Carbon-neutral synthetic fuels have the potential to keep the internal-combustion engine toiling away for decades to come, though Mercedes-Benz doesn't see this actually happening.

In an interview with Autocar published Thursday, Markus Schaefer, head of R&D at the German automaker, said synthetic fuels aren't viable in cars, even in the mid-term, and that electricity is a much better solution.

“If you have an abundance of energy, the best use is to put it directly into a battery,” he said. “To transform green energy into an e-fuel is a process where you lose a lot of efficiency.”

He added that sythetic fuels, if available in commercial volumes, would likely be used first in the aviation industry rather than the car industry.

For these reasons, Mercedes is thinking electric cars first but is ready with other solutions in case of alternative regulations and consumer tastes.

There are multiple methods for creating synthetic fuels, though they're all energy intensive. The most common type of synthetic fuel is oxymethylene ether (OME), which can be generated for gasoline and diesel cars.

OME can be produced using CO2 from the air, in a process that combines the CO2 with hydrogen generated by electrolysis of water. The electricity required for the electrolysis process can be generated via renewable energy sources like wind or solar farms.

The challenge is generating the hydrogen in a manner that makes OME commercially viable. When that might happen, if at all, is hard to say, although many in the industry, including Porsche CEO Oliver Blume, see it as a possibility in about ten years.