You say tomato waste, I say aviation fuel - EU project gives food for thought

A European Union funded project to produce climate-friendly aviation fuel made from tomato plant waste is underway, with scientists across the continent joining efforts to reduce the carbon footprint of the world's highly polluting air traffic. 

"These are tomato stalks and stems and we used them for our extraction," chemical engineer Sebastian Sandner tells CGTN while extracting fatty compounds from tomato plant residues - which could be the first step towards the world's most sustainable aviation fuel, often referred to as SAF.

While more and more cars are powered by electricity, airplanes still rely on liquid fuels.

"We will not fly with batteries, that's a vision that is probably relevant in 100 years, but not in the next 50 years," project leader Marlene Kienberger explains. 

Aviation is one of the most challenging sectors to decarbonize with sustainable fuels accounting for just 0.1 percent per cent of the market. Experts say far more policy support and investment is needed, if there is to be any significant progress towards wider net zero goals.

Currently, aviation biofuel is made from corn or sugarcane which - according to critics - occupies fertile land that could be better used for food production. This is why Kienberger decided to work with farms to use the organic waste from tomato crops which would otherwise be thrown away.  

"That includes seeds, that includes the shells, any residues that actually are not of value today we want to turn them into sustainable aviation fuels within this project."

Technically a fruit, tomatoes are the second most consumed vegetable in the world after potatoes and the EU is the third largest producer with around 17 megatonnes of tomatoes harvested. 

Their production produces large quantities of residual biomass – plant material such as flowers, leaves and stems, peel and seeds, most of which is currently incinerated as agricultural waste or disposed of at high cost.

Eleven scientific institutions from seven European countries are taking part in the $4 million ToFuel project which in addition to creating sustainable aviation fuel, will produce fertilizer, animal feed and nutritional oil. The technical university in the Austrian city of Graz serves as the main project hub.

The process involves first heating and pressurizing biomass, breaking it down into its cellular components by an abrupt drop in pressure. The subsequent digested biomass sees microorganisms produce lipids that are later processed into aviation fuel. 

The subsequent fractionation, biotechnological and purification processes are being developed by the Laboratório Nacional de Energia e Geologia (LNEG) in Lisbon, TU Graz and the University of Zagreb. 

"The technologies and the process overall that we are kind of developing within this project need to be robust, so that we can also transfer it to other biobased raw materials," Kienberger explains. 

Sourced from tomatoes or other biomass, Kienberger and her international team have four years to create a biofuel and explore the best way to produce it effectively and cost efficiently on an industrial scale. It's giving hope that this red source of fuel… could one day power a green revolution in the skies.