Gutter oil, once unwanted waste, is now fueling the skies. In a groundbreaking innovation, companies are turning this discarded cooking oil into sustainable aviation fuel, offering a cleaner, greener alternative to traditional jet fuel. Tao Yuan has the story.

Sichuan's iconic hotpot. Its rich, oily broth part of its unique charm. For years, this leftover oil had nowhere to go – until now. Companies are turning this greasy waste into a surprising solution: clean fuel for the skies, called sustainable aviation fuel, or SAF.

CHEN YU General Manager, Tianzhou New Energy Group "This bottle contains typical hotpot oil, and this one here is the SAF we've processed – clean and transparent as water. Now, we feel that eating hotpot isn't just about enjoying delicious food – it also brings a sense of social responsibility by contributing to carbon reduction in the civil aviation industry."

It's not just hotpot broth. Companies like this one are turning cooking oil waste from restaurants and households, into a substance that will fuel the future of sustainable aviation.

The process is known as HEFA, hydro-processed esters and fatty acids. The oils and fats are first refined to remove impurities. Hydrogen is then added to break down the oils and turn them into liquid fuel. This process can reduce carbon emissions by up to 80 percent over the fuel's lifecycle.

CHEN YU General Manager, Tianzhou New Energy Group "Our raw materials are waste products. During their generation, they actually absorb carbon dioxide. So throughout their overall lifecycle, they can achieve significant carbon reductions. In the future, it's even possible to reach zero-carbon or negative-carbon emissions."

Already, China's SAF program has taken off, quite literally. The current first phase involves 12 flights from four airports. The second phase will start next year, and will see the gradual expansion of the program to involve more airlines and flights.

YAO JUNCHEN Vice Chairman Chinese Society of Aeronautics and Astronautics "Sustainable aviation fuel can be blended with traditional fossil fuels, without requiring any changes to the design of aircraft or engines. This makes it the optimal choice for carbon reduction at present. We advocate for the establishment of an international green aviation organization to lead collective efforts in reducing emissions across the aviation industry."

But like most environmentally friendly products and services, SAF comes with a high price tag, currently estimated to be 3 to 5 times more expansive than traditional petroleum-based jet fuel. And that is largely due to the high production cost and lack of scale.

CHEN YU General Manager, Tianzhou New Energy Group "Currently, we are using SAF in small proportions. Even the European Union will be blending at a two percent ratio starting next year. So the cost increase is actually not going to be dramatic. On another level, companies are constantly working to optimize our processes and reduce production costs. Additionally, from a government perspective, there have been recent changes, such as the cancellation of export tax rebates for used cooking oil. This shift reflects the government's growing support for the SAF industry."

China's existing SAF production capacity is approximately 350,000 metric tons per year, with plans to increase it tenfold in the coming years. Experts believe when it comes to decarbonizing aviation, the ecological payoff makes it worth every drop. Tao Yuan, CGTN, Chengdu.