A new study from Bosch advocates the use of synthetic fuels as a means of making internal combustion engines carbon neutral and extending their lifespan well into a more environmentally friendly future.

According to Bosch, the optimal type of synthetic fuel would be made with hydrogen extracted from water, and carbon captured the air or recycled from industrial sources. Through this process fuels, such as petrol, diesel, natural gas and kerosene, can be made.

The fuel can be synthesised in a carbon neutral manner if it's made in factories powered by renewable energy. Unlike biofuels, synthetic fuel production doesn't take up land and resources that could otherwise be used for food crops.

Additionally synthetic fuels could engineered to burn soot free, reducing the need for in-car exhaust treatment equipment. As synthetic fuels would have the same basic chemical properties as extracted and refined fuels, today's infrastructure could be used as is and existing vehicles would need no modification.

The study estimates a hybrid vehicle with a working life of 160,000km could cost the same to run as an electric vehicle, depending on the type of renewable energy used.

Bosch's study acknowledges currently "producing synthetic fuels is a complex and expensive process" with "considerable efforts ... still needed before synthetic fuels can become established".

At present there are only a few test plants functioning throughout the world, with pilot trials underway in Germany and Norway. Bosch predicts with increased production, refined manufacturing technology, and improved renewable energy pricing, the cost of synthetic petrol could eventually drop to between 1.00 and 1.40 euros ($1.49 and $2.08) per litre before excises and taxes are added.

The company believes even if all new passenger cars are successfully transitioned to electric drivetrains, there will still be a sizeable need for synthetic fuels, with planes, diesel trains, boats and classic cars still likely to use internal combustion engines.

No timeline is given for when synthetic fuels might be readily available, nor does the study outline the incentives or research investment required to accelerate their adoption.