Neri Díaz thought he was ready for a crucial juncture in California’s ambitious plans, closely watched in other states and around the world, to phase out diesel-powered trucks.

His company, Harbor Pride Logistics, purchased 14 electric trucks this year to work alongside 32 diesel vehicles, in anticipation of a rule that as of Monday, diesel platforms can no longer be added to the list of vehicles approved to transport goods within and out. of California ports. But in August, the maker of Diaz’s electric vehicles, Nikola, recalled the trucks as part of a recall, saying he would return them in the first quarter of the new year.

“It’s a brand new, first-generation technology, so I knew things were going to happen, but I didn’t expect to get my 14 trucks back,” he said. “It’s a big impact on my operations.”

Road transportation, a huge source of carbon emissions, is where California’s green revolution is facing some of its biggest challenges. Electric trucks, with their huge batteries, can cost more than $400,000 and cannot make long hauls without stopping for long charging periods, which can undermine the economics of a truck fleet.

But California sees port trucking as an opportunity to take a big step forward.

The electric trucks currently on the market can travel from the ports of Los Angeles and Long Beach (the busiest container freight hub in the country) to many of the inland warehouses without stopping to charge. And cleaning up the port’s trucks could have a big impact. With some 30,000 trucks registered at ports, the introduction of green vehicles could lead to a substantial decrease in carbon emissions and particles that can cause illness in the communities through which the trucks travel.

Nancy González and her son Juan, 25, who has Down syndrome and rheumatoid arthritis, live in the Wilmington neighborhood, just north of the ports. Huge trucks coming and going from nearby truck yards roar constantly a few meters from the house.

Truck traffic became much heavier about four years ago, Gonzalez said, and he now cleans twice a day to get rid of the dirt it produces. Ms. González says she has sinus problems and that her son’s eyes started watering about two years ago.

“Nobody opens the windows,” he said in Spanish through an interpreter. “Nobody.”

California hopes its strict rules, combined with financial support (subsidies for truck purchases from state agencies can add up to $288,000 per vehicle, operators say), will help spur truckers, automakers, warehouse owners, utilities and cargo companies to make the investments necessary to create a carbon-free port trucking sector by 2035, when all diesel trucks will be banned from ports. And success at the ports could help the state meet its goal of decarbonizing all types of trucking over the next two decades and be a model for similar efforts in New York, New Jersey, Massachusetts, Oregon and Washington.

“In the long term, I’m pretty confident we’ll be able to decarbonize the heavy-duty truck sector,” said James Sallee, a professor in the department of agriculture and resource economics at the University of California, Berkeley, referring to California’s plan. “But I don’t know if the industry is prepared to overcome the various barriers that prevent rapid deployment.”

Port fleets have barely begun the transformation.

In November, 180 electric trucks, just 1 percent of the total, were registered to operate in the Port of Los Angeles. There was a single truck powered by hydrogen fuel cells and the other technology was used to power large trucks.

Some truck operators say they have stored diesel trucks and registered them at ports before Monday’s closure, although this does not appear in port statistics. In November, there were 20,083 diesel trucks with access to the Port of Los Angeles, up from 21,310 the previous year.

Large companies, with lots of money and large facilities, are in a better position to make the green transition. Mike Gallagher, a California-based executive at Maersk, the Danish shipping giant, said the company had an all-electric fleet, made up of about 85 vehicles made by Volvo and BYD, the Chinese automaker, to transport goods up to 50 miles away. of the ports. from Southern California. And he has worked with owners to install dozens of chargers in their warehouses.

“We’re way ahead of the curve,” he said.

But smaller truck fleets perform the bulk of port runs (they make up about 70 percent at the Port of Los Angeles) and will find the transition difficult. The California Truckers Association has introduced a federal lawsuit against the state’s transportation rules, including one targeting port trucks, arguing that they represent “a gross overreach that threatens the security and predictability of the nation’s freight-moving industry.”

Matt Schrap, executive director of the Harbor Trucking Association, another trade group, said the rules for harbor trucking lacked exemptions that would help smaller companies survive the transformation. Getting access to chargers is particularly difficult for smaller fleets, he said: They are expensive and truck yard owners may be reluctant to install them, forcing operators to rely on a public charging system that is just getting started. building.

“The owner says, ‘There’s not a chance in Bakersfield you’d tear up my parking lot to put a heavy load on it,’” Schrap said.

The concern exists beyond trade groups. Gallagher, the Maersk executive, said that if the clean truck rules caused serious problems for smaller operators, it could be “a significant disruption to the supply chain.”

Forum Mobility is one of several companies that believe they can help smaller fleets by building public truck charging stations and leasing electric trucks. The company has obtained permits to build a warehouse at the Port of Long Beach, expected to open next year, that can load 44 trucks. The depot will run on nine megawatts of electricity, enough to power most sports stadiums, but Forum Mobility executives say charging all of the port’s trucks would require about the amount of energy produced by Diablo Canyon, a California nuclear power plant. and thousands of chargers. .

“We need a real Manhattan Project on interconnection,” said Adam Browning, executive vice president of policy at Forum Mobility.

Chanel Parson, director of building and transportation electrification at Southern California Edison, a large electric power company, said it would help build truck charging infrastructure if state agencies streamlined permitting and expedited spending approvals. and if the transport companies communicated their charges. needs.

But he added that his company was not intimidated by the task. “There’s no concern that this is really difficult,” he said. “It’s what we do.”

Mr. Diaz, the operator whose Nikola trucks were recalled, said the trucks cost about 40 percent less to charge than diesel and that he was impressed with their performance. Even with the help of state subsidies, he estimates that electric trucks cost him up to 50 percent more than diesel models. During the recall, Nikola has been covering payments on loans Mr. Diaz took out to buy the trucks, but said he was concerned about the truck maker’s financial situation.

Steve Girsky, Nikola’s chief executive, said a new injection of capital in December showed investors believed in the company. “This will take us very far,” he said in an interview. “Everything this company has talked about will come to fruition in the fourth quarter.”

Some trucking executives say not only are they accustomed to responding to California’s increased regulations over the years, but they also believe in the environmental goals of the port trucking transition.

Rudy Díaz, president of Hight Logistics, said the new regulations had increased some of his costs as his company added drivers to its payroll and reduced its reliance on contract drivers who use its own diesel trucks.

“It’s extra headaches, extra costs,” he said. “But consumers are asking for products that are more sustainable and are willing to pay the price.”

Ana Facio Krajcer contributed with reports.