Construction equipment is going electric. Here’s what it’s like behind the wheel.
Construction equipment is going electric. Here’s what it’s like behind the wheel.
I tested a 55,000-pound electric excavator. New ways to power off-road machines, which mostly run on diesel, could cut about 3 percent of U.S. carbon emissions.
I tested a 55,000-pound electric excavator. New ways to power off-road machines, which mostly run on diesel, could cut about 3 percent of U.S. carbon emissions.
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SHIPPENSBURG, Pa. — On a 40-acre dirt and gravel lot, I climbed into the cabin of a 55,000-pound excavator. Construction crews use these hulking machines to dig trenches for laying pipes and wires or hollowing out building foundations. I took it out for a joyride.
When I switched on the motor, there was no ignition roar and no belch of diesel fumes from a tailpipe. This machine, powered by four batteries that each are big enough to run a small electric car, came to life silently.
The quiet didn’t last. The excavator’s giant treads trundled noisily over the gravel until I reached a good spot to dig. Then I grabbed hold of two joysticks and sank the bucket arm down into the dirt to scoop out as much earth as the claw could carry. I hit a big rock. The machine momentarily pitched forward, straining to loosen it from the ground — and then the electric motor heaved the boulder and a clod of dirt into the air in a puff of dust.
When they run on diesel, the biggest pieces of construction equipment can churn through 10 or more gallons of fuel per hour, emitting as much carbon and air pollution as several cars combined. Off-road equipment, including excavators, bulldozers, cranes and tractors, create about 3 percent of U.S. carbon emissions — roughly the same as the airline industry. Making these machines carbon-free would be almost as big a step toward halting climate change as taking all commercial planes out of the sky.
Workers on an assembly line for compactors at Volvo Construction Equipment plant on June 6 in Shippensburg, Pennsylvania. (Matt McClain/The Washington Post)
It won’t be easy. Electrifying off-road vehicles presents all the same challenges as replacing gas-powered cars with EVs, including worries about charging infrastructure, battery capacity and high upfront costs — plus the added challenge of digging, pushing and lifting heavy loads for hours at a time.
“They are more difficult because most of these vehicles don’t just propel themselves, they also do work,” said Kim Stelson, a mechanical engineering professor at the University of Minnesota who studies off-road vehicles. “But if we want to solve the overall problem [of climate change], we have to solve this one.”
Freddie Ryder welds parts at the Volvo Construction Equipment plant. Electric vehicles are broadening beyond commercial passenger vehicles. (Matt McClain/The Washington Post)Despite the obstacles, electric machines are slowly starting to show up at farms and construction sites. John Deere plans to sell more than 20 models of electric and hybrid construction equipment and tractors by 2026. Construction giants Caterpillar and Komatsu are developing electric excavators and wheel loaders. Volvo Construction Equipment, which made the excavator I was driving, sells seven electric models. “Almost all the major companies are working on electric solutions,” Stelson said.
How are electric and diesel machines different?
Farm operator James St. Onge pushes cow feed with a Volvo electric loader at Molly Pitcher dairy farm on June 6 in Southampton Township, Pennsylvania. (Matt McClain/The Washington Post)Volvo’s electric machines are very similar to its diesel machines, with the exception that their engines have been swapped out for batteries. The 55,000-pound electric excavator, for instance, has 264 kilowatt-hours of battery storage — the same as nine Mini Cooper EVs, or a little more than one electric Hummer.
I drove both the electric and diesel versions of the machine, and the differences between them mirrored the differences between EVs and gas-powered cars. The electric machine idled silently and its controls were slightly more responsive than the diesel one, since its electric motor can deliver power faster than a combustion engine — similar to the way an EV can accelerate faster than a gas-powered car. But both machines pulled dirt out of the ground with the same power.
A cow manure collection area that converts the waste material to methane at Molly Pitcher dairy farm. (Matt McClain/The Washington Post)You can see the similarities on display on the assembly line at Volvo Construction Equipment’s North American headquarters in Shippensburg. Similar hulking, half-formed chassis move down the lines for both types of vehicles. But, halfway through, a huge hook hanging from the ceiling will either lower an engine or a battery pack into the machine for workers to install.
The electric machines are catching on slowly. Of the 60,000 pieces of construction equipment Volvo delivered to customers last year, 895 were electric according to the company’s annual report. The company said it aims to offer electric versions of more than a third of its models by 2030.
Where might you spot electric construction equipment?
An electric excavator outside Volvo Construction Equipment's customer center. (Matt McClain/The Washington Post)Electric machines are good for a particular kind of job site. The machines need a place to charge — which could be the same level 1, 2 or 3 chargers that EVs plug into in buildings, parking lots or charging stations. And ideally, they wouldn’t have to move heavy loads for very long shifts.
“If you have a 24-hour, round-the-clock type of [work schedule], battery electrics aren’t very practical because you can’t stop to plug in for the four or five hours that it would take to recharge it,” said Ray Gallant, vice president of sustainability and productivity services at Volvo Construction Equipment.
Volvo says it often sells or leases electric machines for job sites where it pays to limit noise and air pollution. The Toronto Zoo used one of the company’s machines to avoid upsetting animals while repairing their enclosures. Cemeteries have bought excavators to quietly dig graves without disturbing mourners. Construction crews working on busy city streets use the machines to avoid annoying the neighbors or polluting their air.
At the Molly Pitcher dairy farm five miles down the road from Volvo Construction Equipment, farmers use an electric wheel loader to move feed, clean out barn floors and help lift and maintain pumps. The farmers say it’s better for the cattle to be around quieter machinery. Plus, they can charge the battery for free because the farm generates its own electricity using a device that converts manure into power.
“The more I can use that electricity, the more profitable we are,” said Keith Jones, the farm owner.
A Volvo electric loader battery system. (Matt McClain/The Washington Post)On other job sites where electric vehicles aren’t practical, construction crews can cut their emissions by running their machines on greener fuels, such as renewable diesel made from crops or used cooking oil. California now requires all off-road equipment to run on renewable diesel.
“There, you’re getting up to a 70 percent carbon benefit relative to running a diesel fuel, so that could be a really key intermediate step,” said Tom Durbin, a faculty researcher at the Center for Environmental Research and Technology at the University of California, Riverside.
One day, crews could upgrade to machines that run on pure hydrogen, a fuel that creates zero carbon emissions — but those mainly exist as prototypes today.
By Nicolás Rivero
Lol how do you think construction sites generate electricity to charge the batteries?
You're saying this like sort of gotcha, but larger generators can be a lot more efficient than a smaller engine so even running a large diesel generator 24/7 to charge a battery is likely an improvement over a gas powered digger. Same reason powering an EV with a coal power plant is still a win over a gas car, bigger engines are more efficient.
Yeah I was aware of that as I posted it. I work on construction sites. More than anything I was highlighting how vehicles isn't the only problem.
Three ways:
- They can prioritize bringing power to the site, and do that first
- They can use a trailer with solar panels, as is currently done today for lighting and tools
- For equipment which sees limited use, simply bring it to the site already-charged
Electric equipment doesn't need to be a 100% replacement to make a big difference.
You would need a pretty big solar array to power a construction site with it. But you're headed in the right direction. Not only is it an option to use renewables to power battery-powered vehicles, but also pretty much any form of electricity generation increases in efficiency and decreases in emissions (per kilowatt generated) as it scales up. Even if you are burning the same fuel at the power plant, the emissions are going to be lower overall than the equivalent number of individual internal combustion engines because the efficiency of the power plant is much higher than an ICE. Vehicle engines are ridiculously inefficient overall and when you use a more efficient fuel like natural gas it is even more drastic of a difference.
It's also much easier to put stack controls on a power plant to capture or reduce emissions than it is to put emissions controls on all construction equipment individually. This has implications for carbon capture, which could happen right at the stack. However, there's a non-climate change benefit here as well which is that the local air quality would be greatly increased around construction sites. Currently most construction equipment does not have much in the way of emissions controls for other things like sulfur and nitrogen oxides or particulate emissions. Power plants have to meet emissions standards for all of these.
- It's not always practical to get power to a site, depending on the utility and whatever upgrades they need.
- Solar doesn't generate enough, and doesn't generate at all overnight (when plant would be charged).
- Most plant lives on site and transporting it off site to charge is just going to add to costs and likely increase pollution (you need lorries to move them).
It's a good idea, and one that's growing, but it's still niche and it will be a long time before construction sites are fully electric.
I don't remember ever seeing a construction site here in Australia which generated power using a generator. Most of them simply run a temporary power connection
I've been to so many at this point
I'm guessing you don't actually work on the sites. Generators are often in containers and not necessarily obvious, or out of the way. Depends on the site and what the job is, though.
In general, a site would prefer to have a proper connection (cheaper), but more often than not it's not available.
I see what you're saying, but it wasn't too long ago a similar sentiment was said of motorized construction and farm equipment.
Ultimately, if each piece of equipment had a viable electric alternative that would operate all day without needing a charge, it wouldn't take that smart of a bean counter to realize there were a lot of savings to be had if they started projects with an electrical charging area for the new equipment that could potentially be repurposed for customer or resident charging once the job was done.
It would become an anticipated start-up cost, similar to the transport of the equipment itself, delivery of materials, set up of portable offices and toilets and the like. Obviously this would be out of reach for a small operation, but a company that's building out row houses or shopping centres I could see making the switch.
One thing that is beneficial is efficiency of internal combustion engines tends to scale with size.
One met generator is more efficient that smaller engines on each vehicle.
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Also, a lot of small equipment isn’t being used all day. You might dig a trench, work in it all day, then fire the machine back up to fill the trench.