The industry must sustain what it has never sustained before
In the spring of 2026, the EPA issued a renewable fuel mandate that asked the American biomass-based diesel industry to do something it had never done before — not merely grow, but surge, nearly doubling output within a year. The rule, born of climate and energy policy ambitions, set volume obligations so far beyond historical norms that even the industry's accumulated reserves could barely cover a fraction of the gap. What unfolds now is a test of whether regulatory vision and industrial reality can be reconciled before the weight of compliance falls on markets, prices, and the people who depend on them.
- The EPA's 'Set 2' rule demands D4 RIN generation leap 55–67% above 2025 levels, reaching territory the industry has never sustained — not for a month, let alone a year.
- The first quarter of 2026 has already hemorrhaged 1.18 billion gallons of compliance headroom, with January and February posting some of the weakest generation numbers in recent memory.
- A tax credit transition gutted import incentives almost overnight, removing a key supply lever precisely when the mandate needed it most.
- To close the gap, the remaining nine months of 2026 must average over 1,090 million RIN gallons monthly — a pace more than 20% above any single month ever recorded in U.S. biomass-diesel history.
- The industry now faces a three-way choice: push domestic plants to unprecedented utilization rates, revive imports under uncertain economics, or drain the RIN bank and defer the reckoning to future compliance years.
On March 27, 2026, the EPA finalized its 'Set 2' renewable fuel rule — and buried inside its pages was a demand unlike anything the biomass-based diesel sector had ever faced. The rule required between 11 and 12 billion RIN gallons of biomass-based diesel annually in 2026 and 2027, a jump of 55 to 67 percent from the 7.1 billion gallons actually generated in 2025. The increase alone dwarfed the entire surplus RIN bank the industry had built up as a buffer against hard years.
The obligation came from three converging streams: the core biomass-based diesel mandate of roughly 9 billion gallons per year, 534 million gallons in annual export retirements, and a 'D6 pull' of over 1.4 billion gallons annually — demand created when conventional ethanol supplies fell short and biomass-based diesel had to fill the void. No single one of these was new. Together, they created a requirement with no historical precedent.
The monthly math made the challenge concrete. Meeting the 2026 target would require averaging 916 million RIN gallons per month. The industry had averaged 592 million per month across all of 2025. The single highest month on record — December 2024 — reached 906 million gallons, but that spike was a one-time import surge triggered by an expiring tax credit, not evidence of durable capacity.
By spring, the early returns were sobering. January yielded 436 million gallons, February 478 million, March 649 million. The cumulative first-quarter shortfall stood at roughly 1.18 billion gallons — 11 percent of the annual requirement, gone before April. A shift from the blenders tax credit to the new 45Z clean fuel production credit had made imported biofuels ineligible for subsidy, and import volumes collapsed accordingly. The remaining nine months of 2026 would need to average nearly 1,090 million gallons monthly just to break even on the year.
Analysts noted that favorable conditions — broader small refinery exemptions, lower fuel consumption due to high crude prices, reduced export retirements — could ease the burden somewhat. But even the most optimistic combination of these factors would only bring the required monthly pace down to around 850 million gallons, still well above anything the industry had sustained.
The path forward offers three levers: push domestic biodiesel and renewable diesel plants well above their recent 60 percent utilization rates, restore import flows under an uncertain new tax regime, or draw down the RIN bank and carry compliance deficits into future years. How the industry pulls — or fails to pull — these levers will ripple outward into feedstock markets, diesel prices, and the long-term architecture of American renewable fuel policy.
On a March morning in 2026, the EPA released a rule that would reshape the American biomass-based diesel industry for years to come. The mandate was simple on its face: increase the volume of renewable fuel the nation must blend into its diesel supply. But the numbers buried in that rule told a story of unprecedented demand colliding with uncertain supply.
The EPA's final "Set 2" rule, released March 27, established renewable volume obligations for 2026 and 2027 that would require the biomass-based diesel sector to generate between 11 and 12 billion RIN gallons annually—a measure of renewable fuel credits that track actual production and imports. This represented a jump of 55 to 67 percent from 2025's actual generation of 7.1 billion gallons. To put that in perspective: the increase alone between 2025 and 2026 would be nearly four times larger than the entire bank of surplus RINs the industry had accumulated to cushion against shortfalls.
The demand structure driving this requirement came from three sources. The biomass-based diesel obligation itself would be 9.07 billion gallons in 2026 and 9.20 billion in 2027. On top of that, the sector would need to supply 534 million gallons annually for export retirements. And then there was the "D6 pull"—a hidden demand created when conventional ethanol supplies fell short. That pull alone would account for 1.42 billion gallons in 2026 and 1.41 billion in 2027. Together, these three streams created a requirement that had never been asked of the industry before.
The real problem emerged when analysts looked at the monthly pace required to hit these targets. To meet the 2026 obligation, the sector would need to generate an average of 916 million RIN gallons per month. In 2027, that would rise to 991 million gallons monthly. Over the previous three years—2023 through 2025—the industry had averaged 652, 758, and 592 million gallons per month respectively. Only once in that entire period, in December 2024, had monthly generation approached the required pace, hitting 906 million gallons. But that spike was widely understood as a one-time pull-forward of imports triggered by the expiration of a blenders tax credit, not a sign of sustained underlying capacity.
By spring 2026, the early-year numbers were already alarming. January had brought only 436 million RIN gallons, February 478 million, and March 649 million. The cumulative shortfall through the first quarter was roughly 1.18 billion gallons—about 11 percent of the entire annual requirement, gone before April had arrived. The switch from the blenders tax credit to a new 45Z clean fuel production credit had made imported biofuels ineligible for the subsidy, causing import volumes to collapse. To close that gap and still meet the full-year obligation, the remaining nine months of 2026 would need to average nearly 1,090 million RIN gallons monthly—a pace more than 20 percent higher than any single month ever recorded.
The authors of the analysis acknowledged that their projections could prove too pessimistic. If the EPA awarded larger small refinery exemptions than expected, the applicable obligation would shrink. If crude oil prices—which had spiked due to the Iran war—suppressed gasoline and diesel consumption below the EPA's baseline, obligated volumes would fall. If export retirements came in lower than assumed, that would ease pressure too. But even stacking all three of these favorable scenarios together would only reduce the required monthly pace to around 850 million gallons. That would still exceed any sustained average from 2023 through 2025 and would demand generation well above the 592 million gallon monthly average of 2025.
The question facing the industry was stark: How would the market deliver this unprecedented surge? There were three levers to pull. Domestic biodiesel and renewable diesel producers could push capacity utilization far above the 60 percent average rates they had maintained in recent years. Imports could resume a larger role, though the tax credit situation made that uncertain. Or obligated parties could draw down the existing RIN bank and incur compliance deficits to be paid back later. The relative mix of these three responses would determine not just whether the 2026 obligation could be met, but what would happen to feedstock markets, diesel prices, and the entire structure of renewable fuel compliance in the years ahead.
Citas Notables
The biomass-based diesel sector must shift to a level of monthly D4 RIN generation that has, with one transitory exception, never been achieved in any single month over the last three years and must sustain that level for 24 consecutive months.— Todd Hubbs and Scott Irwin, farmdoc daily
La Conversación del Hearth Otra perspectiva de la historia
Why does the EPA set these obligations so far in advance if the industry can't actually hit them?
The percentage standards are locked in now, which means they don't change even if circumstances shift. The EPA projected obligated volumes based on expected fuel consumption, but crude prices spiked due to the Iran war, which reduces demand. They also didn't anticipate how quickly the tax credit switch would kill imports.
So the industry is being asked to do something that's never been done before, and they're already behind in month three?
Exactly. The first quarter shortfall is 1.18 billion gallons. To recover, they'd need to average 1,090 million gallons monthly for the rest of the year. The highest single month on record is 906 million, and that was a one-time surge.
What happens if they can't hit it?
They can draw down the RIN bank—the surplus they've built up—or incur deficits that roll into 2027. But the bank is already projected to drop from 960 million gallons at the end of 2025 to just 200 million by the end of 2026. There's almost no cushion left.
Could domestic producers just ramp up production?
They could try. Capacity utilization has been around 60 percent. But ramping to the levels needed would require sustained operation at rates the industry has rarely achieved. It's not just about flipping a switch.
And imports are off the table now?
Not entirely off the table, but the new 45Z credit doesn't apply to imported biofuels. That removes a major incentive. Imports collapsed when the blenders credit expired, and they haven't recovered.
So what's the most likely outcome?
Probably some combination of all three: higher domestic utilization, some import recovery if prices make it worthwhile, and some deficit carryover into 2027. But the math is brutal. Even under optimistic downside scenarios, the required pace is still unprecedented.