Green energy
European Union regulations designed to accelerate the shift toward sustainable aviation fuel (SAF) may unintentionally increase energy consumption, raise production costs and place additional pressure on limited biomass resources, according to new research from Chalmers University of Technology.
The study raises fresh concerns about whether current EU policies are fully aligned with broader environmental objectives, including carbon reduction, resource efficiency and long-term sustainability.
As Europe pushes to decarbonise aviation, researchers warn that some of the regulations intended to support cleaner fuels may instead encourage production pathways that consume more electricity and generate greater environmental inefficiencies.
Under the EU’s aviation decarbonisation strategy, fuel suppliers must now blend sustainable aviation fuel into jet fuel sold at European airports. The mandate begins at 2% and will rise steadily to 70% by 2050.
Half of that future SAF supply must come from Renewable Fuels of Non-Biological Origin (RFNBOs), commonly known as electrofuels. These fuels are produced using renewable hydrogen and captured carbon dioxide and are viewed as a key component of Europe’s climate transition strategy.
However, researchers at Chalmers say the current regulatory framework may be unintentionally steering investment toward less sustainable fuel production systems.
Henrik Thunman
“Instead of driving innovation towards the most efficient solutions, we risk locking ourselves into less resource-efficient production methods,” said Henrik Thunman, Professor of Energy Technology at Chalmers University and co-author of the study.
The research examined three different methods for producing synthetic methanol, an important building block for sustainable aviation fuel.
Two of the production routes rely on biomass combustion, where carbon dioxide is captured from flue gases and then combined with renewable hydrogen. The third pathway uses biomass gasification, a process that converts biomass directly into synthesis gas containing both hydrogen and carbon.
Although all three methods can produce the same end fuel, the environmental and energy impacts differ significantly.
According to the study, the gasification pathway was substantially more resource-efficient, cutting production costs by up to 46% while reducing electricity demand by as much as 30% compared with combustion-based alternatives.
Researchers say the findings reveal how energy-intensive some supposedly “green” fuel pathways can become when carbon dioxide must first be captured and then chemically rebuilt into fuel using large volumes of renewable electricity and hydrogen.
Johanna Beiron
“The difference shows how large the energy losses can be when biomass is first combusted into carbon dioxide, which is then rebuilt into fuel molecules using large amounts of electricity and hydrogen,” said Johanna Beiron, lead author of the study and researcher in Physical Resource Theory at Chalmers.
A major concern highlighted by the study is the growing demand for biomass.
The EU’s RFNBO framework was partly designed to reduce dependence on biomass and stimulate renewable electricity generation. Yet researchers argue the regulations may achieve the opposite outcome.
Because sustainable carbon sources are still needed to produce synthetic aviation fuels, the industry is expected to rely heavily on carbon dioxide captured from biomass combustion processes.
Researchers warn this could intensify competition for already limited biomass resources while encouraging less efficient uses of forestry and agricultural residues.
Under current EU rules, fuels produced through gasification are disadvantaged because RFNBO classifications restrict the use of carbon and energy directly sourced from biomass. Meanwhile, combustion-based pathways can still qualify under certain conditions if the carbon dioxide is captured after biomass is burned for energy generation.
The researchers argue that this creates a policy contradiction in which more energy-intensive systems receive stronger regulatory support than lower-emission, more efficient alternatives.
The study highlights what researchers describe as a structural problem in EU energy policy: climate regulations that focus narrowly on fuel classifications without fully accounting for total energy efficiency or resource consumption.
“The regulatory framework does not account sufficiently for how efficiently different systems use energy and resources,” said Thunman.
“Regulation risks working against its own objectives when definitions of sustainable fuels are not aligned with fundamental energy principles or with the Union’s broader ambitions for resource efficiency.”
The researchers say Europe’s transition to low-carbon aviation will require thousands of new fuel production facilities over the coming decades, involving major long-term investments. Without clearer alignment between climate policy, industrial strategy and environmental efficiency, there is a risk that the aviation sector could become locked into unnecessarily costly and energy-intensive technologies.
The Chalmers team is urging policymakers to reassess parts of the EU regulatory framework to ensure the clean energy transition delivers genuine environmental benefits rather than simply shifting emissions and energy burdens elsewhere in the system.
Researchers say technologies such as biomass gasification and electrified district heating could provide more sustainable long-term pathways while reducing pressure on electricity systems and biomass supply chains.
“The current regulatory framework risks causing lock-in to combustion-based energy systems, even though technically mature processes already exist that would provide both lower energy use and lower cost,” said Beiron.
The study concludes that future sustainable aviation fuel policies must balance carbon reduction targets with practical resource efficiency if Europe is to achieve a truly sustainable aviation sector.
Simon Harvey
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