A rising number of trucking fleets are turning to renewable, biomass-based diesel fuels as drop-in replacements for petroleum diesel, cutting emissions without abandoning the engines and fueling systems they rely on today. Renewable diesel and biodiesel, in particular, offer fleets a practical pathway to decarbonization that maintains performance standards and fits seamlessly into existing operations.
“Renewable diesel, biodiesel and renewable natural gas are all decarbonization pathways…” The rollback of federal and state emissions rules that previously prioritized battery-electric trucks could further accelerate interest in these fuels, said Nate Springer, vice president of market development at TRC. “It absolutely helps that the national and California-based fleets’ resources are no longer solely devoted to Advanced Clean Fleet [regulations],” he added.
Many industry leaders view these fuels as more than a short-term bridge, noted Josh Tippin, vice president of fuels and energy at Penske Transportation Solutions. “There is no silver bullet to tackle this, and because we’re so entrenched with the efficiency and power of the diesel molecule, it’s really hard to replace,” he said, emphasizing the need for a multifaceted decarbonization strategy.
Penske began offering renewable diesel — also known as hydrotreated vegetable oil, or HVO — at its West Coast fueling locations three years ago, and Tippin said interest has consistently grown.
“Companies that are trying to mitigate their [carbon dioxide] and [greenhouse gas] footprint ask us where they can get the product and how they can use it more often,” he said. Penske Truck Leasing’s sites in California dispense renewable diesel exclusively, representing roughly 10% to 15% of the company’s total bulk fuel volume.
Beyond lowering GHG emissions, renewable diesel reduces particulate matter by more than 40%, carbon monoxide by over 25%, total hydrocarbons by more than 20%, and nitrogen oxides by 10%, Tippin said. Because it is chemically indistinguishable from petroleum diesel, it can be used in any diesel engine at any blend level.
“You don’t have to buy a new piece of equipment. You don’t have to change your infrastructure,” he said. “It’s one of the only products that’s truly a drop in.”
Renewable diesel production has surged over the past three to five years.
“There’s been significant investments by the energy majors in developing resources and converting refineries to develop that market,” TRC’s Springer said. “Kudos to them that supply is reaching and beginning to saturate certain markets.”
The U.S. Energy Information Administration estimates average renewable diesel production reached about 220,000 barrels per day in 2024, up from 170,000 the prior year. In its May outlook, the agency projected roughly 5% further growth this year as new capacity comes online. However, despite rising output, renewable diesel remains difficult to source outside states with low-carbon fuel standard programs.
“The problem with it is that you can’t get it,” said Matt McLelland, vice president of sustainability and innovation at Covenant Logistics. “It’s generally available throughout California, Oregon and Washington state, but when you’re outside of those states, it is a challenge.”
Renewable diesel made up about 5% of Covenant’s total fuel purchases last year. The Chattanooga-based carrier ranks No. 35 on the Transport Topics Top 100 list of the largest for-hire fleets in North America.
Production typically occurs where there is ample feedstock or strong policy incentives, with the majority of the production occurring in Gulf Coast and California. However, the transition from the $1-per-gallon biodiesel and renewable diesel blenders tax credit to the variable producers tax credit based on carbon intensity (CI) values has also influenced where feedstock flows and production occurs.
“It took away, in essence, availability outside of incentivized states,” Tippin said, noting that renewable diesel is often economical only with subsidies.
NACFE’s Mike Roeth said renewable diesel is the “easy button” when fleets can access it, but long-distance transport adds significant cost. “There are several fleets being asked to use it by their customers,” he said. “By the time they tell them that getting renewable diesel trucked in is going to cost an extra dollar or two a gallon and increase the cost of doing business, they’re not doing it.”
Making the Business Case
Economic pressures are shaping adoption decisions as well.
In April 2024, Volvo Trucks North America (VTNA) began using renewable diesel for factory-fill at its New River Valley plant in Dublin, Va., but paused the program in July due to rising costs. “We’ve temporarily paused the use of [renewable diesel] for our factory fill as part of cost-cutting measures in response to the weak truck market,” said Allison Daigle, VTNA’s public relations manager. She noted that Volvo still views the fuel as a strong low-carbon option and supports policies that expand supply and reduce cost.
Volvo also recently announced support for the use of 100% biodiesel in its FL, FE, FM, FMX, FH and FH16 models.
“Our customers are asking for solutions to reduce their carbon emissions and renewable fuels is an attractive option – it’s simply an efficient way to reduce CO2 from transport here and now”, explained Jan Hjelmgren, head of product management and quality, Volvo Trucks. “As a global truck maker, we need to cater for a wide variety of transport needs and market conditions which is why we do not only invest in new technologies, but also in solutions that decarbonize transport in the short and long term,” he added.
Penske Truck Leasing is conducting a controlled trial with one of its partners to measure renewable diesel’s performance and operational impacts. “In our own maintenance and testing, we don’t see any reason to disagree with the numbers that are published, but when you take a molecule like this, it almost has to be like-to-like every day to get that true test result,” Tippin said.
For this study, the partner fleet purchases renewable diesel exclusively from a dedicated tank while a nearly identical vehicle — same model, make, mileage, and route — runs on conventional diesel. “We are, for lack of a better term, getting as scientific as we can get,” Tippin said.
Now in its third month, the yearlong trial is expected to conclude in late 2026.
Beyond HVO, some fleets are adopting higher blends of renewable biodiesel produced from vegetable oils, animal fats, and recycled cooking grease. Covenant Logistics turned to high biodiesel blends to help a customer reduce indirect “Scope 3” supply-chain emissions, while Archer-Daniels-Midland Co. (ADM) turned to the technology to reduce its Scope 1 emissions.
“The transportation buyer I was working with needed the best bang for his buck,” McLelland said. “I presented this to him, and, ultimately, they pulled the trigger on it.”
Similarly, ADM Trucking — with 50 trucks, or roughly 10% of its fleet, operating on a 99% biodiesel blend — reports minimal cost differences compared with petroleum diesel, along with several operational advantages. “The operational differences are minimal, with more positives than negatives,” said Brandon Rick, fleet and sustainability manager for ADM Trucking.
ADM Trucking is a subsidiary of Chicago-based ADM, which ranks No. 80 on TT’s Top 100 list of private carriers.
Both Covenant and ADM are working with Optimus Technologies to expand biodiesel use. Backed by more than 125 million miles with leading commercial fleets and municipalities, Optimus has established trusted partnerships with OEMs, modification centers, and national refueling providers. Optimus’ vector fuel system enables engines to run on 100% biodiesel (B100) in a wide range of conditions.
Despite the technology’s success, warranty concerns often surface when fleets evaluate high-blend biodiesel. However, the concerns are generally unwarranted thanks to the Magnuson-Moss Warranty Act, explained Optimus CEO Colin Huwyler. “The short answer is no, it does not void the warranty,” he added.
Optimus’ bolt-on system has been integrated across major truck brands — including Volvo, Mack, International, Freightliner, Peterbilt and Kenworth — and Huwyler said the company collaborates with manufacturers to maintain warranty coverage.
International recently offered one of the clearest statements yet, confirming that “any vehicles that are upfit with the Optimus system to operate on 100% biodiesel will not have their warranties and/or extended service contracts from International Motors voided.”
Some fleets still recall earlier biodiesel challenges — especially cold-weather performance — which can cause hesitation. “Many of the biggest concerns and challenges were addressed long ago,” TRC’s Springer said. “This is not new, and the data is there about their benefits, how to manage them and use them effectively.”
Optimus’ systems use integrated heat exchangers and advanced software controls to prevent fuel gelling or filter plugging, even at temperatures as low as minus 35 degrees Fahrenheit (-35F), ensuring dependable operation in harsh climates.
For fleets considering B100, ADM’s Rick suggests beginning with a small pilot. “Focus on progress, not perfection,” he said. “Challenges will arise, but documenting and addressing them early helps ensure smoother scaling.”
As fleets gain hands-on experience with biomass-based fuels, momentum continues to grow.
“It was really [PepsiCo]’s adoption of this product that allowed me to have the confidence that we needed in order for us to put it into a proof of concept and recommend it to a customer,” McLelland said, noting PepsiCo operates more than 700 trucks on B99/B100 biodiesel.
Rick emphasized the strength of collaborative adoption. “Collaboration is key,” he said. “Coalitions of B100 users can pool fuel demand, making it attractive for retail providers to install B100 pumps at fuel islands.”
ADM, Covenant, McLeod Express, and others partnered with Pilot Flying J to do just that, launching the first public B100 fueling station at a travel center in Decatur, Illinois. Shortly after, two additional sites opened near Des Moines, Iowa, and Dallas, Texas.
Tippin added that incentives remain essential until the economics of renewable diesel and biodiesel improve. “Unfortunately, biomass feedstock costs more than crude. It costs more to refine, and then you have the logistics of it,” he said. “The biggest thing that can help this product move along is for local people in their state to reach out to their congressional leaders and ask for this product or to be subsidized enough to bring it there.”
State-based policies also help to drive the availability and affordability of biodiesel and renewable diesel. In states like Illinois, Iowa, and Missouri, state incentives provide tax breaks or eliminations when purchasing biodiesel and/or renewable diesel blends of a certain percentage.
Similarly, states like California, Oregon, and New Mexico operate successful low-carbon fuel standards that make biodiesel and renewable diesel affordable and competitive.
“By incentivizing the fuel, the industry sees signals for long-term growth and innovation. These incentives allow producers to invest the funds necessary to increase production and efficiencies, helping to lower the production costs,” explained Bailey Arnold, sustainability and outreach director for the Michigan Advanced Biofuels Coalition.
“It’s not a matter of this-or-that when it comes to decarbonization. While we’re investing in advanced technologies like electrification and hydrogen, we can simultaneously invest in a growing advanced biofuels industry that supports America’s farmers and fuel producers while lowering emissions and boosting our economy,” he added.
Adapted from an article originally shared by Transportation Topics. Additional information supplied by Optimus Technologies. Image Credit: Groen Solutions LLC