Everyday trash — including food waste, discarded metals, rubber, and other municipal solid waste — can be converted into sustainable aviation fuel (SAF), according to a new study published last month in Nature Sustainability. The research was conducted by scientists from the Harvard-China Project on Energy, Economy, and Environment and Tsinghua University in Beijing, reports The Harvard Crimson.
The study found that municipal waste can be transformed into a liquid feedstock capable of significantly lowering greenhouse gas emissions compared to conventional jet fuel. Researchers also concluded that waste-based fuels could be more dependable and cost-effective than many other sustainable fuel options.
The team began the study with a clear objective: to find ways to cut carbon emissions in aviation, a sector responsible for about 2.5% of global emissions. Jingran Zhang, a postdoctoral fellow with the Harvard-China Project and the study’s lead author, said the aviation industry has limited possibilities for electrification, making sustainable jet fuels an essential alternative.
“We’re trying to find a feedstock that is low-cost, consistently available, and produces fewer emissions,” Zhang said.
Municipal waste was chosen partly due to growing concerns among policymakers about managing expanding trash volumes, especially waste that does not break down easily. “We are trying to align the goal of zero-waste cities with carbon-neutral aviation,” Zhang explained. “This approach has the potential to meet both goals at once.”
While previous research has shown that jet fuel can be produced from crops like vegetable oil, such sources suffer from unclear emissions benefits and scaling challenges. In comparison, municipal waste is abundant year-round and not subject to seasonal fluctuations.
The project began two years ago when researchers at Tsinghua University began converting waste into a light gas through gasification, a process that can produce biofuels. But making the gas clean enough for fuel use proved difficult because of its high moisture levels and heavy filtration requirements. “Gasification is the main bottleneck in the process,” Zhang said.
Zhang described the collaboration between Harvard and Tsinghua teams as “a perfect match,” with one group focusing on gasification technology and the other on aviation-sector solutions.
The team now plans to expand the research to other sectors that depend on fuels, including exploring low-carbon alternatives like methanol. Zhang emphasized that waste-derived jet fuel is only one pathway toward sustainable aviation, but each step adds to global understanding of how to decarbonize the industry.
“Thinking in this direction helps us understand what we can do to support a carbon-neutral future,” she said.
