Audi Is Making Diesel Fuel From Water And Carbon Dioxide

Not a new technology (South Africa is still producing liquid fuels from coal using F-T) but definitely interesting in the use of CO2 as the carbon feedstock.
From IFL Science:

It’s the holy grail in energy production: produce a fuel that is both carbon neutral and can be poured directly into our current cars without the need to retrofit. There are scores of companies out there trying to do just that using vegetable oil, algae, and even the microbes found in panda poop to turn bamboo into fuel.

This week, German car manufacturer Audi has declared that they have been able to create an "e-diesel," or diesel containing ethanol, by using renewable energy to produce a liquid fuel from nothing more than water and carbon dioxide. After a commissioning phase of just four months, the plant in Dresden operated by clean tech company Sunfire has managed to produce its first batch of what they’re calling “blue crude.” The product liquid is composed of long-chain hydrocarbon compounds, similar to fossil fuels, but free from sulfur and aromatics and therefore burns soot-free.

The first step in the process involves harnessing renewable energy through solar, wind or hydropower. This energy is then used to heat water to temperatures in excess of 800^oC (1472^oF). The steam is then broken down into oxygen and hydrogen through high temperature electrolysis, a process where an electric current is passed through a solution.

The hydrogen is then removed and mixed with carbon monoxide under high heat and pressure, creating a hydrocarbon product they’re calling "blue crude." Sunfire claim that the synthetic fuel is not only more environmentally friendly than fossil fuel, but that the efficiency of the overall process—from renewable power to liquid hydrocarbon—is very high at around 70%. The e-diesel can then be either mixed with regular diesel, or used as a fuel in its own right.

But all may not be as it seems. The process used by Audi is actually called the Fischer-Tropsch process and has been known by scientists since the 1920s. It was even used by the Germans to turn coal into diesel during the Second World War when fuel supplies ran short. The process is currently used by many different companies all around the world, especially in countries where reserves of oil are low but reserves of other fossils fuels, such as gas and coal, are high....MORE