The world drastically needs to reduce the amount of carbon dioxide released into the atmosphere – and fast. But until the mass adoption of carbon-neutral mobility becomes a reality, lower-carbon fuels must be found that can be used in conventional combustion engines across the board.

This was the driving logic behind the Karlsruhe Institute of Technology’s “reFuels – Rethinking Fuels” project, which last month completed a study to show that plant-based and electrolysis-synthesised fuels are suitable for use now in a wide variety of drives and can reduce carbon emissions by at least 25 percent, as well as showing an improvement in other air pollutants.

“In our mobility mix, liquid fuels will be needed for quite some time yet in long-distance heavy load traffic, shipping, aviation, and in existing private cars. Here, synthetic fuels can be a complementary solution for the defossilisation of transport,” says Dr Uwe Wagner from KIT’s Institut für Kolbenmaschinen (IFKM) in a press release. “For this purpose, they have to be produced sustainably and must be rapidly available.”

For the road tests conducted by KIT, a mixture of refuels was used in a variety of drives including commercially-available hydrotreated vegetable oil (HVO), as well as two new fuels developed in KIT’s labs. The bioliq® plant made synthetic gasoline from straw, while the Energy Lab 2.0 produced an e-fuel by electrolysis using regenerative power and CO2 from the air.

The driving trials took place in the city, the motorways, on country roads and on rail. Tests were also carried out on a fleet of trucks using CARE diesel (HVO) over a distance of 350,000 miles and on a rail engine using HVO plus R33. The fuels met the required performance standards such as EN590 for diesel and EN228 for gasoline.

Six KIT institutes are working on the project together with partners from the oil and auto industries within the state initiative Strategy Dialogue for the Automotive Sector in Baden-Württemberg.