Flying’s Environmental Impact Is Undeniable. Is Sustainable Aviation Fuel the Answer?

Unlike kerosene-based jet fuel, SAF is produced from renewable or recycled bio-organic sources and can lower total greenhouse gas emissions over time. It can be produced from biomass like corn, used cooking oil, and agricultural residues, as well as from municipal waste or synthetic fuels made by combining captured CO₂ with green hydrogen (‘power-to-liquid’). Importantly, SAF is a ‘drop-in’ fuel that can be blended with conventional jet fuel and used in today’s aircraft without engine modifications. The fuel produces nearly the same amount of CO₂ as traditional jet fuel when burned. But because SAF is made from renewable or recycled carbon sources, net lifecycle emissions can be up to 80 percent lower, according to the International Air Transport Association (IATA). Ultimately, the IATA estimates SAF could make up 65 percent of the emissions reduction need for aviation to reach net-zero CO₂ emissions by 2050. It’s an important piece of the pie in addition to improving technology like carbon capture.

The need for SAF is rising. Commercial aviation accounts for about 2.5 percent of total global greenhouse gas emissions. As other sectors of the economy become more sustainable and the amount of flights around the world increases, the share of total emissions from flying will only grow – unless airlines can find effective ways to lower their environmental impact. In addition to carbon capture, which involves pulling carbon from the air and storing it underground, the adoption of SAF is increasingly viewed as a viable means for the aviation sector to reduce its emissions.

Still, a spokesperson for Neste, a Finnish energy company founded in 1948, told me there’s still a long way to go. Total SAF usage currently accounts for less than .2 percent of total global jet fuel consumption.

Neste, originally focused on securing Finland’s oil supply, has transformed over the decades into a SAF leader focused on renewable and circular energy solutions. Neste’s Singapore refinery is the world’s largest SAF facility, capable of producing 1 million tons annually. Neste isn’t alone. Boston’s World Energy, founded in 1998, became the world’s first commercial-scale producer of SAF in 2016, while Reno-based XCF Global recently became the first publicly traded SAF company in the United States.

The industry is gaining traction, though critics remain skeptical of SAF’s scalability and environmental value. Its future is far from guaranteed, and SAF alone is unlikely to erase aviation’s heavy carbon footprint. Still, momentum is building. Commercial aviation may be moving toward a cleaner future. What role SAF will play remains unclear.

How SAF works

SAF is straightforward in concept but complex to produce. The most common production method is known as HEFA (Hydroprocessed Esters and Fatty Acids), which uses renewable oils and fats such as used cooking oil, animal fats, and some non-food vegetable oils. These are treated with hydrogen at high temperature and pressure to remove oxygen and impurities, producing paraffinic hydrocarbons that closely resemble conventional jet fuel and can be blended directly (hence the term “drop-in” fuel).

Sustainability efforts are highly marketable these days. While companies that reduce their environmental impact deserve credit, consumers are wary of greenwashing. Delta Air Lines was the first US carrier to offer offsets when travelers book flights in 2007, and doing so is now an industry standard. It’s easy to see this as shifting the sustainability burden to consumers rather than the companies. SAF instead allows companies to take a bigger responsibility in reducing emissions.

Corporate entities can buy SAF certificates (SAFc) to document emissions cuts as their people and goods are flown around the world, known as Scope 3 emissions. SAFc uses a system called ‘insetting,’ which separates the verified emissions savings from the fuel itself. Airlines can then apply those savings to their overall carbon footprint from flights. This sounds similar to how carbon offset credits, which have been shown to be ineffective without strict monitoring, are applied. But the SAFc system is considered more reliable because it’s tracked through a ‘Book and Claim’ ledger. This helps prevent double counting of emissions reductions, ensure integrity, and allows SAF to be used where most efficient, all while still letting companies claim the associated emissions cuts in their supply chains.

This could prove to be the key difference in helping both the public and airlines get on board with developing and implementing more SAF use.

“Delivering the emissions reduction value of SAF with SAFc insets is increasingly recognized as the best tool to scale investment in the SAF industry,” Karen Boyd, director of product sustainability at World Energy, says.

Where does current policy on SAF stand?

The International Civil Aviation Organization (ICAO) has set a net-zero target for 2050. It introduced a Global Framework calling for a 5 percent emissions cut by 2030 through SAF and lower-carbon fuels. The European Union’s ReFuelEU regulation is the most ambitious program in the world, requiring airlines to blend their jet fuel with 2 percent SAF by 2025, 6 percent by 2030, and 70 percent by 2050, with dedicated targets for synthetic e-fuels. The UK has set a similar path with a 9.5% SAF target by 2030, while Ireland recently launched its first national SAF roadmap. In North America, the US Inflation Reduction Act offers SAF tax credits and $300 million for research and infrastructure, while Canada supports production through mandates, incentives, and public–private partnerships. Time will tell whether any of these benefits survive the current administration’s environmental rollbacks.

India, Brazil, and a handful of other countries also have SAF mandates in place. China, South Korea, Turkey, and the UAE are developing frameworks. By 2030, government mandates are expected to cover about 75 percent of global jet fuel use, requiring airlines to use roughly 2 billion gallons of SAF each year. That’s far more than the 1 percent of global jet fuel that SAF accounts for today, with production constrained by feedstock scarcity, high costs, and delayed projects.

The gap between policy goals and current supply means scaling up investment and infrastructure is essential. Still, Neste says global SAF production is sufficient to meet existing mandates in the EU and UK. That’s because these mandates are currently quite low – and because the ongoing expansion of Neste’s Rotterdam refinery will bring the company’s total SAF production capability to 2.2 million tons annually in 2027. XCF and other producers are scaling in the same manner.

Progress and making the costs make sense

In June 2025, XCF Global, a synthetic aviation fuel producer, took the vision for decarbonized air travel directly to Wall Street when it went public via a merger with Focus Impact BH3 Acquisition Company under the ticker SAFX. The company promotes “feedstock-agnostic technology” that isn’t reliant on corn or monocrop agriculture. At the company’s facility in Reno, Nevada, it produces SAF in the largest industrial park in the country.

“SAF in our opinion is going to be one of the most predominant ways to decarbonize the aviation industry,” Mihir Dange, CEO of XCF, told Matador. “I think that’s the purpose of why we intended on going public is we wanted to add to the legitimacy. To bring visibility to what’s happening in our business but as well as what’s happening in the market.”

Technological improvements and availability are one step to a more sustainable industry, but won’t have the intended impact if it’s still too expensive to implement. XCF Global’s business plan is key to growing the sector as a whole. The company reduces costs by having its facility in a location near a source for various types of feedstocks like tallow, cooking oil, the waste byproduct distillers corn oil, and soybean oil.

Dange acknowledges the challenges but feels like his business, and SAF more broadly, is well-positioned for growth. Meeting the 2050 goal of a 70 percent decrease in carbon intensity will require roughly 100 times today’s infrastructure, he said, adding “we’re just not building infrastructure that fast.”

“I don’t consider [other SAF companies] competitors” in the bigger picture of a more sustainable future, Dange said. “We need as much staff infrastructure as we can to come online to help meet the demands of the future, to help reduce the carbon intensity around aviation.”

He argues that success depends on industry and regulators working together to create consistent global standards. Clear reporting and verification will not only move the sector forward but also build public trust — a view echoed by World Energy and Neste.

“We take our Life Cycle Assessment (LCA) calculations very seriously, conducting rigorous evaluations that account for full cradle-to-grave emissions and vetting them through independent third-party audits on an annual basis to ensure transparency and accuracy,” says Boyd, of World Energy. “This approach aligns with industry standards. Where properly certified SAF achieves at least a 50 percent lifecycle emissions reduction compared to conventional jet fuel, our SAF can achieve up to 85 percent in optimal cases using waste-based or advanced feedstocks.”

The case against sustainable aviation fuel

Sustainable aviation fuel isn’t without critics who point out that SAF comes with its own inherent climate risks. For one, corn requires an immense amount of land and water to grow.

Chuck Collins, director at the Institute for Policy Studies, is a vocal critic of SAF. He coauthored the 2024 report “Greenwashing the Skies” that argued SAF is largely a marketing ploy and not a scalable solution for aviation emissions. He and his coauthors point out that current SAF production is nowhere near what would be required to meet US climate goals, a valid stance.

The report notes that scaling up would demand massive subsidies and land-use changes, and that the aviation industry has a poor track record of meeting its own SAF targets. Collins also warns that including fuels like corn-based ethanol could worsen climate impacts due to land clearance and soil loss.

To produce enough corn-based ethanol to replace just 10 percent of current US jet fuel demand, corn yields and production methods would need major improvements. Replacing 100 percent of jet fuel with corn-based ethanol would be far more damaging and would require vast new cropland that reduces forests and strains water supplies.

Other vocal critics include airline executives themselves. AirAsia co-founder Tony Fernandes has called SAF “stupid”, and, like Collins and the IPS, questions its scalability given feedstock limitations and cost. Breeze Airways CEO David Neeleman agrees, telling Skift that SAF is economically and environmentally inadequate.

Collins and other SAF opponents call for rejecting ethanol-based SAF due to the harmful lifecycle impacts, and instead push for independent, science-driven research rather than what Collins has described as industry-influenced standards. His warning that turning farmland into fuel crops would be disastrous has merit, though it may overlook other viable SAF pathways.

Even industry players recognize these concerns – and are working to address them.

“Critics’ worries about scalability and environmental trade-offs, such as those from biofuel competition with food crops, are being addressed through evolving frameworks like ICAO’s sustainability criteria,” Boyd says. “Ultimately, dismissing SAF entirely overlooks its role in aviation’s net-zero pathway, but ongoing scrutiny drives improvements in production and certification to maximize real-world decarbonization.”

Embracing today’s solutions while building tomorrow’s

Waiting for researchers to develop a silver bullet solution is an increasingly less viable option as the effects of climate change speed up. Still, for SAF to be viable, more production methods need to be embraced to turn waste into energy.

One place to find inspiration is Denmark. Copenhagen’s CopenHill (Amager Bakke) plant burns the city’s non-recyclable waste in a high-efficiency incinerator, generating both electricity and hot water for tens of thousands of homes. If similar waste-to-energy plants were adapted to produce jet fuel using advanced filtration and catalytic systems to capture pollutants, the result could be cleaner than today’s kerosene while also diverting waste from landfills and cutting methane emissions. CopenHill is especially notable for its design: the plant doubles as a recreation space, with a ski slope, climbing wall, and hiking trails built into its sloping roof, helping secure public support.

Technology isn’t the only challenge to increasing production, however. Regulatory uncertainty remains one of the industry’s biggest roadblocks.

“The primary regulatory obstacles to scaling SAF production involve inconsistent international policies and varying sustainability criteria across jurisdictions, which can hinder compliance and deter investment in certain pathways or regions,” Boyd says.

She adds that regulatory uncertainty in both the US and EU, such as delays in tax credits and blending mandates, continues to slow progress. The Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) provides a framework to standardize international aviation emissions reductions, but its impact is limited by patchy participation and uneven carbon pricing.

The future for SAF – and what travelers can do now

The core takeaway is clear: For SAF to both scale and notably reduce the emissions of the aviation sector, production must be done responsibly with consistent global regulation and enactment.

For travelers, small steps matter too. Airlines including Alaska, JetBlue, and Turkish now allow flyers to “purchase” SAF credits at checkout, effectively only contributing a couple bucks to the cause but importantly voicing their support.

“I would emphasize that while some concerns are valid and highlight the need for careful pathway and feedstock selection,” Boyd says, “the evidence shows SAF can deliver substantial net GHG reductions when produced responsibly.”

For travelers from the US, a successful way forward involves educating both the public and lawmakers on the benefits, and supporting organizations, politicians, and individuals advocating for responsible development. Each step to replace fossil fuels with a more sustainable alternative is a step in the right direction. When SAF-powered long-hauls like Virgin’s Flight100 become the norm is still years or decades away – but in the broad stroke of human progress, this time is a blink of the eye.