Synthetic fuels

Renewable synthetic fuels: potential to reduce CO2 in existing powertrains

Anyone who takes environmental protection seriously cannot only hold new vehicles up as the answer – they need to offer solutions for existing vehicles, too. Internal-combustion engines powered by carbon-neutral, synthetic fuels are an important element of more eco-friendly mobility for this exact reason.

Renewable synthetic fuels: an interview with Ansgar Christ

Curbing CO2 emissions is one of the biggest challenges of our times. This goal can only be achieved if we considerably reduce the use of fossil fuels in the near future. This is where renewable synthetic fuels play a key role. Synthetic fuels generated from renewable energy sources ensure carbon-neutral combustion. This is not only true for new vehicles, but also for the 1.3 billion or so vehicles that already exist.

Ansgar Christ explains in an interview why transparency about CO2 is especially important, how future climate targets can be achieved with renewable synthetic fuels, and how sustainable fuel sources will be crucial for mobility in 2030.

Facts and figures on renewable synthetic fuels

In the future,


of all internal-combustion engines might be run on carbon-neutral fuels

1.3 billion

existing vehicles can be filled up with renewable fuels, thereby helping to achieve environmental targets

By 2050,

large-scale use of synthetic fuels could save gigatons in CO2 emissions.

Drop-in renewable fuels: filling up existing vehicles for carbon-neutral driving


Synthetic fuels offer great potential when it comes to achieving emissions targets. Here, the spotlight is on so-called drop-in renewable fuels. This term means that the respective fuel mixture conforms to standards like EN228 (gasoline), EN590 (diesel), or comparable alternatives.

Today, diesel vehicles can already be filled up with R33 fuel available at the pump, helping to reduce CO2 emissions by up to 20%. In principle, the CO2 saved can be anything up to 100% depending on the mixture and production method.

“Bosch and other companies are already using reduced-CO2 fuels in their corporate fleets. So, as you can see, the technical issues have been solved.”

Ansgar Christ

Ansgar Christ

Expert for synthetic and regenerative fuels at Bosch

Renewable synthetic fuels: advantages and challenges

Synthetic fuels

Drop-in-capable renewable synthetic fuels offer many advantages: they can either be admixed or used as a product in their own right. Older internal-combustion engines do not need to be modified to accept them, while existing gas stations can easily add renewable synthetic fuels to their range because the existing infrastructure can be used. CO2 can be drawn from the atmosphere for the production of renewable synthetic fuels, which establishes a carbon-neutral cycle and a practically limitless fuel supply.

The challenges of renewable synthetic fuels: for carbon-neutral production, they require electricity generated from renewable sources, the supply of which is still insufficient. Current production facilities for renewable synthetic fuels have low capacity and high production costs. Yet by expanding production capacity and benefiting from the lower costs associated with this, renewable synthetic fuels could soon become much more affordable.

Biofuels: advantages and challenges


Bosch promotes the use of biofuels produced from residual and waste materials. Their potential to minimize CO2 emissions makes biofuels an important factor for environmental protection and for satisfying legislation on the reduction of greenhouse gases. Biofuels must satisfy the EU’s sustainability criteria.

The poor availability of drop-in-capable components is one current challenge that must be overcome if biofuels are to be rolled out on a wide scale.

C.A.R.E. diesel

C.A.R.E. diesel is fuel produced from residual and waste materials. This paraffinic fuel, which is up to 100% renewable, is produced from biological waste (such as used cooking oil and grease) and contains zero conventional diesel from fossil sources.

C.A.R.E. is a trademark registered by Toolfuel and stands for the fuel’s four advantages: CO2 reduction, Arctic grade (cold resistance), Renewable, and Emission reduction.

R33 Blue Diesel

Up to 33% of R33 Blue Diesel fuel consists of biological components, with the remaining 67% comprising diesel. Using this fuel guarantees a 20% reduction in CO2. Furthermore, the fuel is compliant with fuel standard EN 590, enabling it to be sold from public gas stations.

The biological share of this fuel is exclusively produced from waste material and by-products like used cooking oil.

Gasoline + ethanol (E-xx)

Ethanol is a type of alcohol extracted from plants that is also is used as a fuel. Until now, ethanol has mainly been produced from sugar cane or starchy plants. Yet new technologies are based on using biomass from raw materials containing cellulose, such as maiden silvergrass.

In this way, ethanol notably reduces the carbon footprint and is admixed to conventional gasoline. The ethanol content varies between 5% (E5) and 85% (E85) in this case.

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