, vibration in the machine is significantly reduced,” says Odegaard. “Those are the big things that the operator will notice.”

Doosan Bobcat engineers have also developed all-electric attachments for specific tasks, including an electrically powered auger to dig holes, an angle broom for sweeping, and a grapple to grab and hold materials. With an all-electric system, operators have more choices in how the machine acts.

“If they want it to be very quick and responsive, they can do that, or if they want to have softer controls for doing some really fine work, that’s easy to do with this system as well,” Odegaard points out.

The development team was able to design the control software based on work that had been done on diesel-hydraulic machines in the past and make adaptations.

“While the controls for the entire platform are obviously entirely new, the controls for making the lift arm and the tracks move is a tweaked version of diesel-hydraulic machine software,” explains Odegaard.

Doosan Bobcat will also be offering excavators that are battery powered but maintain a traditional hydraulic system.

“Electric is not the only thing we’re looking at,” says Odegaard. “Just like everybody else, we need to keep an eye on these alternative power technologies as they evolve. There might be other, more appealing opportunities that come down the road that make more sense than an all-electric option does.”

Odegaard also sees progress being made in the energy density of batteries, which could allow future machines to operate continuously for longer periods of time. For now, the company is concentrating on customers who see a four-hour operating window as sufficient.

“We could easily slap more batteries into this thing right now and get, six hours of runtime out of it,” notes Odegaard. “But, we’ll start with where we’re at and then go from there.

“[More and more, contractors] need to be able to meet these requirements, with carbon-neutral and green energy-type credits,” adds Odegaard. “When you have a large construction site that wants to be as green as possible, and you’ve got a contractor that wants to be able to bid within that context, they’re going to be willing to pay a price premium on the product so that they can meet those bid requirements.

“We know how fast things are going, how much current is being drawn at that time and the position of things,” says Odegaard. “From an overall machine intelligence standpoint, we can gather a lot more data, and then in turn make that operation better for an operator.”

A Tesla-Like Game-Changer Is Needed

Unlike the auto industry, where the rapid rise of Tesla, coupled with a swift shift in vehicle emissions regulations, pushed all automakers toward electric vehicles, what’s missing in the agricultural and construction industry so far is a major disruptor.

“Nobody has yet said, ‘we’re going to develop a piece of machinery that is fully focused on EV technology,’” says Gartner’s Pacheco. “That hasn’t [happened] yet in industrial machinery. Once this starts, you will see a major breakthrough in terms of vehicle costs and vehicle performance.”

“A lot of equipment manufacturers can learn from automakers, but at the same time, if you’re a leading player, your appetite for disruption is much less than that of a challenger,” warns Pacheco. “A company in that situation asks itself why it would bother with an electric vehicle strategy when it can get by extremely well with internal combustion. This is going to be the dilemma in this space.”

Doosan Bobcat’s Odegaard admits that there’s a lot of hesitation out there to invest in something like the T7X, when people know that for as long as they’ve been around, there’s been another way of doing things that they know works.

“How do you test the ground out to see if there’s going to be a market for something like this,” asks Odegaard. “We don’t anticipate that the T7X is going to take off and replace all of our diesel-hydraulic machines in the next couple of years. We have a lot to learn along the way as well. This is not 100 percent proven technology yet.

“The technology will get better,” predicts Odegaard. “Getting in early really helps us learn along the way, as well as satisfy those customers who are looking for something right now.”

Monarch Tractor Ramps Up New Assembly Plant in California

The MK-V tractor features a 55-kilowatt-hour battery and claims to deliver twice the torque of comparable diesel machines. Photo courtesy Monarch Tractor Co.

Monarch Tractor Co. is a startup firm building 40-hp electric machines designed for basic agricultural applications, such as spraying orchards and plowing vineyards. Its MK-V tractor features a 55-kilowatt-hour battery and claims to deliver twice the torque of a comparable diesel machine. The machine can also operate with or without a driver.

According to the company, it is 42 percent more efficient than traditional small farm tractors.

The compact machine features a low-torque electric motor that delivers 200 newton-meters (Nm) of torque compared to the 90 to 120 Nm of a diesel engine.

Monarch Tractor is currently ramping up production at a 56,000-square-foot facility in Livermore, CA, that is strategically located midway between Silicon Valley and the agricultural hotbeds of California’s Napa, Sonoma and Central Valleys.

The company is led by Mark Schwager, who previously served as head of Tesla Inc.’s gigafactory project. He also led the operations planning team and built the business systems for Tesla’s flagship factory in Fremont, CA. But, Monarch Tractor is taking a different approach to manufacturing than the automaker.

“We have a microfactory strategy,” says Schwager. “We see ourselves as a value-add assembly facility, because we’re purchasing most components from suppliers. Major subassemblies of our tractor, such as the battery pack, chassis and roof, will be produced by contract manufacturers.

“The electric motor is an off-the-shelf component,” explains Schwager. “We don’t have to win any races or set any new speed records. We are just operating a tractor at high efficiency. So, our motor will be an already mass-produced device.”

Monarch Tractor’s final assembly line will be housed in a former truck axle plant that the company recently acquired from Meritor Corp. Due to low production volumes, the factory will not be highly automated. However, it will use some automation for material handling applications.

“We also plan to deploy Industry 4.0 technology, such as augmented reality, to improve productivity and quality,” says Schwager. “It’s a great opportunity to make operators much more effective. Electric tractors are more complex than traditional diesel-powered machines, with more high-voltage cabling and harnesses that have to be carefully inserted and attached.”

—Austin Weber

Electric Machines Are Vital for Cleaner, Greener Construction

A variety of electric construction equipment is currently available. However, battery capacity directly affects performance. Illustration courtesy IDTechEx

Backhoes, bulldozers, excavators, scrapers, wheel loaders and other types of construction equipment are estimated to generate around 400 metric tons of carbon dioxide emissions per year, which is around 1.1 percent of global CO2 emission. Decarbonization of off-highway equipment will therefore be an important factor in efforts to limit global climate change, claims a new report by IDTechEx. With an increasing number of countries around the world committing to a net-zero carbon future, the $200 billion construction equipment industry is facing growing scrutiny of its greenhouse gas emissions.

Manufacturers have a complex challenge. They must greatly reduce their dependence on diesel fuel, which is the lifeblood of their mobile machinery, and move to lower emission technologies. At the same time, they must continue to supply the performance their customers expect, while ensuring that the total cost of ownership makes the adoption of battery-powered machines viable.

According to IDTechEx, the global electric construction machine market will be worth $105 billion by 2042. However, manufacturers still have a long way to go.

To undertake the same tasks as equivalent diesel machines, power train elements in electric construction vehicles need to be sized to deliver the same performance. This requires the motor and battery specification to be correctly dimensioned.

The key to the deployment of electric machines is understanding their typical daily duty cycle power and energy demands. As the construction industry employs a wide array of off-highway equipment, the maximum motor power requirement varies widely depending on the application and size of machine. Likewise, the total daily energy requirement is governed by the use case for the machine, with some duty cycles needing only sporadic operation during the day, while other machines run almost   continuously. Modular systems are required to optimize electric machine performance and cost.

The starting point for most OEMs is small, compact machines, such as mini excavators. Their duty-cycle requirements are relatively light, meaning the daily workday energy and power requirement can be met with a practical sized lithium-ion battery, electric motors and a well-defined charging strategy.

Critical to the deployment of electric machines will be the total cost of ownership. There is a premium on electric machines over diesel, primarily related to the cost of the large battery packs.

IDTechEx’s analysis suggests that the extra cost of an electric mini excavator could be modest enough that diesel fuel savings and reduced maintenance could largely offset the additional premium. However, for larger machines, the extra cost of electrification likely remains prohibitive, and OEMs may need significant regulatory and financial support to generate widespread demand.