SWISS airline to use synthetic fuels made with solar energy

Switzerland’s national airline SWISS will use sustainable fuel manufactured with solar energy for its regular flight operations at Hamburg Airport, Germany.

Swiss-based clean tech company Synhelion has delivered a 190-litre barrel of synthetic crude oil from its DAWN production facility, which launched last year, to a refinery in Northern Germany. The oil, made using solar energy, was processed into Jet-A-1 aviation fuel.

The fuel was then fed into SWISS’s flight operations infrastructure via the fuel supply system at the airport.

“This is the first time that solar fuel has been used in civil aviation,” said SWISS CEO Jens Fehlinger.

Synhelion produces the fuel at its DAWN facility in Jülich, which features a 20m-high solar tower and mirror field, which contains a receiver, a thermochemical reactor, and thermal energy storage. 

Solar radiation is reflected by the mirror field, concentrated onto the receiver, and converted into high-temperature process heat. The generated heat is fed to the thermochemical reactor that produces syngas, a mixture of hydrogen and carbon monoxide.

Syngas is then processed by standard gas-to-liquids technology into fuels, such as jet fuel, gasoline, or diesel. The process can be made continuous by using excess heat saved in the thermal energy storage.

“Sustainable fuels are a key lever in reducing air transport’s reliance on fossil fuels,” said Philipp Furler, co-founder and co-CEO of Synhelion. 

Synhelion’s DAWN facility ©Synhelion

The fuel supplied makes up just 7% of the fuel required for a Hamburg to Zurich flight, but Furler sees it as a “symbolic action” towards a more sustainable aviation sector.

“This milestone brings us one step closer to globally scaling up our solar fuel technology,” he added. The company aims to do this by developing more facilities to ensure continuous production of the fuel, which will permit a commercial market entry from 2027.

Solar fuels like those developed by Synhelion fall under the category of synthetic sustainable aviation fuels (SAF), which use renewable energy and captured carbon to produce liquid hydrocarbons. 

Unlike bio-based SAF, they do not rely on biomass and have the potential to scale without affecting land use. To qualify under the EU Renewable Energy Directive, synthetic fuels must reduce lifecycle greenhouse gas emissions by at least 70% compared to fossil kerosene. 

An independent life cycle assessment of Synhelion’s process indicates it can exceed this threshold. The company is now working with SWISS to progress the certification of its production process in line with EU requirements.

While SAF remains a small share of the global aviation fuel mix, its role is expected to grow. The EU’s RefuelEU Aviation regulation will require at least 2% of aviation fuel to be SAF by 2025, rising to 6% by 2030 and 70% by 2050. 

A dedicated sub-target for synthetic fuels will also come into effect in 2030. Most SAF currently in use is derived from waste oils or other bio-based feedstocks. Synthetic fuels are still at an early stage but are expected to play an increasing role in decarbonising long-haul aviation where alternatives such as electrification are limited.