A new study has found that municipal solid waste can be converted into sustainable jet fuel, cutting aviation emissions by up to 90 % and offering a scalable, cost-effective alternative to traditional fuels.
Image Credit: Ivan Marc/Shutterstock.com
Aviation currently accounts for about 2.5 % of global carbon emissions, and with air travel demand expected to double by 2040, reducing those emissions is becoming increasingly urgent.
One of the more promising solutions is sustainable aviation fuel (SAF), a low-carbon alternative made from sources like used cooking oil and certain crops. But despite its potential, SAF still represents less than 1 % of global jet fuel use, largely due to high production costs and limited supply.
Now, new research published in Nature Sustainability highlights a fresh opportunity to expand SAF production: turning municipal solid waste into jet fuel. The study shows this widely available, low-emission resource could help close the supply gap in a practical and affordable way.
Led by researchers from Tsinghua University and the Harvard-China Project on Energy, Economy, and Environment, the study evaluated how municipal solid waste (MSW) can be converted into jet fuel using industrial-scale gasification and Fischer-Tropsch synthesis.
A life cycle analysis found that MSW-based jet fuel could reduce greenhouse gas emissions by 80–90 % compared to conventional fossil-based jet fuel.
The main technical challenge, researchers noted, lies in scaling up gasification systems for widespread use.
Unlike road transport, which is quickly shifting toward electrification, there’s no silver-bullet solution for achieving carbon-neutral aviation. Turning everyday trash into jet fuel could be an innovative but major near-term step toward cleaner aviation. By converting municipal waste into low-carbon jet fuel that already works in today’s engines, we can start cutting emissions immediately, without waiting for future technology.
Jingran Zhang, Study First Author and Postdoctoral Fellow, Harvard-China Project, Harvard John A. Paulson School of Engineering and Applied Sciences
Zhang is supported by the Salata Institute for Climate and Sustainability at Harvard.
Rethinking Municipal Waste
Municipal solid waste covers just about everything we throw away (food scraps, paper, plastics, and even metals). Most of it still ends up in landfills or gets incinerated, which either takes up space or adds to air pollution.
With cities generating more waste and running out of landfill room, turning that trash into fuel could offer a smart two-for-one: cutting emissions while easing the pressure on waste systems.
What sets this study apart is that it doesn’t rely on theory. Instead, it uses real-world data from existing Fischer-Tropsch gasification technology.
The researchers dug into where emissions come from in the process, how much carbon is saved, and where there’s room to do better.
Right now, only about a third of the carbon in the waste ends up in the fuel, mostly because the gas makeup isn’t quite ideal. But there are ways to boost that efficiency, like capturing the leftover carbon dioxide or adding green hydrogen made with renewable power during processing.
Global Implications
Countries around the world are stepping up their efforts to make aviation cleaner, with a growing focus on sustainable fuels. In the US, the federal government has set an ambitious target to produce up to 35 billion gallons of sustainable aviation fuel (SAF) per year by 2050, backed by substantial financial incentives.
Meanwhile, the European Union is rolling out new regulations requiring all departing flights to gradually ramp up their SAF use - from 2 % in 2025 to 70 % by mid-century.
Globally, the International Civil Aviation Organization’s CORSIA program is also pushing airlines to offset emissions growth, either by purchasing approved carbon offsets or by using low-emission fuels like SAF.
The Harvard study examined several potential scenarios for converting municipal solid waste into jet fuel.
In the most realistic case, global waste streams could produce about 50 million tons (62 billion liters) of SAF annually, which is actually enough to cut aviation-related greenhouse gas emissions by roughly 16 %.
If the waste conversion process itself is not efficient, the climate benefits drop off.
But if green hydrogen, which is made using renewable energy, is added during production, fuel output could rise to 80 million tons a year. That’s enough to cover up to 28 % of global jet fuel demand and slash emissions by as much as 270 million tons of CO2 annually.
In Europe, even conservative estimates suggest that MSW-based SAF could easily surpass upcoming blending targets while staying within sustainability guidelines.
From a cost perspective, the study also found that this approach could save airlines money, especially under carbon pricing systems like CORSIA, once government incentives and subsidies are factored in.
In the end, sustainable aviation fuel still accounts for less than 1 % of global jet fuel use - largely because it’s expensive to produce. That gap highlights just how crucial strong policy support and financial incentives are if we want to scale up supply and make low-emission flying a viable reality.
This study presents a blueprint for converting urban waste into sustainable aviation fuel, offering future environmental and economic benefits. Moving forward, broad collaboration among governments, fuel producers, airlines, and aircraft manufacturers will be essential to increase production, lower costs, and accelerate aviation’s path to net-zero emissions.
Michael B. McElroy, Gilbert Butler Professor, Environmental Studies, Harvard John A. Paulson School of Engineering and Applied Sciences
Journal Reference:
Zhang, J., et al. (2025) Powering air travel with jet fuel derived from municipal solid waste. Nature Sustainability. DOI:10.1038/s41893-025-01644-3. https://www.nature.com/articles/s41893-025-01644-3#.