Utilizing the Fischer-Tropsch process, an underutilized technique which has been around since the 1920's, Audi engineers were able to produce a clean-burning diesel fuel. Not only is the fuel carbon neutral, it can be poured directly into current cars of today without modifying the machinery.

The German car manufacturer announced in 2015 that it had successfully created an "e-diesel," or diesel containing ethanol, by using renewable energy to produce a liquid fuel using nothing more than water and carbon dioxide. With fuel prices on the rise once again, the news has gone viral for understandable reasons.

It took just four months for a plant in Dresden operated by clean tech company Sunfire to produce results using the Fischer-Tropsch process. The fuel, named "blue crude," is composed of long-chain hydrocarbon compounds. While it is similar to fossil fuels, it is free from sulfur and aromatics, therefore, burns soot-free.

The engineers' success can be attributed to the high temperatures used. The first step to create this eco-friendly diesel fuel is to harness renewable energy through solar, wind and/or hydropower. Then, engineers heat water to temperatures in excess of 800oC (1472oF). The steam gets broken down into oxygen and hydrogen through high-temperature electrolysis – a process where an electric current is passed through a solution, reports IFLScience. Once hydrogen is removed, it is mixed with carbon monoxide under high heat and pressure. This results in the formation of the hydrocarbon product they're calling "blue crude."

Credit: fostertire.blogspot.com