They’re quiet, don’t rumble like the average semi, and will decrease transportation emissions, but electric trucks pose a potential engineering problem on their way to being part of a climate solution: They’re heavy.
The batteries and other parts needed to propel green models could weigh up to 5,300 pounds more than diesel components, which is unwelcome news for the nation’s already stressed roads and bridges.
But California is moving forward, betting on legal weight limits and technology to lighten the load as it embarks on its ambitious, first-in-the-nation regulation to put hundreds of thousands of electric trucks on the road within 25 years.
“I think it’s ultimately an engineering challenge—and engineering challenges are solvable by nature,” said Tyson Eckerle, deputy director for zero emission vehicle market development in the California Governor’s Office of Business and Economic Development.
Still, as California officials focus on expanding the market and infrastructure for green cars and trucks, weight is “something we can’t lose sight of,” Eckerle said.
A National Trend
Fifteen states and the District of Columbia will collaborate to ramp up the national market for electric medium- and heavy-duty trucks, including long-haul vehicles, school buses, and box trucks.
But California is leading the way, announcing last summer that it would require manufacturers to sell more electric trucks starting in 2024. Its zero-emission rules vary by truck weight, from 5% to 9% of sales in 2024, up to 40% to 75% of sales in 2035. By 2045, the requirement is for 100% of truck sales to be electric, no matter the class.
The plan is expected to cut greenhouse gas emissions in the state by 17.8 million metric tons through 2040.
The other states, which include Colorado, Massachusetts, and Washington, set a goal of having 100% clean truck sales by 2050—with an interim goal of 30% of sales by 2030. A New York bill awaiting signature by the governor would codify a state goal of 100% medium- and heavy-duty truck zero-emission sales.
And at the federal level, President Joe Biden signed executive orders to replace 50,000 diesel transit vehicles, electrify 20% of the nation’s school bus fleet, and direct his agencies to develop a clean fleets plan for federal, state, local, and tribal governments. That includes the U.S. Postal Service, which has 230,000 vehicles.
The administration’s first priority is to make it easier for electric vehicles to be used, a Federal Highway Administration spokesman said. And he echoed California’s rationale that battery weight will be dealt with as the market evolves. “It’s not an overnight problem, but it is a factor.”
Extra Pounds on Current Models
Daimler Trucks North America has 40 early development pre-production electric trucks on the road now, gathering diagnostics and feedback from drivers and fleet managers before manufacturing begins next year, company spokesman Fred Ligouri said.
The Freightliner eM2 and eCascadia trucks weigh about 3,000 to 4,000 pounds more than Daimler’s conventional diesel trucks, mostly due to heavy batteries. The range is between 230 and 250 miles when fully charged, with maximum weight limits when carrying cargo of between 19,500 and 82,000 pounds.
They are as quiet as a Prius.
California & other states are hoping to speed up the number of electric trucks on the roads to help reduce emissions and meet climate goals. Aside from emissions cuts, battery-electric trucks are quiet, enough to make the clicking of a blinker stand out. Daimler’s Drew Pearson: pic.twitter.com/R3Sz7iAZsJ— Emily C. Dooley (@eDooleyNoted) May 14, 2021
The biggest, the class 8 eCascadia, has two battery packs, each carrying more than 25,000 cells, which are like large AA batteries packed with lithium—among the lightest of all metals—nickel, cobalt, and other compounds.
“Chemicals and materials in battery cells are densely packaged and have a good amount of mass,” said Drew Pearson, Daimler’s eM2 Innovation Fleet Lead, explaining why they’re so heavy. “There’s just a lot of cells that are very dense in material.”
But the technology keeps advancing. In fact, the batteries on Daimler’s eM2 Innovation Fleet are almost half the weight of an earlier version, Pearson said.
Quantifying the Weight Problem
Long-haul electric trucks with a range of 300 miles could be 5,328 pounds heavier than fossil-fuel versions in 2030, with technology trimming nearly 1,000 pounds by 2050, according to a study by the University of California’s Institute of Transportation Studies.
Short-haul and medium-duty box delivery trucks trucks could weigh 1,400 extra pounds if electric, it found. Based on an average market penetration, the batteries on electric trucks could collectively equal 59.3 million pounds in 2030.
But the study also estimated that added road maintenance needs like repaving because of the extra weight would be negligible, resulting in less than 1% pavement degradation.
Alternative-fuel trucks—including hydrogen fuel cell and natural gas, which are not projected to be as prevalent as electric—could increase annual costs to repair pavement damage by up to $21 million annually on California highways and up to $33 million on local roads, the report found. One-time charges to strengthen or replace bridges in the state could be $12 million, in 2018 dollars. Much of the costs would fall on local governments.
A key assumption: By the time the transition is more advanced in 2050, batteries will weigh less.
“If we had full market penetration by 2030 this would probably be an issue,” said John Harvey, one of the report authors and professor in the Department of Civil and Environmental Engineering at University of California.
A bigger issue for trucking companies, at least initially, could be the sticker price of the electric trucks themselves. A new electric semi is projected to cost $215,000 in 2030, compared to $148,000 for a diesel-powered long-hauler.
But manufacturers and advocates say the truck costs even out eventually because of lower per-mile costs of electric versus diesel, and much less maintenance over the life of the vehicle.
Poor Condition of Roads, Bridges
Last year the American Society of Civil Engineers gave the U.S. a “C-" grade on its infrastructure report card, with bridges earning a “C” and roads a “D.”
“We have old and not in great shape roads and bridges on average,” said Marie Lehman, leader of the U.S. Infrastructure Market division at GHD, a global engineering, construction, and architecture firm. “When you take a tired road and put more load on it, it’s a problem.”
More than half of the nation’s 618,000 bridges are rated fair or poor, with 8% deemed structurally deficient. And 40% of roads are in poor condition, said Lehman, who is the American Society of Civil Engineers’ treasurer.
More weight can cause potholes and cracks, water penetration and road deterioration, while extra pounds on bridges can stress the structure.
“We have to begin upgrading the standards for roads and bridges so the new ones can handle the weight,” Lehman said.
But states also may need to lower allowable weight limits on structurally deficient bridges.
“They are not functioning to hold the weights they were designed for,” Lehman said. “There are more bridges in fair condition than in good condition. If you don’t take care of these fair bridges, they will become poor.”
West Virginia, Iowa, and Rhode Island have the most bridges in poor condition, which means parts of the deck or structures are deteriorating or have other issues, according to the National Bridge Inventory.
Beyond Weight Reduction
Technology could go beyond just lighter batteries. For instance, adding tires and axles to the largest trucks could spread the load more evenly to reduce stress on roads and bridges.
But some jurisdictions could still be left with deciding whether to increase allowable truck weight limits, which would add to pavement stress, or see an increase in the number of trucks carrying goods, said David Orr, director of the Cornell Local Roads Program, which provides technical assistance to New York governments responsible for highway and roads.
California allows fully loaded trucks up to 80,000 pounds, and alternative fuel trucks already get a 2,000-pound waiver, allowing them to max out at 82,000 pounds, said Sergio Aceves, chief of maintenance for the California Department of Transportation. Haulers with heavier batteries may just have to factor that into their cargo loads.
“They’re probably going to go up in weight,” Aceves said. “Legally it doesn’t matter. They’re still bound by the legal code.”
Uncertainty About Impacts
In California, the state already spends $1 billion to $1.2 billion annually on pavement work, and projects that the added road maintenance costs from heavier trucks would be relatively small, but still in the millions.
But just how much damage additional weight could cause is hard to quantify nationally. Even the government says so.
A 2016 study by the Federal Highway Administration looked at different weight and axle scenarios, from the current federal maximum of 80,000 pounds up to 129,000 pounds, and predicted one-time bridge costs, pavement life-cycle changes, and other factors that would arise from heavier trucks.
Current models, data limits, and other factors “were so profound that the results could not accurately be extrapolated to confidently predict national impacts,” the study found.
The highway administration asked the Transportation Research Board to develop truck, size, and weight research needs to help frame the Transportation Department’s future research plans. That 2018 report highlighted the need to study specific pavement, bridge, and fleet changes.
Last year the House and Senate Appropriations committees ordered the highway administration to submit a research plan based on the board’s report. The highway administration didn’t respond to requests for comment about whether truck weight research has been approved despite increased attention to electrification.
Long-haul all-electric models are still years off because the range of today’s batteries would require charging stops every four or five hours, which would clash with strict road-hour limits for drivers, said Daniel Haake, chair of the Trucking Industry Research Committee at the Transportation Research Board.
California wants all medium- and heavy-duty trucks sales to be for zero-emission models by 2045. The field of models is growing but primarily for short-haul urban trips under 250 miles and bus routes. Longer hauls of 300 miles or more are still far off. Daimler’s Alexander Voets: pic.twitter.com/rbcrcU8hGf— Emily C. Dooley (@eDooleyNoted) May 14, 2021
And much of the zero-emission market is still developing, said Ram Chandrasekaran, a principal analyst with Wood Mackenzie, an energy research and consulting firm.
Beyond buses, “there’s not a lot of electric commercial vehicles on the road today,” he said.
Electric light-duty pickups, delivery, box, and bucket trucks are expected to exceed internal combustion engine vehicles in 2033, and medium-duty will lag a bit behind. But heavy-duty trucks like tractor trailers will represent about 7% of the market by 2035, he said.
Battery weights are a big issue affecting the transition with larger trucks, he noted.
“Carrying a large battery pack while you’re delivering heavy goods seems counterintuitive,” Chandrasekaran said. “They are getting lighter, but the base raw metals are still there. They aren’t going away.”
Technology ‘Going Really Fast’
Quebec-based Lion Electric Co. has 150 employees focused on battery technology and cutting as much weight as possible, said Patrick Gervais, Lion’s vice president of marketing and communications.
“Obviously batteries are heavier,” he said, the “heaviest thing on our trucks.”
The company, with offices in California, is the largest North American supplier of electric school buses, and also has trucks. The bus batteries weigh 500 pounds and the truck batteries about 1,200 pounds.
But Gervais said the company uses a lighter composite frame to help hold down overall weight. And he notes that Lion is still years away from offering long-haul trucks, which could be an advantage.
“In time the weight will go down,” Gervais said. “Technology is just going really fast.”