Audi creates 'e-diesel' from air and water

Audi TT

While car manufacturers are busy sinking billions into research and development to make their cars cleaner and more frugal and keep the wheels turning once the oil runs out, Audi is approaching the problem of dwindling fuel reserves from a different angle - by producing its own range of 'e-fuels'.

Last year the German carmaker perfected a new process for synthesising methane – a widely used automotive fuel source for natural gas vehicles – to create what has been dubbed 'e-gas'. The process involves extracting hydrogen from water using electrolysis and then combining it with carbon dioxide given off by natural waste.

Now, the manufacturer is concentrating its efforts on a fuel more likely to have a greater impact on private passenger vehicles: e-diesel.

Created from the same sustainable raw materials: air, water and electricity, Audi claims the new fuel is CO2 neutral. It is synthesised in a similar manner to natural gas, using a method called air capturing – developed by Swiss company Climeworks – which allows carbon dioxide to be captured from the atmosphere.

Once the CO2 has been harvested, an electrolysis machine is used to separate hydrogen and oxygen molecules from ordinary water. The hydrogen is then introduced to the CO2 in a heated, pressurised environment, resulting in the creation of a liquid known as Blue Crude.

This Blue Crude can then be converted to synthetic diesel, and can be mixed with regular diesel in any quantity. Synthetic diesel is free from many of the pollutants found in the traditionally manufactured fuel, including sulphur, and has a high cetane content, making it very combustible.

Audi is currently producing around 160 litres of e-diesel each day at its plant in Dresden as it perfects the process. It claims the techniques used are currently 70 per cent efficient.