Waste-based sustainable aviation fuel could generate 62.5 billion liters of jet fuel annually while reducing emissions by 80-90%.

Scientists have found a way to turn everyday trash into jet fuel that produces 80-90% less carbon than traditional aviation fuel. The breakthrough could transform the 2-3% of global greenhouse gas emissions that come from air travel.

Research published recently in Science Direct shows that waste headed for landfills could produce 62.5 billion liters of jet fuel annually. This waste-based sustainable aviation fuel would cover a significant portion of aviation’s fuel needs while keeping organic waste out of dumps where it would decompose and release methane.

The aviation industry faces a major challenge in reducing its carbon footprint. Unlike cars or trucks, which can switch to electric power, airplanes require fuel that packs tremendous energy into a small, lightweight package. This makes the industry one of the hardest to clean up from a climate perspective.

Current alternative fuel options, called sustainable aviation fuels, face their own problems. Growing crops specifically for fuel can displace natural habitats or divert land from food production. This creates new environmental problems while trying to solve old ones.

Enter waste-based sustainable aviation fuel. Michael McElroy, an environmental studies professor at Harvard University, notes that organic waste offers an overlooked opportunity. Cities already collect garbage regularly, and the supply stays consistent throughout the year. These factors make municipal solid waste an attractive starting material for fuel production.

Until now, no one had crunched the numbers on trash-based jet fuel at a global scale, using real data from actual production facilities. An international research team from the United States and China calculated that incorporating waste-based fuel into aviation could reduce the industry’s greenhouse gas emissions by 16%. This would mean the emissions from roughly one out of six flights would be eliminated.

The process isn’t simple. Garbage contains everything from food scraps to paper to yard waste, creating a literal mixed bag of materials. This variety requires more processing steps and more energy to convert trash into usable fuel compared to using a single crop type.

The biggest hurdle happens right at the start. Ming Zhao, an environmental engineering professor at Tsinghua University in Beijing, explains that gasification technology remains a core challenge. This process converts solid waste into a mixture of gases that can then be refined into fuel. Getting it to work reliably and efficiently determines whether the whole system succeeds.

Scientists continue making progress on these technical challenges. A separate team at the University of Illinois focuses specifically on food waste, which makes up the largest portion of what most households discard. They developed a faster method using a process called hydrothermal liquefaction, which converts food scraps into a thick, energy-rich liquid.

The catch with this biocrude oil is its inconsistent chemical makeup. Jet engines require fuel with very specific, uniform properties for safety and performance reasons. The Illinois researchers tested dozens of chemical catalysts to refine the biocrude and found a cobalt-molybdenum combination that works in a single step.

The waste-based sustainable aviation fuel meets current industry standards and can be used directly in airplanes without mixing it with conventional fuel. This marks the first time researchers have achieved this milestone with food waste as the starting material. The same biocrude can also be refined into gasoline and diesel for cars and trucks.

Despite these advances, both research teams acknowledge an important limitation of the waste-based sustainable aviation fuel. Neither food waste nor municipal solid waste alone could completely replace conventional jet fuel. This reality highlights the substantial amount of fuel consumed by the aviation industry and the numerous solutions needed to fully decarbonize air travel.

The waste-based sustainable aviation fuel approach offers several advantages beyond emissions reduction. It addresses two problems at once by diverting organic material from landfills while creating a valuable product. Cities spend a significant amount of money managing waste, so converting garbage into fuel could help offset some of these costs.

The technology also avoids competing with food production and does not require new land to grow fuel crops. The collection infrastructure already exists in most cities worldwide. These factors could make trash-based fuel easier to scale up compared to other alternative fuel options.

However, building the processing facilities and refining operations requires substantial investment. The technology needs to prove itself at a commercial scale, not just in research laboratories. Fuel made from waste must also compete on price with conventional jet fuel, which remains relatively cheap.

Airlines have committed to achieving net-zero carbon emissions by 2050, but they need viable alternatives to make this goal a reality. Sustainable aviation fuels derived from various sources, including waste, are likely to play a crucial role in meeting these targets. Regulatory support and financial incentives may help accelerate the adoption of these cleaner fuel options.

The research demonstrates that waste materials previously considered worthless can become valuable energy resources. As gasification and refining technologies improve, waste-based sustainable aviation fuel may become increasingly practical and affordable. This could help make air travel more compatible with climate goals while improving waste management.