Green methanol – A raw material for sustainable aviation fuels

Air travel causes around 3.1 percent of global CO₂ emissions and will continue to rise in the coming years. Researchers at the German Aerospace Center (DLR) even predict that air travel will increase by 3.5 % annually by 2040. So it's high time to develop alternative fuels, so-called Sustainable Aviation Fuels (SAF). Green methanol could serve as a feedstock for these sustainable fuels. We asked our experts at thyssenkrupp Uhde: What is green methanol? How is green methanol produced? And: Does it have the potential to become a raw material for a sustainable alternative to kerosene?

Our modern society is dependent on air travel. The thousands of kilometers that our goods and we travel in the air generate thousands of tons of CO₂ emissions. The previously mentioned Sustainable Aviation Fuels could have a major impact on our environment. "The term covers sustainably produced fuels that are not based on fossil raw materials," explains Dr. Thomas Streich, Global Head of Green Technologies & Decarbonization Portfolio in the Operating Unit Petrochemicals and Polymers at thyssenkrupp Uhde. "They can either be derived from biomass or be synthetic fuels based, for example, on green methanol produced from renewable energies and CO₂."

With thyssenkrupp nucera and thyssenkrupp Uhde, thyssenkrupp already offers the production of green hydrogen and the production of green methanol. Streich and his colleagues are currently developing process steps to convert green methanol into Sustainable Aviation Fuel as part of a project funded by the German government to the tune of €3.1 million.

Green methanol: A feedstock for a sustainable alternative for kerosene?

"To understand the role of green methanol in more sustainable aviation, it is important to know that methanol cannot be a direct substitute for kerosene due to its low energy density," Streich explains. Nevertheless, green methanol could play a key role in CO₂-neutral aviation in the future and is suitable as a feedstock for Sustainable Aviation Fuels, says the expert. This is because the aviation industry is required by law to use an ever-increasing proportion of Sustainable Aviation Fuels.

Several process routes can be considered for this. "All current Sustainable Aviation Fuels have in common that they are used in a blend with conventional jet fuel, with the blending rate usually limited to a maximum of 50%, depending on the production route," Streich explains. "Our goal is to design the conversion steps from green methanol to synthetic kerosene to produce a sustainable kerosene substitute that can be used 100% directly in the propulsion units." However, it's not just the use of a sustainable feedstock, such as green MeOH in our case, that's required, Streich says: "The process steps in the downstream conversion must also be effective and low in emissions."

What is green methanol and how is green methanol produced?

But what is green methanol and how is green methanol produced? Methanol is one of the most widely produced organic chemicals today, at around 110 million tons annually. Conventional production uses fossil raw materials such as natural gas or coal. "Green," on the other hand, is the popular term for sustainably produced energy and products. Green methanol is produced either from biogenic feedstocks (e.g. biomass gasification) or from carbon dioxide (CO₂) extracted from the air together with green hydrogen (from water electrolysis with sustainable electrical energy).

With a few more process steps, this green methanol can finally be processed into synthetic kerosene and thus into a CO2-neutral alternative for traditional jet fuel. "Although CO₂ is also produced during the combustion of synthetic kerosene, the crucial difference is that only as much CO₂ is released into the atmosphere as was previously removed from it for the production of green methanol, i.e. through artificial CO₂ capture, for example," says Streich. Therefore, the combustion of Sustainable Aviation Fuels is CO₂-neutral on balance.

The methanol route also offers some advantages over other Sustainable Aviation Fuels production processes, Streich said. However, it does not yet have regulatory certification for release as an aviation fuel (by the ASTM organization), which is currently being initiated. Depending on the progress of the certification and development, however, the expert expects that aviation fuels based on green methanol could be used commercially starting around 2026.

Sustainable Aviation Fuels: The Contribution of thyssenkrupp Uhde

In the publicly funded M2SAF project, which was successfully launched in August 2022 with renowned partners such as BASF Process Catalysts, OMV Germany, DLR and ASG, thyssenkrupp Uhde is contributing its experience and technology expertise from over 100 years of plant engineering. The focus is on the development of technology which optimizes the process steps in terms of reaction control and efficiency and the integration of the individual processes into an economical and sustainable overall process. Moreover, thyssenkrupp Uhde will also design the necessary pilot plant and determine the total investment costs for a commercial plant.

Can politics and the energy industry also structurally support the development of Sustainable Aviation Fuels? "All current green processes, fuels, chemicals, etc. based on biogenic feedstocks or green hydrogen will compete for these resources or green power in the future," explains Streich. According to his assessment, the allocation of these basic materials to the manifold products will in the future largely depend on legal framework conditions and corresponding restrictions, e.g. the level of CO₂ emission pricing.

"Provided sufficient green hydrogen and suitable CO₂ are available, thyssenkrupp could then, from a purely technical point of view, build plant capacities that, in combination with the capacities of other Sustainable Aviation Fuels, could meet the necessary quota requirements," says Streich.

Sustainable Aviation Fuels made from green methanol arean important step towards more sustainable air transport and logistics. Find out more about thyssenkrupp's green technologies and innovations in our Sustainability Stories.