Renewable Diesel and RNG Gain Ground as Crude Tops $110

Why are fleets switching to renewable diesel and RNG now?

Renewable diesel, high-blend biodiesel, and renewable natural gas are becoming more attractive options for fleet operators as crude oil prices climb and operating costs hit record highs. With Brent crude at $110.37 per barrel and operating costs reaching $2.26 per mile — the highest non-fuel cost on record — small fleets are looking at alternative fuels not just for environmental compliance but as a hedge against diesel price volatility.

Renewable diesel is chemically identical to petroleum diesel but made from waste fats, vegetable oils, and other biomass feedstocks. It drops into existing diesel engines without modification and delivers comparable fuel economy. High-blend biodiesel — typically B20 (20% biodiesel, 80% petroleum diesel) or higher — requires minimal engine adjustments and is widely available at truck stops in the Midwest and parts of the Southeast. Renewable natural gas, produced from landfill gas, agricultural waste, and wastewater treatment plants, runs in dedicated CNG or LNG engines and trades at a significant discount to diesel on an energy-equivalent basis in many markets.

What makes renewable fuels more attractive now than six months ago?

Three factors converged in early 2026. First, the oil price spike — Brent crude jumped 11% in the first week of May alone — widened the price gap between petroleum diesel and renewable alternatives. Renewable diesel typically trades at a small premium to conventional diesel, but federal and state incentives — including the renewed blenders' tax credit and California's Low Carbon Fuel Standard credits — can push the net cost below petroleum diesel in certain lanes. Second, manufacturing input costs hit a four-year high in April, pressuring shippers to demand cleaner supply chains and pushing some large contract customers to specify low-carbon fuel in RFPs. Third, renewable fuel production capacity expanded significantly in 2025 and early 2026, improving availability and stabilizing supply in regions where access was previously spotty.

For a small fleet running 10 trucks and burning 15,000 gallons per truck per year, a 5-cent-per-gallon net savings on renewable diesel — after incentives — translates to $7,500 annually. That figure matters when rates are climbing but not fast enough to cover the cost spike. Renewable natural gas delivers a larger per-gallon discount in some markets — as much as 50 cents per diesel-gallon-equivalent in California and parts of the Midwest — but requires upfront investment in CNG or LNG tractors, which limits adoption among fleets that can't afford new equipment.

Where renewable fuels pencil for small fleets

Renewable diesel availability is strongest in California, the Pacific Northwest, and parts of Texas, where refineries have converted petroleum units to renewable feedstocks. Neste, Chevron, and Phillips 66 all operate renewable diesel facilities on the West Coast, and truckstop chains including Pilot and Love's have added renewable diesel islands at high-volume locations. High-blend biodiesel is most accessible in the Corn Belt — Iowa, Illinois, Indiana, Minnesota — where soybean oil feedstock is abundant and state-level blending mandates create consistent supply.

Renewable natural gas infrastructure is concentrated in California, where LCFS credits make RNG the lowest-cost fuel option for fleets with CNG tractors, and in pockets of the Midwest near agricultural waste sources. A fleet running a California-to-Arizona lane with access to RNG fueling can cut fuel costs by 30% to 40% compared to diesel, but the same fleet running cross-country will struggle to find RNG stations outside the West Coast and a handful of Midwest corridors.

The operational constraint for small fleets is fueling infrastructure. A 5-truck fleet running regional routes in California can switch to renewable diesel tomorrow with no equipment changes and immediate cost savings. The same fleet running OTR will find renewable diesel availability inconsistent east of the Rockies, forcing drivers to plan fuel stops around specific truck stops or accept petroleum diesel when renewable isn't available. For RNG, the infrastructure gap is wider — fewer than 200 public-access CNG stations serve heavy-duty trucks nationwide, compared to thousands of diesel islands.

What the fuel shift means for settlement statements

Fleets adopting renewable diesel see the cost impact immediately in fuel line items, but the net savings depend on local incentives and contract terms. California fleets benefit from LCFS credits, which fuel suppliers pass through as a per-gallon discount. Federal blenders' credits — currently $1.00 per gallon for renewable diesel made from waste feedstocks — flow to the blender, not the end user, but competitive pressure among fuel retailers pushes some of that value down to the pump price. A fleet buying renewable diesel at the rack in Los Angeles might pay 10 cents per gallon more than petroleum diesel before incentives, but net 8 cents per gallon less after LCFS credits.

For biodiesel, the math is tighter. B20 typically trades within a few cents of petroleum diesel at the pump, and the federal biodiesel blenders' credit — $1.00 per gallon of pure biodiesel, so 20 cents per gallon of B20 — again accrues to the blender. Small fleets see savings only when fuel suppliers compete on price or when state-level incentives add a direct discount. In the Midwest, where biodiesel supply is abundant, B20 often costs the same as or slightly less than straight diesel. East of the Mississippi and south of the Mason-Dixon line, B20 availability drops and any price advantage disappears.

RNG delivers the largest per-gallon savings but requires the largest upfront cost. A new CNG day cab runs $30,000 to $50,000 more than a diesel equivalent, and a used CNG truck carries higher maintenance risk because the fuel system is more complex. A 10-truck fleet converting to CNG faces $300,000 to $500,000 in incremental equipment cost, which takes three to five years to recover through fuel savings even in high-incentive markets like California. For owner-operators, the payback math works only if they run dedicated lanes with consistent RNG access and can finance the equipment at favorable terms.

How long the renewable fuel window stays open

Renewable fuel economics hinge on two variables: the crude oil price and the policy environment. If Brent crude stays above $100 per barrel — as it has since late April — the price gap between diesel and renewable alternatives widens, making renewable fuels more competitive even without subsidies. If crude falls back below $80, the gap narrows and small fleets lose the cost incentive to switch unless policy incentives strengthen.

Federal tax credits for renewable diesel and biodiesel are currently authorized through 2027, but extensions are uncertain. California's LCFS program is permanent state law and continues to drive West Coast renewable fuel adoption regardless of federal policy. Other states — Oregon, Washington, and New York — have adopted or are considering similar low-carbon fuel standards, which would expand the geographic footprint where renewable fuels pencil without federal support.

Production capacity is the other variable. Renewable diesel output in the US is projected to reach 5 billion gallons annually by the end of 2026, up from 3 billion gallons in 2024. That's still less than 4% of total US diesel consumption, so supply constraints and regional price disparities will persist. Small fleets in California and the Pacific Northwest will continue to see consistent renewable diesel availability and competitive pricing. Fleets running east of the Rockies will face spottier supply and smaller cost advantages until more refineries convert or new renewable diesel plants come online in the Midwest and Southeast.

For a small fleet deciding whether to adopt renewable fuels now, the calculus is straightforward: if your lanes keep you in California or the Corn Belt and your trucks can burn renewable diesel or B20 without modification, the fuel switch pays immediately. If you run OTR or operate outside those regions, renewable fuels remain a hedge — useful when available, but not yet reliable enough to plan your fuel budget around.