For trucking fleets looking to help customers reduce emissions, one of the biggest questions is how to turn sustainability goals into everyday freight operations.

Paper Transport (PTI) and packaging manufacturer Graphic Packaging International are doing just that with eight renewable natural gas-powered trucks operating on dedicated routes between Chicago and Kalamazoo, Michigan.

The trucks, equipped with Cummins X15N natural gas engines, move paperboard and recovered fiber through Graphic Packaging’s supply chain.

"After a year of operating experience, this collaboration has provided meaningful insight into how alternative fuels can be incorporated into freight operations while maintaining the service and reliability our business and customers expect," said Domingo Amunategui, vice president of logistics at Graphic Packaging, in a news release.

Helping Shippers Reduce Scope 3 Emissions

The partnership shows how trucking companies can help customers address what are known as Scope 3 emissions.

These are emissions generated outside a company's own operations, including transportation provided by outside carriers. In other words, a trucking fleet's Scope 1 emissions are part of its customers' Scope 3 emissions.

For shippers that want to reduce their overall carbon footprint, working with motor carriers that offer lower-emission transportation can help them do that.

Graphic Packaging's broader sustainability efforts include improving logistics efficiency through alternative fuels, better network planning, and carrier partnerships.

For the RNG project, PTI is working with Clean Energy, which supplies the renewable natural gas.

RNG is produced from sources such as agricultural waste, landfills, and wastewater. Depending on its source and production process, Clean Energy says RNG can reduce life-cycle greenhouse gas emissions by as much as 90% compared with diesel, with some sources achieving negative carbon intensity.

The announcement did not provide specific emissions-reduction results for the eight-truck Graphic Packaging operation.

Paper Transport's Long History With Natural Gas

The Graphic Packaging partnership builds on more than 15 years of natural gas experience at Paper Transport.

The De Pere, Wisconsin-based carrier began investing in natural gas in 2010, initially motivated in part by volatile diesel prices.

While other fleets eventually moved away from natural gas because of equipment costs, performance limitations, and maintenance challenges, Paper Transport continued investing in the technology.

The company has now accumulated more than 87 million miles on natural gas, according to its October announcement.

Paper Transport, which operates approximately 800 heavy-duty trucks, was named one of HDT's 2026 Top Green Fleets.

In that report, the fleet described how it combines natural gas with other efficiency efforts, including network optimization, reduced empty miles, driver coaching, and equipment specifications designed to improve fuel economy.

The company's experience also illustrates the importance of matching alternative fuels to the right operation.

As PTI explained in HDT's report on lessons learned by Top Green Fleets, dedicated freight, repeatable routes, reliable volume and established fueling corridors can make alternative-fuel vehicles much easier to operate successfully.

Tesla Semi Joins the Mix

Natural gas isn't the only alternative fuel strategy Paper Transport is exploring.

In July, the company announced a partnership with Tesla to evaluate the battery-electric Tesla Semi Long Range in dedicated operations in the Chicago market.

PTI said the evaluation would help it assess how battery-electric trucks perform in its dedicated operating model, where predictable routes and consistent mileage can make it easier to plan charging and equipment utilization.

"We take a consultative approach to helping customers identify and implement the right transportation solution for their network," said PTI CEO Tyler Ellison in the July announcement.

He said the Tesla partnership expands the company's options alongside renewable natural gas and intermodal transportation.

PTI has not announced results from that evaluation.