Scientists succeed in transforming food waste into sustainable aviation fuel.

Year after year, millions of tonnes of food waste end up in landfills. There, they generate methane emissions, one of the most powerful greenhouse gases. Now, a group of scientists has demonstrated that the same food waste can be converted into a valuable source of sustainable fuel for aviation.

According to the United Nations Environment Programme, every year, more than 1000 tonnes of food are wasted and in the world, whilst around 783 thousand people are starving.

This study is an important step in the advancement of sustainable fuel sources. In particular, aviation presents a huge challenge in the decarbonisation process. Medium- and long-haul flights require fuels with extremely high energy density to cover long distances, a capability that current batteries cannot yet offer.

But take note: converting food waste into fuel does not mean that wasting food ceases to be a problem. Reducing loss and waste remains the most important strategy. What this study suggests is that, as the world continues to generate waste, a portion of that waste could offer an additional environmental benefit.

From the landfill to an airplane’s fuel tank

The study, published in the journal Nature Sustainability, evaluated not only the technical feasibility of the process but also analysed the economic potential of transforming food waste into sustainable fuel.

El proceso comienza con residuos orgánicos húmedos como materia prima, como sobras de alimentos domésticos, restos de restaurantes o desperdicios de la industria alimentaria. Ellos, en lugar de enviarlos a un vertedero, los someten a un proceso termoquímico conocido como licuefacción hidrotermal (HTL).

The process begins with wet organic waste as the raw material such as household food scraps, restaurant leftovers, or food industry waste. Instead of sending this waste to a landfill, it is subjected to a thermochemical process known as hydrothermal liquefaction (HTL).

This technique uses high-temperature, high-pressure water to rapidly convert organic matter into biocrude—an energy-rich oil that can subsequently be refined into a fuel similar to the kerosene used by commercial aircraft. This type of fuel is known as sustainable aviation fuel (SAF).

Less emissions, less waste

In addition to utilising a waste product, this system could reduce emissions on two fronts simultaneously. On one hand, it would prevent the decomposition of food waste and the release of methane. On the other, it could decrease reliance on the fossil fuels currently used in aviation.

Researchers highlight that the value of this proposal lies in utilising a waste product that currently often ends up in landfills or wastewater treatment plants. Instead of simply becoming waste, these food scraps could be reintroduced into the production cycle as raw material for manufacturing aviation fuel.

Is it possible?

However, demonstrating that something works in the laboratory is merely the first step. The big question is whether it can be produced on a large scale cost-effectively and with a genuine environmental benefit. To this end, they simulated various production scenarios and evaluated the costs of collecting the waste, transporting it, converting it into biocrude, refining it, and distributing the resulting fuel.

An important limitation is that its proposal is designed to be mixed with conventional kerosene, initially in lower proportions or up to 50%, not to completely replace it. This allows emissions to be reduced without the need to modify existing engines or infrastructure.

Their results show that, under certain conditions, this technology could be economically viable and part of a circular economy. However, significant challenges remain before we see this technology operating on a large scale.

The future

For now, the work has been carried out on a small scale. The team has managed to produce several liters of fuel in the laboratory, an amount sufficient to conduct preliminary tests on diesel engines. The next step will be to test it in jet engines, the type that powers most modern commercial aircraft.

The process still entails high costs, but scientists are confident that refining the technology and eventually scaling it up for industrial use will allow those costs to be reduced. In the meantime, science continues to take small steps toward finding solutions to some of the greatest environmental challenges of our time.