Denmark has become the first European country to operate a domestic flight route powered with a significant blend of sustainable aviation fuel (SAF). Starting Wednesday at 3:25 PM, Norwegian Airlines will begin regular service between Aalborg and Copenhagen with 40 percent renewable fuel mixed into its tanks—a milestone that marks a significant step forward in greening the aviation industry.
The initiative stems from the Danish government’s “Green Aviation in Denmark” plan, which aims to reduce the environmental impact of domestic air travel. By blending renewable fuel with conventional jet fuel on this route, Danish aviation will eliminate approximately 3,000 tons of CO2 emissions annually.
Making sustainability more affordable
What sets this operation apart is that ticket prices remain unchanged despite the substantially higher cost of sustainable fuel. The secret lies in government subsidies that absorb the additional expense. Sustainable aviation fuel costs between seven and eight times more than traditional fossil fuel, yet passengers on the Aalborg-Copenhagen route will pay the same fares they always have.
“We are reducing CO2 emissions by 3,000 tons per year, so this is a step in the right direction,” says Sara Neergaard, country manager for Norwegian in Denmark.
However, Neergaard is careful not to label the operation as “green.” “As long as we still have fossil fuel in the tank, it is technically not green,” she explains. “It is certainly more sustainable than before, but since it’s not yet possible to fly on 100 percent SAF, we as a commercial airline cannot market it as green.”
Funding and infrastructure
The Danish government has allocated 800 million kroner (approximately €107 million) through 2029 to support sustainable domestic aviation through a levy on airline tickets. This substantial commitment reflects the government’s determination to transform the aviation sector.
Currently, only Aalborg Airport is equipped to fuel aircraft with the 40 percent sustainable fuel blend, which means the Copenhagen-to-Aalborg leg of the route will use the renewable fuel, while the return flight will operate on conventional fuel until Aalborg’s facilities are utilized.
The sustainable fuel itself comes from recycled cooking oil collected in European cities and processed in Gothenburg, Sweden, before being transported by ship to Aalborg Airport.
Questions about long-term strategy
Environmental organizations have raised thoughtful questions about Denmark’s approach. The Council for Green Business Reform suggests that while reducing emissions is crucial, the investment might yield better results if directed toward developing next-generation sustainable fuels.
“We support all measures that can reduce CO2 emissions from aviation,” notes Alexander Bjørn Hansen, transport advisor at the Council for Green Business Reform. “However, the current fuel comes primarily from used cooking oil, which is available in limited quantities. We need to develop other types of fuels as well.”
The aviation industry is exploring promising alternatives, including synthetic fuels (eFuels) produced using renewable electricity and hydrogen. Many environmental advocates argue that Denmark should prioritize research and development of these emerging technologies.
Looking ahead to 2030
International aviation regulations currently permit a maximum 50 percent sustainable fuel blend for safety reasons. Denmark’s ambition, however, extends well beyond the current 40 percent threshold.
The Danish government has set an ambitious target: all domestic flights within Denmark should operate on 100 percent sustainable fuel by 2030, if technically feasible at that time. This goal builds on an idea originally proposed by Prime Minister Mette Frederiksen in her 2022 New Year’s speech and was formalized through a government agreement on green aviation reached in December 2023.
According to Mathias Milling, director of the Danish Aviation Association within the Danish Industry Confederation, the new route will inspire change far beyond Denmark’s borders. “This will resonate around the world,” he says, “and now is the right moment to look forward to the next ambition set for 2030.”
