UK Reverses Position on Crop-Based SAF in Significant Policy Shift

The UK government’s recent call for evidence on crop-derived sustainable aviation fuel (SAF) signals a notable shift in policy. For years, official guidance was clear that only waste-based fuels would qualify for support under the SAF mandate. This position helped the UK distance itself from one of biofuels’ most persistent controversies in the food-versus-fuel debate.

That clarity is now fading. With the Department for Transport acknowledging that waste alone may not be sufficient to meet the UK’s 10% SAF target by 2030, crop-based fuels are back on the table.

On the surface, this looks like a pragmatic move to diversify supply and strengthen energy security. In reality, it reflects a more reactive effort to stabilize a domestic ethanol industry that recent trade decisions have left exposed.

From Waste-Only Ambition to Crop Reality

The UK’s ethanol sector has largely been centered around the Vivergo and Ensus plants. However, these plants have been under severe pressure recently.

A policy decision to allow up to 1.4 billion liters per year of tariff-free US ethanol into the UK market dramatically altered the competitive landscape. Less expensive, subsidised US corn ethanol flooded the market and undercut domestic producers that were already operating on thin margins.

The consequences were swift and severe. UK bio-refineries struggled to compete, and Vivergo has already announced its closure.

Against this backdrop, the government’s openness to crop-derived SAF looks less like a strategic pivot and more like a rescue attempt.

By allowing crops into the SAF mandate, policymakers are effectively creating a new outlet for domestic ethanol via the alcohol-to-jet (ATJ) pathway. The move could offer UK producers a lifeline beyond gasoline blending, a market now dominated by imports.

A Mandate Growing More Complex by the Month

The mechanics of the shift are understandable. If domestic ethanol can be upgraded into jet fuel, it creates a new demand pull from aviation. This offers a highly desirable pathway as aviation remains a sector with far greater long-term growth potential than road fuels.

However, the policy architecture underpinning this transition is becoming increasingly convoluted. The call for evidence suggests a cap on crop-based SAF to limit food-versus-fuel risks.

While caps are not inherently problematic, the UK SAF mandate is already heavily fragmented:

• A cap on HEFA (Hydroprocessed Esters and Fatty Acids), currently the only SAF pathway supplied into the UK
• A proposed cap on crop-based SAF
• A sub-mandate for PtL (Power-to-Liquid) Fuels

For a mandate that is less than a year old, this level of complexity risks creating uncertainty for investors and project developers alike.

The Carbon Debate Returns

The government has continued to stress that any crop-based SAF must still meet greenhouse gas (GHG) reduction thresholds. In theory, converting UK feed wheat into ethanol and then into SAF via ATJ could lower aviation’s overall carbon intensity.

In practice, this is a familiar battleground.

In the US, crop-based ethanol has long faced criticism over whether it delivers meaningful carbon savings compared to fossil fuels. That same debate now looks set to re-emerge in the UK, as stakeholders scrutinize the environmental credentials of crop-derived SAF.

Lower Costs, Higher Adoption

What is far harder to dispute is the cost impact of introducing crop-based SAF.

Alcohol-to-jet is widely seen as one of the most promising pathways for lower-cost SAF production. But its economics are heavily influenced by feedstock prices. Restricting ATJ to waste-based ethanol has undermined its competitiveness because waste ethanol is both higher-value and limited in supply.

Opening the pathway to crop-based ethanol changes that equation dramatically.

ATJ SAF prices can vary widely depending on feedstock and geography. Subsidized US corn ethanol sits at the lower end of the cost curve, enabling SAF prices below $1,500 per ton. By contrast, waste-based, cellulosic ethanol can push SAF prices above $2,500 per ton.

Introducing crop-based ethanol into the mix gives ATJ a clear role as a cost-competitive option for meeting SAF mandates. This could significantly reduce the overall cost burden on airlines.

A Policy Irony Hard to Ignore

There is an undeniable irony at the heart of the UK’s evolving SAF policy. After years spent trying to move away from crop-based biofuels, the government now finds itself embracing them to protect industrial and agricultural jobs in the north of England.

While the official narrative frames this as a necessary broadening of the fuel mix, the underlying driver is clear. The UK must stabilize a domestic industry that previous policy decisions helped to destabilize.

The waste-only vision may have been politically convenient. But the realities of supply, cost, and industrial resilience have forced a rethink. Crop-based SAF is back, and it’s not because it was the preferred option. Instead, it’s because it may now be the only viable option for the UK moving forward.

Want a Deeper Look at What’s Driving SAF & Biofuels Markets?

If you’re trying to make sense of where sustainable aviation fuel (SAF), biofuels, and low-carbon feedstocks are headed, we’ve got you covered.

Our Biofuels Market Outlook 2026 webinar, led by ResourceWise VP of Low-Carbon Fuels Mat Stone, offers a data-driven, forward-looking view of the forces shaping the industry next year and beyond. You’ll gain actionable insights into:

• How policy and regulatory shifts (especially RED III) are influencing markets

• Evolving feedstock supply dynamics, including crop vs. Annex IX streams

• SAF market fundamentals and what demand growth means for pricing and strategy

• Emerging trading trends and where opportunities are forming in 2026

Watch the Biofuels Market Outlook 2026 webinar on demand and stay ahead of what’s next.