Airlines promised a rapid shift to sustainable aviation fuel to tame climate chaos. Our review of industry data, peer analysis, and company filings finds a stark gap between pledges and production. A highly publicized early success, the World Energy refinery in Paramount, California, has closed, expansion partners have exited, and many marquee projects are delayed or abandoned. Even under optimistic scenarios, current plans cannot deliver the volumes required for net zero. Better solutions will require transparency, demand reduction, mode shift on short routes, and risk sharing that goes far beyond press releases.
In 2019, United Airlines touted a landmark supply agreement with World Energy, which produced sustainable aviation fuel at a refinery in Paramount, just south of downtown Los Angeles. The site used a process known as HEFA to refine used cooking oil and animal fats into a drop‑in jet fuel blend. For a time, Paramount was the proof point that airlines could decarbonize without changing how they fly. By April 2025, the plant had gone quiet and staff were laid off, and by February its expansion partner Air Products had terminated its participation in a planned multibillion dollar upgrade, citing challenging commercial conditions. Independent reporting and industry trade coverage documented the shutdown and partner withdrawal, while earlier company materials had described an ambitious capacity expansion now on ice. See coverage and documents from Biomass Magazine, SAF Investor, and EIA.
The International Air Transport Association projects that sustainable aviation fuel will supply only about 0.7 percent of global jet fuel in 2025, up from 0.3 percent in 2024. Hitting the industry’s net zero target by 2050 would require about 118 billion gallons per year, a more than 300‑fold scale‑up from current output. These figures come from IATA’s latest fact sheet and AGM briefings. Source.
A detailed newsroom database compiled by reporters found airlines had announced 165 SAF projects over the past twelve years, yet only 36 had produced any fuel as of mid‑2025. Even if every pending project reached maximum potential, they would add only about 12 billion gallons, roughly one tenth of what would be needed for net zero. Analysis.
Nearly every commercial‑scale SAF project to date relies on HEFA, which converts fats, waste oils, and greases into jet fuel through hydrotreating and subsequent refining steps. HEFA is proven at small scale, but it faces three hard constraints:
These are not theoretical concerns. The Paramount expansion faltered precisely where feedstock availability, cost inflation, and uncertain offtake collided. See project background in World Energy’s 2023 report and subsequent coverage of Air Products’ exit from the deal here and here.
The most frequently cited non‑HEFA pathway is gasification plus Fischer–Tropsch synthesis using municipal solid waste, wood residues, or flare gas. In principle, this taps more abundant feedstocks. In practice, it is complex and costly. Velocys, a prominent developer, has received UK government grants for its Altalto project and maintains a long‑standing partnership with IAG, yet it has not reached commercial sales after more than a decade of development. The Immingham site remains in development, while the company seeks clarity on policy and financing. See updates from Velocys and earlier notices here. These challenges mirror wider findings that technology readiness, integration risk, and high operating costs remain unresolved at scale. A broader context on aviation decarbonization uncertainties is discussed in this policy overview.
SAF typically costs three to five times more than conventional jet fuel. Producers argue they cannot finance plants without long‑term, take‑or‑pay contracts and public support. Airlines counter that refiners are not delivering enough volume and that costs must fall. The stalemate is visible in high profile projects that slip years beyond initial timelines, then pivot to renewable diesel for trucks and ships where demand is steadier. The SGP BioEnergy project in Panama, once promoted as the world’s largest SAF facility using industrial hemp and used cooking oil, has delayed production to 2027 and may prioritize renewable diesel. See reporting here and aggregation here.
The European Union has adopted binding SAF blending requirements for fuel supplied at EU airports that begin at 2 percent in 2025, rise to 6 percent in 2030, and reach 70 percent in 2050. The regulation also creates a rising sub‑mandate for synthetic aviation fuels. Source and Commission page.
In the United States, policy support has relied on tax credits and grant programs that are sensitive to political cycles. With shifting federal priorities, projects face real policy risk at the moment financing decisions are needed. The result is a slower build‑out compared with Europe and a larger gap between press announcements and funded projects.
Aviation currently contributes on the order of 2 to 3 percent of global carbon dioxide emissions. If other sectors decarbonize faster while air travel demand keeps growing, aviation’s share rises. Transport and Environment estimates that, even with efficiency improvements, fuel burn in 2050 for flights departing EU airports could be 59 percent higher than in 2019 if manufacturer traffic projections hold. Summary and detailed report PDF.
SAF can reduce emissions relative to fossil jet fuel, but outcomes depend on the source of feedstocks and process energy. HEFA made with fossil hydrogen delivers smaller benefits than versions that rely on additional clean hydrogen. If increased demand drives indirect land use change or displaces food production, net climate performance can deteriorate. Gasification and Fischer–Tropsch can avoid some land risks but raise others, including high energy use for feedstock preparation and gas cleanup, and the need for clean power and hydrogen at scale.
Without strict sustainability guardrails and clear lifecycle methodologies, SAF can drift into the category of false solutions, offering a perception of progress while locking in new investments that depend on scarce feedstocks or fossil inputs.
The industry frequently points to a coming wave of projects, yet there is no public, standardized, and independently verified database that links each announcement to a physical site, financial close date, technology pathway, feedstock contract, expected emissions intensity, and binding offtake. Newsrooms have begun to fill the gap with open databases and on‑the‑ground reporting, but the burden should not fall to journalists. A credible pathway requires routine disclosure of plant‑level data and a willingness to publish misses beside milestones. See one such newsroom database and analysis here.
SAF has a role, particularly for long‑haul flights where alternatives are limited. Yet the largest near‑term emissions reductions come from measures that reduce total fuel burn. These are the better solutions that are available today:
If policymakers and airlines want SAF to contribute meaningfully without repeating past mistakes, several design choices matter:
Paramount in California showed that an early HEFA site could run, but also how fast the economics can turn when expansion costs rise and policy or offtake wavers. Air Products’ exit preceded the suspension of operations. Read more.
In Panama, SGP BioEnergy drew headlines with plans for the largest SAF facility and a novel feedstock slate. As airline commitments softened, timelines stretched to at least 2027 and the company publicly contemplated shifting output to renewable diesel for road and marine uses. Coverage.
At Immingham in the UK, Velocys continues engineering work with public grants and industry partners. The project symbolizes both the promise of a broader feedstock base and the cost and integration hurdles that must be solved to move beyond pilots. Project update.
Airlines can either meet climate goals or maintain unconstrained growth using minimal SAF. The physics and the math do not allow both. A strategy that leans on scarce HEFA feedstocks, speculative timelines for complex gasification plants, and a patchwork of voluntary offtake letters invites disappointment. It also risks diverting attention from measures that cut emissions now.
Sustainable aviation fuel is not a scam, but the current narrative often turns it into a shield that deflects scrutiny and delays systemic change. As long as SAF is marketed as the main plan while volumes remain tiny, it functions as a false solution. Great solutions will combine verified volumes of the best SAF pathways with policies that right‑size demand, accelerate rail and digital substitution for short and medium trips, and improve operations that cut fuel burn on every flight.
Airlines, manufacturers, fuel producers, and governments can still chart a credible path. It will require honest math, public data, and a willingness to accept that some flights will have to change or disappear. In a warming world, progress is measured in actual tons of carbon not emitted, not in the thickness of a press kit.