E-diesel is the name of synthetic diesel created by Audi to be used in automobiles. Currently, an e-diesel variant is created by Audi research facility in partnership with a company named Sunfire. The fuel is created from carbon dioxide, a crude oil in a crude oil (which is then refined to generate e-diesel). E-diesel is considered to be a carbon-neutral fuel as it does not extract new carbon and energy sources from carbon-neutral sources. As of April 2015, an Audi A8 driven by the Federal Ministry of Education and Research in Germany is using e-diesel fuel.

Sunfire, a clean technology company, operates a pilot plant in Dresden, Germany. The current process involves high-temperature electrolysis powered by renewable energy sources. The next two chemical processes to a liquid energy carrier called blue crude are at a temperature of 220 C and a pressure of 25 bar. In a conversion step, hydrogen and carbon dioxide are used to create syngas with water as byproduct. The syngas, which contains carbon monoxide and hydrogen, reacts to generate blue crude. Climeworks which manufactures carbon dioxide capturing machines. Climeworks technologies can absorb atmospheric carbon dioxide which is chemically captured at the surface of a saturated saturated sorbent. At that point, the sorbent is introduced with 95 ° C in a desorption cycle to drive out the high-purity carbon dioxide that can be used during the conversion step of the blue crude generation process. The atmospheric carbon dioxide capturing process has 90% of energy demand in the form of low-temperature heat and the rest of electrical energy for pumping and control. The combined plant of Climeworks and Sunfire in Dresden has become operational in November 2014. A plant on Herøya in Norway, producing 10 million liters per year, is being considered, as it is a fertilizer. The atmospheric carbon dioxide capturing process has 90% of energy demand in the form of low-temperature heat and the rest of electrical energy for pumping and control. The combined plant of Climeworks and Sunfire in Dresden has become operational in November 2014. A plant on Herøya in Norway, producing 10 million liters per year, is being considered, as it is a fertilizer. The atmospheric carbon dioxide capturing process has 90% of energy demand in the form of low-temperature heat and the rest of electrical energy for pumping and control. The combined plant of Climeworks and Sunfire in Dresden has become operational in November 2014. A plant on Herøya in Norway, producing 10 million liters per year, is being considered, as it is a fertilizer.

As much as eighty percent of blue crude can be converted into e-diesel. The fuel contains no sulfur or aromatics, and has a high cetane number. These properties allow it to be blended with typical fossil diesel and used as a replacement fuel in automobiles with diesel engines.

In future designs, the oxygen by-product may be combined with renewable natural gas in the oxidative coupling of methane to ethylene :: 2 + & rd; + 2 The reaction is exothermic (ΔH = -280 kJ / mol) and occurs at high temperatures (750-950 ˚C). The yield of the product is reduced by non-selective reactions of methyl radicals with the reactor surface and oxygen, which produces carbon monoxide and carbon dioxide by-products. Another ethylene production initiative developed by the European Commission through the Seventh Framework Program for Research and Technological Development is the OCMOL process, which is the Oxidative Coupling of Methane (CMO) and Simultaneous Reforming of Methane (RM) in a fully integrated reactor.

Audi also partners with the United States company, Joule, to develop Joule’s Sunflow-D as e-diesel for Audi. Joule’s plant in New Mexico involves the use of microorganisms in the sun as a catalyst for the conversion of carbon dioxide and salty water into hydrocarbons. The process can be modified for long-term production of synthetic diesel. Joule Unlimited is the first company to patent a modified organism that continuously secretes hydrocarbon fuel. The organism is a single-celled cyanobacterium, also known as blue-green algae, although it is technically not an algae. It produces the fuel using photosynthesis, the same process that multi-cellular green plants use, to make sugars and other materials from water, carbon dioxide, and sunlight.

There are other initiatives to create synthetic fuel from carbon dioxide and water, however they are not part of Audi’s initiatives and the fuels are not called e-diesel. The water splitting methods vary.