LOS ANGELES (Reuters) -Amazon.com on Tuesday unveiled the first of a dozen Volvo electric big rigs it plans to deploy this year to pick up cargo from the nation's busiest container seaport in Southern California.

The e-commerce giant already has eight of those semi trucks in use at the Los Angeles/Long Beach port complex, where every so-called drayage truck must be zero-emissions by 2035.

The deployment is a first for Amazon, extending its vehicle electrification projects from ocean ports to customer doorsteps. The effort is vital to the company's push to reach net-zero carbon emissions by 2040.

So far, a little more than 1% of the 23,761 trucks that serve the Los Angeles/Long Beach port complex are zero-emission vehicles - including 201 electric rigs, Long Beach port spokesman Lee Peterson said.

"Heavy-duty trucking is a particularly difficult area to decarbonize," said Udit Madan, Amazon's vice president of worldwide operations.

The company has rolled out more than 13,500 Rivian electric cargo delivery vans across the country since 2022. The transition to electric semi trucks will be a bigger lift, because they haul heavier loads and their batteries require more intensive charging infrastructure.

"There is no playbook," said Adam Baker, vice president of global logistics for Amazon. For now, the company is gathering data on battery performance that will help determine how many trucks will be needed.

The manufacturer of Amazon's electric drayage trucks will continue working with the company and JAB Hunt, which provides drivers for the rigs, throughout the deployment, said Keith Brandis, vice president of partnerships and system solutions at Volvo Trucks North America.

"Charging infrastructure is the long pole in the tent. We have to get that right," Brandis said.

The ports, private companies and truck owners are racing to build heavy-duty chargers to support the transition to zero-emissions vehicles.

In the near term, Amazon's electric port trucks will charge at an offsite facility operated by Forum Mobility, a startup that counts Amazon's Climate Pledge fund among its early investors.

Forum Mobility this week broke ground on a Port of Long Beach high-speed charging depot that can serve 44 trucks simultaneously. Amazon is the first customer for the site, which will also be open to other drayage truckers, Forum Mobility CEO Matt LeDucq said.