What if, instead of switching to batteries or fuel cells to reduce emissions, you could keep internal-combustion engines and simply put a different fuel in the tank? That's what McLaren COO Jens Ludmann is advocating for—or at least suggesting—as an alternative to electric cars.

McLaren plans to build a test car that will run on synthetic fuel, Ludmann said in an interview with Autocar, adding that the project is still in its early stages.

Ludmann said synthetic fuel could be a more practical way to reduce emissions. It could take advantage of the current infrastructure for gasoline and diesel, and current internal-combustion engines could burn it with only "small modifications," he said.

He didn't offer any details on the specific chemistry or process McLaren was considering, but said synthetic fuel could be produced using solar energy.

Ludmann noted that he doesn't expect synthetic fuel to replace batteries. "It's too hard to say with certainty how far off synthetic fuel is from reaching production reality," he said, "whereas battery technology is here."

McLaren 620R

McLaren 620R

Indeed, improvements in battery energy density and decreases in cost mean synthetic fuel's moment may have passed.

Audi previously produced small quantities of synthetic diesel, while some startups are still working on the technology.

Ludmann also said a synthetic-fuel engine could be used in future hybrid powertrains. His interest in keeping internal combustion going in some form matches that of McLaren CEO Mike Flewitt.

Flewitt recently criticized a United Kingdom government plan to end sales of new hybrid cars in 2032, saying hybrids will need to remain in the mix longer before an industry-wide shift to electric cars.

McLaren hasn't discussed concrete plans to launch an electric car, but it is reportedly planning a new plug-in hybrid model with more electric range than the previous P1.